diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/CMakeLists.txt | 95 | ||||
| -rw-r--r-- | doc/ChangeLog | 112 | ||||
| -rw-r--r-- | doc/Makefile.am | 14 | ||||
| -rw-r--r-- | doc/Makefile.in | 30 | ||||
| -rw-r--r-- | doc/awkcard.in | 3 | ||||
| -rw-r--r-- | doc/gawk.1 | 72 | ||||
| -rw-r--r-- | doc/gawk.info | 1859 | ||||
| -rw-r--r-- | doc/gawk.texi | 551 | ||||
| -rw-r--r-- | doc/gawktexi.in | 551 |
9 files changed, 2445 insertions, 842 deletions
diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt new file mode 100644 index 00000000..e12f5de0 --- /dev/null +++ b/doc/CMakeLists.txt @@ -0,0 +1,95 @@ +# +# doc/CMakeLists.txt --- CMake input file for gawk +# +# Copyright (C) 2013 +# the Free Software Foundation, Inc. +# +# This file is part of GAWK, the GNU implementation of the +# AWK Programming Language. +# +# GAWK is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# GAWK is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA +# + +## process this file with CMake to produce Makefile + +MACRO(DocDependency outfile) + add_dependencies(doc ${outfile}) + add_custom_target( + ${outfile} + DEPENDS ${ARGN} + WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} + COMMAND ${CMAKE_SOURCE_DIR}/cmake/docmaker ${outfile} ${ARGN} + ) +ENDMACRO(DocDependency) + +find_program(TEXI2DVI_CONVERTER texi2dvi) +if (TEXI2DVI_CONVERTER) + add_custom_target(doc) + DocDependency(gawk.texi gawktexi.in rflashlight.eps api-figure1.fig api-figure2.fig api-figure3.fig general-program.fig process-flow.fig) + DocDependency(rflashlight.eps) + DocDependency(api-figure1.fig) + DocDependency(api-figure2.fig) + DocDependency(api-figure3.fig) + DocDependency(general-program.fig) + DocDependency(process-flow.fig) + DocDependency(gawk.dvi gawk.texi) + DocDependency(gawk.info gawk.texi) + DocDependency(gawkinet.dvi gawkinet.texi) + DocDependency(gawkinet.info gawkinet.texi) + DocDependency(gawkinet.texi statist.eps) + DocDependency(gawk.1.ps gawk.1) + DocDependency(igawk.1.ps igawk.1) + find_program(DVIPS_CONVERTER dvips) + if (DVIPS_CONVERTER) + DocDependency(gawk.ps gawk.dvi) + DocDependency(gawkinet.ps gawkinet.dvi) + find_program(PS2PDF_CONVERTER ps2pdf) + if (PS2PDF_CONVERTER) + DocDependency(gawk.1.pdf gawk.1.ps) + DocDependency(igawk.1.pdf igawk.1.ps) + DocDependency(gawk.pdf gawk.ps) + DocDependency(gawkinet.pdf gawkinet.ps) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/gawk.1.pdf DESTINATION doc) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/igawk.1.pdf DESTINATION doc) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/gawk.info DESTINATION doc) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/gawk.pdf DESTINATION doc) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/gawkinet.info DESTINATION doc) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/gawkinet.pdf DESTINATION doc) + + set(CARDSRC macros cardfonts colors awkcard.tr) + set(CARDSRC_N macros cardfonts no.colors awkcard.tr) + set(CARDFILES ${CARDSRC} ad.block awkcard.in setter.outline) + DocDependency(awkcard.tr awkcard.in) + DocDependency(awkcard.nc ${CARDFILES}) + DocDependency(awkcard.ps ${CARDFILES}) + DocDependency(awkcard.pdf awkcard.ps) + install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/awkcard.pdf DESTINATION doc) + + else() + message(WARNING "Found no ps2pdf tool; no doc will be generated") + install(CODE "MESSAGE(\"doc generated only in .ps files\")") + endif() + else() + message(WARNING "Found no dvips tool; no doc will be generated") + install(CODE "MESSAGE(\"doc generated only in .dvi files and man pages in .ps files\")") + endif() +else() + message(WARNING "Found no texi2dvi tool; no doc will be generated") + add_custom_command( + TARGET doc + COMMAND echo no doc generated because of missing texi2dvi + ) +endif() + diff --git a/doc/ChangeLog b/doc/ChangeLog index a5c546e3..f38b795a 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -2,6 +2,10 @@ * 4.1.2: Release tar ball made. +2015-04-16 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in (Undocumented): More info added. + 2015-04-08 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Update feature history section. @@ -23,6 +27,11 @@ * gawktexi.in: Fix a figure caption. Thanks to Antonio Colombo for pointing this out. + * gawktexi.in: Additional typo fix, also thanks to Antonio. + +2015-04-02 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in, gawk.1, awkcard.in: Name change: div() --> intdiv(). 2015-03-31 Arnold D. Robbins <arnold@skeeve.com> @@ -30,10 +39,17 @@ indirectly. Small additional fix relating to rand(). Thanks to Antonio Colombo. +2015-03-27 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Minor edits. + 2015-03-24 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Minor fixes from Antonio Colombo and new exercise in chapter 16. + * gawk.1: Minor edits. + * gawktexi.in: Edits in material on errno and retryable and get_file + API. 2015-03-17 Andrew J. Schorr <aschorr@telemetry-investments.com> @@ -47,6 +63,12 @@ Thanks to Nicholas Mills <nlmills@clemson.edu> for pointing out the issue. +2015-03-08 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Briefly describe that nonfatal I/O overrides + GAWK_SOCK_RETRIES, in the env var part and in the nonfatal I/O + part. + 2015-03-01 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Change quotes to @dfn for pseudorandom. @@ -103,6 +125,7 @@ 2015-02-08 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: O'Reilly fixes. + Make non-fatal i/o use "NONFATAL". 2015-02-06 Arnold D. Robbins <arnold@skeeve.com> @@ -111,6 +134,7 @@ 2015-02-04 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: O'Reilly fixes. + * gawktexi.in: Update various version-related bits of info. 2015-02-02 Arnold D. Robbins <arnold@skeeve.com> @@ -140,7 +164,7 @@ 2015-01-25 Arnold D. Robbins <arnold@skeeve.com> - * gawktexi.in: Fix a bad URL. + * gawktexi.in: Fix a bad URL. And another one. More O'Reilly fixes. 2015-01-23 Arnold D. Robbins <arnold@skeeve.com> @@ -162,12 +186,40 @@ * gawkinet.texi: Fix capitalization in document title. * gawktexi.in: Here we go again: Starting on more O'Reilly fixes. +2014-12-27 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Add info that nonfatal I/O works with stdout and + stderr. Revise version info and what was added when. + +2015-01-05 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawktexi.in: Improve get_file documentation. + +2015-01-05 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawktexi.in: Replace "Retrying I/O" with "Retrying Input", since this + feature pertains to input, not output. + +2015-01-04 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawktexi.in: Document the get_file API function. + +2015-01-04 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawk.1: Document new features PROCINFO["errno"] and + PROCINFO["input", "RETRY"], and new getline return value of -2. + * gawktexi.in: Ditto. + 2014-12-26 Antonio Giovanni Colombo <azc100@gmail.com> * gawktexi.in (Glossary): Really sort the items. 2014-12-24 Arnold D. Robbins <arnold@skeeve.com> + * gawktexi.in: Start documenting nonfatal output. + +2014-12-24 Arnold D. Robbins <arnold@skeeve.com> + * gawktexi.in: Add one more paragraph to new foreword. * gawktexi.in: Fix exponentiation in TeX mode. Thanks to Marco Curreli by way of Antonio Giovanni Colombo. @@ -199,6 +251,11 @@ * gawktexi.in: Various minor fixes and updates. +2014-11-23 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Update that TZ env. var can influnce mktime + in running program. Thanks to Hermann Peifer. + 2014-11-19 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Update that RFC 4180 documents CSV data. @@ -212,6 +269,11 @@ * gawktexi.in: Comment out that I need an owner for awk.info. I may have found one or two people. +2014-10-29 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawktexi.in: Document new extras directory containing shell startup + files to manipulate AWKPATH and AWKLIBPATH environment variables. + 2014-10-28 Arnold D. Robbins <arnold@skeeve.com> * gawk.1: Clarification that debugger reads stdin. @@ -225,6 +287,7 @@ 2014-10-25 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Minor typo fixes. + Fix discussion of \x, per note from Antonio Colombo. 2014-10-17 Arnold D. Robbins <arnold@skeeve.com> @@ -266,10 +329,25 @@ * gawktexi.in: Pretty much done! + Unrelated: + + * gawktexi.in: Fix braino in awk version of div function. + Thanks to Katie Wasserman for the catch. + 2014-10-01 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: More fixes after reading through the MS. + Unrelated: + + * gawktexi.in: Add Katie Wasserman's program to compute + the digits of PI. + + Unrelated: + + * gawktexi.in: Document the differences between profiling + and pretty printing. + 2014-09-30 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: More fixes after reading through the MS. @@ -365,6 +443,10 @@ exercises. Remove use of LC_ALL in an example; doesn't seem to be needed anymore. + Unrelated: + + * gawktexi.in: Document that MirBSD is no longer supported. + 2014-08-25 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Exercises are excluded from print edition. @@ -398,6 +480,10 @@ * gawktexi.in: Starting on reviewer comments. Update acknowledgements. +2014-08-12 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Cause div.awk to get into the example files. + 2014-08-06 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Misc minor additions. @@ -412,6 +498,18 @@ * gawktexi.in: Fix doc for API get_record - errcode needs to be greater than zero. +2014-07-24 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in (Numeric Functions): For `div()', clarify + truncation is towards zero. Thanks to Michal Jaegermann + for pointing out the need to clarify this. + +2014-07-10 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in (Numeric Functions): Document new `div()' function. + (Arbitrary Precision Integers): Document raison d'etre for div(). + * gawk.1, awkcard.in: Document `div()'. + 2014-07-04 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in (Bracket Expressions): Add a note about how to @@ -422,6 +520,11 @@ * gawktexi.in: Update permissions on copyright page per latest maintain.texi. Add GPL to print version of book. +2014-06-24 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Document that --pretty-print no longer runs the + program. Remove mention of GAWK_NO_PP_RUN env var. + 2014-06-22 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Typo fixes and minor corrections. @@ -718,7 +821,7 @@ 2013-12-26 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: More minor additions / fixes. - (Bugs): Add John Malmberg for VMS. + (Bugs): Add John Malmberg for VMS. Other minor edits. 2013-12-25 Arnold D. Robbins <arnold@skeeve.com> @@ -792,6 +895,11 @@ * gawktexi.in (FN, FFN, DF,DDF, PVERSION, CTL): Remove macros. They have no alternate versions and are just in the way. +2013-08-15 Arnold D. Robbins <arnold@skeeve.com> + + * gawk.1: Document that ENVIRON updates affect the environment. + * gawktexi.in: Ditto. + 2013-06-27 Arnold D. Robbins <arnold@skeeve.com> * texinfo.tex: Update from Karl, fixes a formating problem. diff --git a/doc/Makefile.am b/doc/Makefile.am index 86321bbc..8a0442a7 100644 --- a/doc/Makefile.am +++ b/doc/Makefile.am @@ -26,7 +26,7 @@ info_TEXINFOS = gawk.texi gawkinet.texi -man_MANS = gawk.1 igawk.1 +man_MANS = gawk.1 EXTRA_DIST = ChangeLog ChangeLog.0 README.card ad.block setter.outline \ awkcard.in awkforai.txt texinfo.tex cardfonts \ @@ -50,7 +50,7 @@ EXTRA_DIST = ChangeLog ChangeLog.0 README.card ad.block setter.outline \ bc_notes # Get rid of generated files when cleaning -CLEANFILES = *.ps *.html *.dvi *~ awkcard.nc awkcard.tr gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf igawk.1.pdf +CLEANFILES = *.ps *.html *.dvi *~ awkcard.nc awkcard.tr gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf MAKEINFO = @MAKEINFO@ --no-split --force @@ -75,9 +75,9 @@ AWKCARD = awkcard.ps gawk.texi: $(srcdir)/gawktexi.in $(srcdir)/sidebar.awk awk -f $(srcdir)/sidebar.awk < $(srcdir)/gawktexi.in > gawk.texi -postscript: gawk.ps gawkinet.ps gawk.1.ps igawk.1.ps $(AWKCARD) +postscript: gawk.ps gawkinet.ps gawk.1.ps $(AWKCARD) -pdf: postscript gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf igawk.1.pdf +pdf: postscript gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf gawk.ps: gawk.dvi TEXINPUTS=$(srcdir): dvips -o gawk.ps gawk.dvi @@ -91,12 +91,6 @@ gawk.1.ps: gawk.1 gawk.1.pdf: gawk.1.ps ps2pdf gawk.1.ps gawk.1.pdf -igawk.1.ps: igawk.1 - -groff -man $(srcdir)/igawk.1 > igawk.1.ps - -igawk.1.pdf: igawk.1.ps - ps2pdf igawk.1.ps igawk.1.pdf - awkcard.tr: awkcard.in sed 's:SRCDIR:$(srcdir):' < $(srcdir)/awkcard.in > awkcard.tr diff --git a/doc/Makefile.in b/doc/Makefile.in index 30a371d7..0219bc97 100644 --- a/doc/Makefile.in +++ b/doc/Makefile.in @@ -116,14 +116,14 @@ ACLOCAL_M4 = $(top_srcdir)/aclocal.m4 am__aclocal_m4_deps = $(top_srcdir)/m4/arch.m4 \ $(top_srcdir)/m4/codeset.m4 $(top_srcdir)/m4/gettext.m4 \ $(top_srcdir)/m4/iconv.m4 $(top_srcdir)/m4/intlmacosx.m4 \ - $(top_srcdir)/m4/isc-posix.m4 $(top_srcdir)/m4/lcmessage.m4 \ - $(top_srcdir)/m4/lib-ld.m4 $(top_srcdir)/m4/lib-link.m4 \ - $(top_srcdir)/m4/lib-prefix.m4 $(top_srcdir)/m4/libsigsegv.m4 \ - $(top_srcdir)/m4/longlong.m4 $(top_srcdir)/m4/mpfr.m4 \ - $(top_srcdir)/m4/nls.m4 $(top_srcdir)/m4/noreturn.m4 \ - $(top_srcdir)/m4/po.m4 $(top_srcdir)/m4/progtest.m4 \ - $(top_srcdir)/m4/readline.m4 $(top_srcdir)/m4/socket.m4 \ - $(top_srcdir)/m4/ulonglong.m4 $(top_srcdir)/configure.ac + $(top_srcdir)/m4/lcmessage.m4 $(top_srcdir)/m4/lib-ld.m4 \ + $(top_srcdir)/m4/lib-link.m4 $(top_srcdir)/m4/lib-prefix.m4 \ + $(top_srcdir)/m4/libsigsegv.m4 $(top_srcdir)/m4/longlong.m4 \ + $(top_srcdir)/m4/mpfr.m4 $(top_srcdir)/m4/nls.m4 \ + $(top_srcdir)/m4/noreturn.m4 $(top_srcdir)/m4/po.m4 \ + $(top_srcdir)/m4/progtest.m4 $(top_srcdir)/m4/readline.m4 \ + $(top_srcdir)/m4/socket.m4 $(top_srcdir)/m4/ulonglong.m4 \ + $(top_srcdir)/configure.ac am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \ $(ACLOCAL_M4) DIST_COMMON = $(srcdir)/Makefile.am $(am__DIST_COMMON) @@ -353,7 +353,7 @@ top_build_prefix = @top_build_prefix@ top_builddir = @top_builddir@ top_srcdir = @top_srcdir@ info_TEXINFOS = gawk.texi gawkinet.texi -man_MANS = gawk.1 igawk.1 +man_MANS = gawk.1 EXTRA_DIST = ChangeLog ChangeLog.0 README.card ad.block setter.outline \ awkcard.in awkforai.txt texinfo.tex cardfonts \ api-figure1.eps api-figure1.fig api-figure1.pdf \ @@ -377,7 +377,7 @@ EXTRA_DIST = ChangeLog ChangeLog.0 README.card ad.block setter.outline \ # Get rid of generated files when cleaning -CLEANFILES = *.ps *.html *.dvi *~ awkcard.nc awkcard.tr gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf igawk.1.pdf +CLEANFILES = *.ps *.html *.dvi *~ awkcard.nc awkcard.tr gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf TROFF = groff -t -Tps -U SEDME = sed -e "s/^level0 restore/level0 restore flashme 100 72 moveto (Copyright `date '+%m-%d-%y %T'`, FSF, Inc. (all)) show/" \ -e "s/^\/level0 save def/\/level0 save def 30 -48 translate/" @@ -878,9 +878,9 @@ uninstall-man: uninstall-man1 gawk.texi: $(srcdir)/gawktexi.in $(srcdir)/sidebar.awk awk -f $(srcdir)/sidebar.awk < $(srcdir)/gawktexi.in > gawk.texi -postscript: gawk.ps gawkinet.ps gawk.1.ps igawk.1.ps $(AWKCARD) +postscript: gawk.ps gawkinet.ps gawk.1.ps $(AWKCARD) -pdf: postscript gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf igawk.1.pdf +pdf: postscript gawk.pdf gawkinet.pdf awkcard.pdf gawk.1.pdf gawk.ps: gawk.dvi TEXINPUTS=$(srcdir): dvips -o gawk.ps gawk.dvi @@ -894,12 +894,6 @@ gawk.1.ps: gawk.1 gawk.1.pdf: gawk.1.ps ps2pdf gawk.1.ps gawk.1.pdf -igawk.1.ps: igawk.1 - -groff -man $(srcdir)/igawk.1 > igawk.1.ps - -igawk.1.pdf: igawk.1.ps - ps2pdf igawk.1.ps igawk.1.pdf - awkcard.tr: awkcard.in sed 's:SRCDIR:$(srcdir):' < $(srcdir)/awkcard.in > awkcard.tr diff --git a/doc/awkcard.in b/doc/awkcard.in index 310eb22d..6cfa1df1 100644 --- a/doc/awkcard.in +++ b/doc/awkcard.in @@ -1611,6 +1611,9 @@ l lw(2i). \*(FCcos(\*(FIexpr\*(FC)\*(FR The cosine of \*(FIexpr\fP, which is in radians. \*(FCexp(\*(FIexpr\*(FC)\*(FR The exponential function (\*(FIe \*(FC^ \*(FIx\*(FR). \*(FCint(\*(FIexpr\*(FC)\*(FR Truncate to integer. +\*(CB\*(FCintdiv(\*(FIn\*(FR\*(FC,\*(FI d\*(FR\*(FC,\*(FI res\*(FR\*(FC)\*(FR T{ +Return the result of integer division in \*(FIres\*(FR.\*(CD +T} \*(FClog(\*(FIexpr\*(FC)\*(FR The natural logarithm function (base \*(FIe\^\*(FR). \*(FCrand()\fP A random number \*(FIN\fP such that 0 \(<= \*(FIN\fP < 1. \*(FCsin(\*(FIexpr\*(FC)\*(FR The sine of \*(FIexpr\fP, which is in radians. @@ -13,7 +13,7 @@ . if \w'\(rq' .ds rq "\(rq . \} .\} -.TH GAWK 1 "Aug 03 2014" "Free Software Foundation" "Utility Commands" +.TH GAWK 1 "Apr 02 2015" "Free Software Foundation" "Utility Commands" .SH NAME gawk \- pattern scanning and processing language .SH SYNOPSIS @@ -918,11 +918,17 @@ An array containing the values of the current environment. The array is indexed by the environment variables, each element being the value of that variable (e.g., \fBENVIRON["HOME"]\fP might be \fB"/home/arnold"\fR). -Changing this array does not affect the environment seen by programs which +.sp +In POSIX mode, +changing this array does not affect the environment seen by programs which .I gawk spawns via redirection or the .B system() function. +Otherwise, +.I gawk +updates its real environment so that programs it spawns see +the changes. .TP .B ERRNO If a system error occurs either doing a redirection for @@ -936,6 +942,15 @@ then will contain a string describing the error. The value is subject to translation in non-English locales. +If the string in +.B ERRNO +corresponds to a system error in the +.IR errno (3) +variable, then the numeric value can be found in +.B PROCINFO["errno"]. +For non-system errors, +.B PROCINFO["errno"] +will be zero. .TP .B FIELDWIDTHS A whitespace separated list of field widths. When set, @@ -1097,6 +1112,13 @@ system call. The default time format string for .BR strftime() . .TP +\fBPROCINFO["errno"]\fP +The value of +.IR errno (3) +when +.BR ERRNO +is set to the associated error message. +.TP \fBPROCINFO["euid"]\fP The value of the .IR geteuid (2) @@ -1215,6 +1237,28 @@ where is a redirection string or a filename. A value of zero or less than zero means no timeout. .TP +\fBPROCINFO["input", "RETRY"]\fP +If an I/O error that may be retried occurs when reading data from +.IR input , +and this array entry exists, then +.B getline +will return \-2 instead of following the default behavior of returning \-1 +and configuring +.IR input +to return no further data. +An I/O error that may be retried is one where +.IR errno (3) +has the value +.IR EAGAIN , +.IR EWOULDBLOCK , +.IR EINTR , +or +.IR ETIMEDOUT . +This may be useful in conjunction with +\fBPROCINFO["input", "READ_TIMEOUT"]\fP +or situations where a file descriptor has been configured to behave in a +non-blocking fashion. +.TP \fBPROCINFO["mpfr_version"]\fP The version of the GNU MPFR library used for arbitrary precision number support in @@ -2283,6 +2327,13 @@ below.) The .B getline command returns 1 on success, 0 on end of file, and \-1 on an error. +If the +.IR errno (3) +value indicates that the I/O operation may be retried, +and \fBPROCINFO["input", "RETRY"]\fP +is set, then \-2 will be returned instead of \-1, and further calls to +.B getline +may be attempted. Upon an error, .B ERRNO is set to a string describing the problem. @@ -2635,6 +2686,23 @@ The exponential function. .BI int( expr ) Truncate to integer. .TP +.BI intdiv( num ", " denom ", " result ) +Truncate +.I num +and +.I denom +to integers. Return the quotient of +.I num +divided by +.I denom +in \fIresult\fB["quotient"]\fR +and the remainder in +in \fIresult\fB["remainder"]\fR. +This is a +.I gawk +extension, primarily of value when working with +arbitrarily large integers. +.TP .BI log( expr ) The natural logarithm function. .TP diff --git a/doc/gawk.info b/doc/gawk.info index eb9aec15..c7fd5c36 100644 --- a/doc/gawk.info +++ b/doc/gawk.info @@ -217,6 +217,7 @@ entitled "GNU Free Documentation License". `getline'. * Getline Summary:: Summary of `getline' Variants. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -246,6 +247,7 @@ entitled "GNU Free Documentation License". * Special Caveats:: Things to watch out for. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. * Values:: Constants, Variables, and Regular @@ -557,6 +559,7 @@ entitled "GNU Free Documentation License". * Array Functions:: Functions for working with arrays. * Flattening Arrays:: How to flatten arrays. * Creating Arrays:: How to create and populate arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension Versioning:: API Version information. * Extension API Informational Variables:: Variables providing information about @@ -615,6 +618,7 @@ entitled "GNU Free Documentation License". * Unix Installation:: Installing `gawk' under various versions of Unix. * Quick Installation:: Compiling `gawk' under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. * Non-Unix Installation:: Installation on Other Operating @@ -2640,10 +2644,8 @@ The following list describes options mandated by the POSIX standard: different file name for the output. No space is allowed between the `-o' and FILE, if FILE is supplied. - NOTE: Due to the way `gawk' has evolved, with this option - your program still executes. This will change in the next - major release, such that `gawk' will only pretty-print the - program and not run it. + NOTE: In the past, this option would also execute your + program. This is no longer the case. `-O' `--optimize' @@ -2943,6 +2945,9 @@ Since `.' is included at the beginning, `gawk' searches first in the current directory and then in `/usr/local/share/awk'. In practice, this means that you will rarely need to change the value of `AWKPATH'. + *Note Shell Startup Files::, for information on functions that help +to manipulate the `AWKPATH' variable. + `gawk' places the value of the search path that it used into `ENVIRON["AWKPATH"]'. This provides access to the actual search path value from within an `awk' program. @@ -2982,6 +2987,9 @@ empty value, `gawk' uses a default path; this is typically `/usr/local/lib/gawk', although it can vary depending upon how `gawk' was built. + *Note Shell Startup Files::, for information on functions that help +to manipulate the `AWKLIBPATH' variable. + `gawk' places the value of the search path that it used into `ENVIRON["AWKLIBPATH"]'. This provides access to the actual search path value from within an `awk' program. @@ -3008,7 +3016,8 @@ used by regular users: `GAWK_SOCK_RETRIES' Controls the number of times `gawk' attempts to retry a two-way TCP/IP (socket) connection before giving up. *Note TCP/IP - Networking::. + Networking::. Note that when nonfatal I/O is enabled (*note + Nonfatal::), `gawk' only tries to open a TCP/IP socket once. `POSIXLY_CORRECT' Causes `gawk' to switch to POSIX-compatibility mode, disabling all @@ -3053,13 +3062,6 @@ change. The variables are: supposed to be differences, but occasionally theory and practice don't coordinate with each other.) -`GAWK_NO_PP_RUN' - When `gawk' is invoked with the `--pretty-print' option, it will - not run the program if this environment variable exists. - - CAUTION: This variable will not survive into the next major - release. - `GAWK_STACKSIZE' This specifies the amount by which `gawk' should grow its internal evaluation stack, when needed. @@ -3451,15 +3453,18 @@ sequences apply to both string constants and regexp constants: `\xHH...' The hexadecimal value HH, where HH stands for a sequence of - hexadecimal digits (`0'-`9', and either `A'-`F' or `a'-`f'). Like - the same construct in ISO C, the escape sequence continues until - the first nonhexadecimal digit is seen. (c.e.) However, using - more than two hexadecimal digits produces undefined results. (The - `\x' escape sequence is not allowed in POSIX `awk'.) - - CAUTION: The next major release of `gawk' will change, such - that a maximum of two hexadecimal digits following the `\x' - will be used. + hexadecimal digits (`0'-`9', and either `A'-`F' or `a'-`f'). A + maximum of two digts are allowed after the `\x'. Any further + hexadecimal digits are treated as simple letters or numbers. + (c.e.) (The `\x' escape sequence is not allowed in POSIX awk.) + + CAUTION: In ISO C, the escape sequence continues until the + first nonhexadecimal digit is seen. For many years, `gawk' + would continue incorporating hexadecimal digits into the + value until a non-hexadecimal digit or the end of the string + was encountered. However, using more than two hexadecimal + digits produced undefined results. As of version 4.2, only + two digits are processed. `\/' A literal slash (necessary for regexp constants only). This @@ -4175,6 +4180,7 @@ have to be named on the `awk' command line (*note Getline::). * Getline:: Reading files under explicit program control using the `getline' function. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -5447,6 +5453,11 @@ record, such as a file that cannot be opened, then `getline' returns -1. In this case, `gawk' sets the variable `ERRNO' to a string describing the error that occurred. + If `ERRNO' indicates that the I/O operation may be retried, and +`PROCINFO["INPUT", "RETRY"]' is set, then `getline' returns -2 instead +of -1, and further calls to `getline' may be attemped. *Note Retrying +Input::, for further information about this feature. + In the following examples, COMMAND stands for a string value that represents a shell command. @@ -5883,7 +5894,7 @@ VAR Table 4.1: `getline' variants and what they set -File: gawk.info, Node: Read Timeout, Next: Command-line directories, Prev: Getline, Up: Reading Files +File: gawk.info, Node: Read Timeout, Next: Retrying Input, Prev: Getline, Up: Reading Files 4.10 Reading Input with a Timeout ================================= @@ -5962,7 +5973,8 @@ a per-command or per-connection basis. `gawk' considers a timeout event to be an error even though the attempt to read from the underlying device may succeed in a later attempt. This is a limitation, and it also means that you cannot use -this to multiplex input from two or more sources. +this to multiplex input from two or more sources. *Note Retrying +Input::, for a way to enable later I/O attempts to succeed. Assigning a timeout value prevents read operations from blocking indefinitely. But bear in mind that there are other ways `gawk' can @@ -5977,9 +5989,36 @@ writing. (1) This assumes that standard input is the keyboard. -File: gawk.info, Node: Command-line directories, Next: Input Summary, Prev: Read Timeout, Up: Reading Files +File: gawk.info, Node: Retrying Input, Next: Command-line directories, Prev: Read Timeout, Up: Reading Files + +4.11 Retrying Reads After Certain Input Errors +============================================== + +This minor node describes a feature that is specific to `gawk'. + + When `gawk' encounters an error while reading input, by default +`getline' returns -1, and subsequent attempts to read from that file +result in an end-of-file indication. However, you may optionally +instruct `gawk' to allow I/O to be retried when certain errors are +encountered by setting a special element in the `PROCINFO' array (*note +Auto-set::): + + PROCINFO["INPUT_NAME", "RETRY"] = 1 + + When this element exists, `gawk' checks the value of the system (C +language) `errno' variable when an I/O error occurs. If `errno' +indicates a subsequent I/O attempt may succeed, `getline' instead +returns -2 and further calls to `getline' may succeed. This applies to +the `errno' values `EAGAIN', `EWOULDBLOCK', `EINTR', or `ETIMEDOUT'. + + This feature is useful in conjunction with `PROCINFO["INPUT_NAME", +"READ_TIMEOUT"]' or situations where a file descriptor has been +configured to behave in a non-blocking fashion. + + +File: gawk.info, Node: Command-line directories, Next: Input Summary, Prev: Retrying Input, Up: Reading Files -4.11 Directories on the Command Line +4.12 Directories on the Command Line ==================================== According to the POSIX standard, files named on the `awk' command line @@ -6002,7 +6041,7 @@ usable data from an `awk' program. File: gawk.info, Node: Input Summary, Next: Input Exercises, Prev: Command-line directories, Up: Reading Files -4.12 Summary +4.13 Summary ============ * Input is split into records based on the value of `RS'. The @@ -6076,7 +6115,7 @@ File: gawk.info, Node: Input Summary, Next: Input Exercises, Prev: Command-li File: gawk.info, Node: Input Exercises, Prev: Input Summary, Up: Reading Files -4.13 Exercises +4.14 Exercises ============== 1. Using the `FIELDWIDTHS' variable (*note Constant Size::), write a @@ -6127,6 +6166,7 @@ function. `gawk' allows access to inherited file descriptors. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. @@ -7040,7 +7080,7 @@ that `gawk' provides: behavior. -File: gawk.info, Node: Close Files And Pipes, Next: Output Summary, Prev: Special Files, Up: Printing +File: gawk.info, Node: Close Files And Pipes, Next: Nonfatal, Prev: Special Files, Up: Printing 5.9 Closing Input and Output Redirections ========================================= @@ -7209,9 +7249,68 @@ call. See the system manual pages for information on how to decode this value. -File: gawk.info, Node: Output Summary, Next: Output Exercises, Prev: Close Files And Pipes, Up: Printing +File: gawk.info, Node: Nonfatal, Next: Output Summary, Prev: Close Files And Pipes, Up: Printing + +5.10 Enabling Nonfatal Output +============================= + +This minor node describes a `gawk'-specific feature. + + In standard `awk', output with `print' or `printf' to a nonexistent +file, or some other I/O error (such as filling up the disk) is a fatal +error. + + $ gawk 'BEGIN { print "hi" > "/no/such/file" }' + error--> gawk: cmd. line:1: fatal: can't redirect to `/no/such/file' (No such file or directory) + + `gawk' makes it possible to detect that an error has occurred, +allowing you to possibly recover from the error, or at least print an +error message of your choosing before exiting. You can do this in one +of two ways: + + * For all output files, by assigning any value to + `PROCINFO["NONFATAL"]'. + + * On a per-file basis, by assigning any value to `PROCINFO[FILENAME, + "NONFATAL"]'. Here, FILENAME is the name of the file to which you + wish output to be nonfatal. + + Once you have enabled nonfatal output, you must check `ERRNO' after +every relevant `print' or `printf' statement to see if something went +wrong. It is also a good idea to initialize `ERRNO' to zero before +attempting the output. For example: + + $ gawk ' + > BEGIN { + > PROCINFO["NONFATAL"] = 1 + > ERRNO = 0 + > print "hi" > "/no/such/file" + > if (ERRNO) { + > print("Output failed:", ERRNO) > "/dev/stderr" + > exit 1 + > } + > }' + error--> Output failed: No such file or directory + + Here, `gawk' did not produce a fatal error; instead it let the `awk' +program code detect the problem and handle it. + + This mechanism works also for standard output and standard error. +For standard output, you may use `PROCINFO["-", "NONFATAL"]' or +`PROCINFO["/dev/stdout", "NONFATAL"]'. For standard error, use +`PROCINFO["/dev/stderr", "NONFATAL"]'. + + When attempting to open a TCP/IP socket (*note TCP/IP Networking::), +`gawk' tries multiple times. The `GAWK_SOCK_RETRIES' environment +variable (*note Other Environment Variables::) allows you to override +`gawk''s builtin default number of attempts. However, once nonfatal +I/O is enabled for a given socket, `gawk' only retries once, relying on +`awk'-level code to notice that there was a problem. + + +File: gawk.info, Node: Output Summary, Next: Output Exercises, Prev: Nonfatal, Up: Printing -5.10 Summary +5.11 Summary ============ * The `print' statement prints comma-separated expressions. Each @@ -7233,11 +7332,16 @@ File: gawk.info, Node: Output Summary, Next: Output Exercises, Prev: Close Fi For coprocesses, it is possible to close only one direction of the communications. + * Normally errors with `print' or `printf' are fatal. `gawk' lets + you make output errors be nonfatal either for all files or on a + per-file basis. You must then check for errors after every + relevant output statement. + File: gawk.info, Node: Output Exercises, Prev: Output Summary, Up: Printing -5.11 Exercises +5.12 Exercises ============== 1. Rewrite the program: @@ -10332,10 +10436,24 @@ Options::), they are not special: An associative array containing the values of the environment. The array indices are the environment variable names; the elements are the values of the particular environment variables. For - example, `ENVIRON["HOME"]' might be `"/home/arnold"'. Changing - this array does not affect the environment passed on to any - programs that `awk' may spawn via redirection or the `system()' - function. (In a future version of `gawk', it may do so.) + example, `ENVIRON["HOME"]' might be `/home/arnold'. + + For POSIX `awk', changing this array does not affect the + environment passed on to any programs that `awk' may spawn via + redirection or the `system()' function. + + However, beginning with version 4.2, if not in POSIX compatibility + mode, `gawk' does update its own environment when `ENVIRON' is + changed, thus changing the environment seen by programs that it + creates. You should therefore be especially careful if you modify + `ENVIRON["PATH"]', which is the search path for finding executable + programs. + + This can also affect the running `gawk' program, since some of the + built-in functions may pay attention to certain environment + variables. The most notable instance of this is `mktime()' (*note + Time Functions::), which pays attention the value of the `TZ' + environment variable on many systems. Some operating systems may not have environment variables. On such systems, the `ENVIRON' array is empty (except for @@ -10358,6 +10476,11 @@ Options::), they are not special: `getline' returning -1. You are, of course, free to clear it yourself before doing an I/O operation. + If the value of `ERRNO' corresponds to a system error in the C + `errno' variable, then `PROCINFO["errno"]' will be set to the value + of `errno'. For non-system errors, `PROCINFO["errno"]' will be + zero. + `FILENAME' The name of the current input file. When no data files are listed on the command line, `awk' reads from the standard input and @@ -10406,6 +10529,10 @@ Options::), they are not special: `PROCINFO["egid"]' The value of the `getegid()' system call. + `PROCINFO["errno"]' + The value of the C `errno' variable when `ERRNO' is set to + the associated error message. + `PROCINFO["euid"]' The value of the `geteuid()' system call. @@ -10516,6 +10643,10 @@ Options::), they are not special: open input file, pipe, or coprocess. *Note Read Timeout::, for more information. + * It may be used to indicate that input may be retried when it + fails due to certain errors. *Note Retrying Input::, for + more information. + * It may be used to cause coprocesses to communicate over pseudo-ttys instead of through two-way pipes; this is discussed further in *note Two-way I/O::. @@ -11910,6 +12041,21 @@ brackets ([ ]): truncated toward zero. For example, `int(3)' is 3, `int(3.9)' is 3, `int(-3.9)' is -3, and `int(-3)' is -3 as well. +`intdiv(NUMERATOR, DENOMINATOR, RESULT)' + Perform integer division, similar to the standard C function of the + same name. First, truncate `numerator' and `denominator' towards + zero, creating integer values. Clear the `result' array, and then + set `result["quotient"]' to the result of `numerator / + denominator', truncated towards zero to an integer, and set + `result["remainder"]' to the result of `numerator % denominator', + truncated towards zero to an integer. This function is primarily + intended for use with arbitrary length integers; it avoids + creating MPFR arbitrary precision floating-point values (*note + Arbitrary Precision Integers::). + + This function is a `gawk' extension. It is not available in + compatibility mode (*note Options::). + `log(X)' Return the natural logarithm of X, if X is positive; otherwise, return `NaN' ("not a number") on IEEE 754 systems. Additionally, @@ -19912,8 +20058,7 @@ output. They are as follows: you typed when you wrote it. This is because `gawk' creates the profiled version by "pretty-printing" its internal representation of the program. The advantage to this is that `gawk' can produce a -standard representation. The disadvantage is that all source code -comments are lost. Also, things such as: +standard representation. Also, things such as: /foo/ @@ -19972,8 +20117,24 @@ the `Ctrl-\' key. called this way, `gawk' "pretty-prints" the program into `awkprof.out', without any execution counts. - NOTE: The `--pretty-print' option still runs your program. This - will change in the next major release. + NOTE: Once upon a time, the `--pretty-print' option would also run + your program. This is is no longer the case. + + There is a significant difference between the output created when +profiling, and that created when pretty-printing. Pretty-printed output +preserves the original comments that were in the program, although their +placement may not correspond exactly to their original locations in the +source code. + + However, as a deliberate design decision, profiling output _omits_ +the original program's comments. This allows you to focus on the +execution count data and helps you avoid the temptation to use the +profiler for pretty-printing. + + Additionally, pretty-printed output does not have the leading +indentation that the profiling output does. This makes it easy to +pretty-print your code once development is completed, and then use the +result as the final version of your program. File: gawk.info, Node: Advanced Features Summary, Prev: Profiling, Up: Advanced Features @@ -22453,6 +22614,63 @@ the following: gawk -M 'BEGIN { n = 13; print n % 2 }' + When dividing two arbitrary precision integers with either `/' or +`%', the result is typically an arbitrary precision floating point +value (unless the denominator evenly divides into the numerator). In +order to do integer division or remainder with arbitrary precision +integers, use the built-in `intdiv()' function (*note Numeric +Functions::). + + You can simulate the `intdiv()' function in standard `awk' using +this user-defined function: + + # intdiv --- do integer division + + function intdiv(numerator, denominator, result) + { + split("", result) + + numerator = int(numerator) + denominator = int(denominator) + result["quotient"] = int(numerator / denominator) + result["remainder"] = int(numerator % denominator) + + return 0.0 + } + + The following example program, contributed by Katie Wasserman, uses +`intdiv()' to compute the digits of pi to as many places as you choose +to set: + + # pi.awk --- compute the digits of pi + + BEGIN { + digits = 100000 + two = 2 * 10 ^ digits + pi = two + for (m = digits * 4; m > 0; --m) { + d = m * 2 + 1 + x = pi * m + intdiv(x, d, result) + pi = result["quotient"] + pi = pi + two + } + print pi + } + + When asked about the algorithm used, Katie replied: + + It's not that well known but it's not that obscure either. It's + Euler's modification to Newton's method for calculating pi. Take + a look at lines (23) - (25) here: + `http://mathworld.wolfram.com/PiFormulas.html'. + + The algorithm I wrote simply expands the multiply by 2 and works + from the innermost expression outwards. I used this to program HP + calculators because it's quite easy to modify for tiny memory + devices with smallish word sizes. See + `http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=899'. + ---------- Footnotes ---------- (1) Weisstein, Eric W. `Sylvester's Sequence'. From MathWorld--A @@ -22813,6 +23031,7 @@ describes the API in detail. * Symbol Table Access:: Functions for accessing global variables. * Array Manipulation:: Functions for working with arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension API Boilerplate:: Boilerplate code for using the API. @@ -22873,6 +23092,9 @@ operations: - Flattening an array for easy C-style looping over all its indices and elements + * Accessing and manipulating redirections. + + Some points about using the API: * The following types, macros, and/or functions are referenced in @@ -24084,7 +24306,7 @@ using `release_value()'. `double' to store. -File: gawk.info, Node: Array Manipulation, Next: Extension API Variables, Prev: Symbol Table Access, Up: Extension API Description +File: gawk.info, Node: Array Manipulation, Next: Redirection API, Prev: Symbol Table Access, Up: Extension API Description 16.4.11 Array Manipulation -------------------------- @@ -24569,9 +24791,78 @@ array: environment variable.) -File: gawk.info, Node: Extension API Variables, Next: Extension API Boilerplate, Prev: Array Manipulation, Up: Extension API Description +File: gawk.info, Node: Redirection API, Next: Extension API Variables, Prev: Array Manipulation, Up: Extension API Description + +16.4.12 Accessing and Manipulating Redirections +----------------------------------------------- + +The following function allows extensions to access and manipulate +redirections. + +`awk_bool_t get_file(const char *name,' +` size_t name_len,' +` const char *filetype,' +` int fd,' +` const awk_input_buf_t **ibufp,' +` const awk_output_buf_t **obufp);' + Look up a file in `gawk''s internal redirection table. If `name' + is `NULL' or `name_len' is zero, return data for the currently + open input file corresponding to `FILENAME'. (This does not + access the `filetype' argument, so that may be undefined). If the + file is not already open, attempt to open it. The `filetype' + argument must be zero-terminated and should be one of: + + `">"' + A file opened for output. + + `">>"' + A file opened for append. + + `"<"' + A file opened for input. + + `"|>"' + A pipe opened for output. + + `"|<"' + A pipe opened for input. + + `"|&"' + A two-way coprocess. + + On error, return a `false' value. Otherwise, return `true', and + return additional information about the redirection in the `ibufp' + and `obufp' pointers. For input redirections, the `*ibufp' value + should be non-`NULL', and `*obufp' should be `NULL'. For output + redirections, the `*obufp' value should be non-`NULL', and `*ibufp' + should be `NULL'. For two-way coprocesses, both values should be + non-`NULL'. + + In the usual case, the extension is interested in `(*ibufp)->fd' + and/or `fileno((*obufp)->fp)'. If the file is not already open, + and the `fd' argument is non-negative, `gawk' will use that file + descriptor instead of opening the file in the usual way. If `fd' + is non-negative, but the file exists already, `gawk' ignores `fd' + and returns the existing file. It is the caller's responsibility + to notice that neither the `fd' in the returned `awk_input_buf_t' + nor the `fd' in the returned `awk_output_buf_t' matches the + requested value. + + Note that supplying a file descriptor is currently _not_ supported + for pipes. However, supplying a file descriptor should work for + input, output, append, and two-way (coprocess) sockets. If + `filetype' is two-way, `gawk' assumes that it is a socket! Note + that in the two-way case, the input and output file descriptors + may differ. To check for success, you must check whether either + matches. + + It is anticipated that this API function will be used to implement +I/O multiplexing and a socket library. + + +File: gawk.info, Node: Extension API Variables, Next: Extension API Boilerplate, Prev: Redirection API, Up: Extension API Description -16.4.12 API Variables +16.4.13 API Variables --------------------- The API provides two sets of variables. The first provides information @@ -24588,7 +24879,7 @@ information about how `gawk' was invoked. File: gawk.info, Node: Extension Versioning, Next: Extension API Informational Variables, Up: Extension API Variables -16.4.12.1 API Version Constants and Variables +16.4.13.1 API Version Constants and Variables ............................................. The API provides both a "major" and a "minor" version number. The API @@ -24637,7 +24928,7 @@ Boilerplate::). File: gawk.info, Node: Extension API Informational Variables, Prev: Extension Versioning, Up: Extension API Variables -16.4.12.2 Informational Variables +16.4.13.2 Informational Variables ................................. The API provides access to several variables that describe whether the @@ -24672,7 +24963,7 @@ not change during execution. File: gawk.info, Node: Extension API Boilerplate, Prev: Extension API Variables, Up: Extension API Description -16.4.13 Boilerplate Code +16.4.14 Boilerplate Code ------------------------ As mentioned earlier (*note Extension Mechanism Outline::), the function @@ -25977,15 +26268,17 @@ project. * GD graphics library extension + * MPFR library extension (this provides access to a number of MPFR + functions that `gawk''s native MPFR support does not) + * PDF extension * PostgreSQL extension - * MPFR library extension (this provides access to a number of MPFR - functions that `gawk''s native MPFR support does not) - * Redis extension + * Select extension + * XML parser extension, using the Expat (http://expat.sourceforge.net) XML parsing library @@ -26402,6 +26695,9 @@ the current version of `gawk'. - Directories on the command line produce a warning and are skipped (*note Command-line directories::) + - Output with `print' and `printf' need not be fatal (*note + Nonfatal::) + * New keywords: - The `BEGINFILE' and `ENDFILE' special patterns (*note @@ -26451,6 +26747,9 @@ the current version of `gawk'. - The `bindtextdomain()', `dcgettext()', and `dcngettext()' functions for internationalization (*note Programmer i18n::) + - The `intdiv()' function for doing integer division and + remainder (*note Numeric Functions::) + * Changes and/or additions in the command-line options: - The `AWKPATH' environment variable for specifying a path @@ -26505,6 +26804,11 @@ the current version of `gawk'. - Ultrix + * Support for the following systems was removed from the code for + `gawk' version 4.2: + + - MirBSD + File: gawk.info, Node: Feature History, Next: Common Extensions, Prev: POSIX/GNU, Up: Language History @@ -26896,6 +27200,28 @@ in POSIX `awk', in the order they were added to `gawk'. * The `where' command was added to the debugger (*note Execution Stack::). + * Support for Ultrix was removed. + + + Version 4.2 introduced the following changes: + + * Changes to `ENVIRON' are reflected into `gawk''s environment and + that of programs that it runs. *Note Auto-set::. + + * The `--pretty-print' option no longer runs the `awk' program too. + *Note Options::. + + * The `igawk' program and its manual page are no longer installed + when `gawk' is built. *Note Igawk Program::. + + * The `intdiv()' function. *Note Numeric Functions::. + + * The maximum number of hexdecimal digits in `\x' escapes is now two. + *Note Escape Sequences::. + + * Nonfatal output with `print' and `printf'. *Note Nonfatal::. + + * Support for MirBSD was removed. File: gawk.info, Node: Common Extensions, Next: Ranges and Locales, Prev: Feature History, Up: Language History @@ -27413,7 +27739,9 @@ Various `.c', `.y', and `.h' files `doc/igawk.1' The `troff' source for a manual page describing the `igawk' - program presented in *note Igawk Program::. + program presented in *note Igawk Program::. (Since `gawk' can do + its own `@include' processing, neither `igawk' nor `igawk.1' are + installed.) `doc/Makefile.in' The input file used during the configuration process to generate @@ -27455,17 +27783,23 @@ Various `.c', `.y', and `.h' files contains a `Makefile.in' file, which `configure' uses to generate a `Makefile'. `Makefile.am' is used by GNU Automake to create `Makefile.in'. The library functions from *note Library - Functions::, and the `igawk' program from *note Igawk Program::, - are included as ready-to-use files in the `gawk' distribution. - They are installed as part of the installation process. The rest - of the programs in this Info file are available in appropriate - subdirectories of `awklib/eg'. + Functions::, are included as ready-to-use files in the `gawk' + distribution. They are installed as part of the installation + process. The rest of the programs in this Info file are available + in appropriate subdirectories of `awklib/eg'. `extension/*' The source code, manual pages, and infrastructure files for the sample extensions included with `gawk'. *Note Dynamic Extensions::, for more information. +`extras/*' + Additional non-essential files. Currently, this directory + contains some shell startup files to be installed in + `/etc/profile.d' to aid in manipulating the `AWKPATH' and + `AWKLIBPATH' environment variables. *Note Shell Startup Files::, + for more information. + `posix/*' Files needed for building `gawk' on POSIX-compliant systems. @@ -27496,11 +27830,12 @@ configure `gawk' for your system yourself. * Menu: * Quick Installation:: Compiling `gawk' under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. -File: gawk.info, Node: Quick Installation, Next: Additional Configuration Options, Up: Unix Installation +File: gawk.info, Node: Quick Installation, Next: Shell Startup Files, Up: Unix Installation B.2.1 Compiling `gawk' for Unix-Like Systems -------------------------------------------- @@ -27556,9 +27891,43 @@ will be asked for your password, and you will have to have been set up previously as a user who is allowed to run the `sudo' command. -File: gawk.info, Node: Additional Configuration Options, Next: Configuration Philosophy, Prev: Quick Installation, Up: Unix Installation +File: gawk.info, Node: Shell Startup Files, Next: Additional Configuration Options, Prev: Quick Installation, Up: Unix Installation + +B.2.2 Shell Startup Files +------------------------- + +The distribution contains shell startup files `gawk.sh' and `gawk.csh' +containing functions to aid in manipulating the `AWKPATH' and +`AWKLIBPATH' environment variables. On a Fedora system, these files +should be installed in `/etc/profile.d'; on other platforms, the +appropriate location may be different. + +`gawkpath_default' + Reset the `AWKPATH' environment variable to its default value. + +`gawkpath_prepend' + Add the argument to the front of the `AWKPATH' environment + variable. + +`gawkpath_append' + Add the argument to the end of the `AWKPATH' environment variable. + +`gawklibpath_default' + Reset the `AWKLIBPATH' environment variable to its default value. + +`gawklibpath_prepend' + Add the argument to the front of the `AWKLIBPATH' environment + variable. + +`gawklibpath_append' + Add the argument to the end of the `AWKLIBPATH' environment + variable. + + + +File: gawk.info, Node: Additional Configuration Options, Next: Configuration Philosophy, Prev: Shell Startup Files, Up: Unix Installation -B.2.2 Additional Configuration Options +B.2.3 Additional Configuration Options -------------------------------------- There are several additional options you may use on the `configure' @@ -27602,7 +27971,7 @@ supplied by `configure'. File: gawk.info, Node: Configuration Philosophy, Prev: Additional Configuration Options, Up: Unix Installation -B.2.3 The Configuration Process +B.2.4 The Configuration Process ------------------------------- This minor node is of interest only if you know something about using @@ -31554,20 +31923,20 @@ Index * --include option: Options. (line 159) * --lint option <1>: Options. (line 185) * --lint option: Command Line. (line 20) -* --lint-old option: Options. (line 297) +* --lint-old option: Options. (line 295) * --load option: Options. (line 173) * --non-decimal-data option <1>: Nondecimal Data. (line 6) * --non-decimal-data option: Options. (line 211) * --non-decimal-data option, strtonum() function and: Nondecimal Data. (line 35) -* --optimize option: Options. (line 238) -* --posix option: Options. (line 256) -* --posix option, --traditional option and: Options. (line 275) +* --optimize option: Options. (line 236) +* --posix option: Options. (line 254) +* --posix option, --traditional option and: Options. (line 273) * --pretty-print option: Options. (line 225) * --profile option <1>: Profiling. (line 12) -* --profile option: Options. (line 244) -* --re-interval option: Options. (line 281) -* --sandbox option: Options. (line 288) +* --profile option: Options. (line 242) +* --re-interval option: Options. (line 279) +* --sandbox option: Options. (line 286) * --sandbox option, disabling system() function: I/O Functions. (line 129) * --sandbox option, input redirection with getline: Getline. (line 19) @@ -31575,9 +31944,9 @@ Index (line 6) * --source option: Options. (line 117) * --traditional option: Options. (line 81) -* --traditional option, --posix option and: Options. (line 275) +* --traditional option, --posix option and: Options. (line 273) * --use-lc-numeric option: Options. (line 220) -* --version option: Options. (line 302) +* --version option: Options. (line 300) * --with-whiny-user-strftime configuration option: Additional Configuration Options. (line 37) * -b option: Options. (line 68) @@ -31585,32 +31954,32 @@ Index * -c option: Options. (line 81) * -D option: Options. (line 108) * -d option: Options. (line 93) -* -e option: Options. (line 338) +* -e option: Options. (line 336) * -E option: Options. (line 125) * -e option: Options. (line 117) * -f option: Options. (line 25) * -F option: Options. (line 21) * -f option: Long. (line 12) -* -F option, -Ft sets FS to TAB: Options. (line 310) +* -F option, -Ft sets FS to TAB: Options. (line 308) * -F option, command-line: Command Line Field Separator. (line 6) -* -f option, multiple uses: Options. (line 315) +* -f option, multiple uses: Options. (line 313) * -g option: Options. (line 147) * -h option: Options. (line 154) * -i option: Options. (line 159) -* -L option: Options. (line 297) +* -L option: Options. (line 295) * -l option: Options. (line 173) * -M option: Options. (line 205) * -N option: Options. (line 220) * -n option: Options. (line 211) -* -O option: Options. (line 238) +* -O option: Options. (line 236) * -o option: Options. (line 225) -* -P option: Options. (line 256) -* -p option: Options. (line 244) -* -r option: Options. (line 281) -* -S option: Options. (line 288) +* -P option: Options. (line 254) +* -p option: Options. (line 242) +* -r option: Options. (line 279) +* -S option: Options. (line 286) * -v option: Assignment Options. (line 12) -* -V option: Options. (line 302) +* -V option: Options. (line 300) * -v option: Options. (line 32) * -W option: Options. (line 46) * . (period), regexp operator: Regexp Operators. (line 44) @@ -31672,10 +32041,10 @@ Index (line 8) * [] (square brackets), regexp operator: Regexp Operators. (line 56) * \ (backslash): Comments. (line 50) -* \ (backslash), \" escape sequence: Escape Sequences. (line 82) +* \ (backslash), \" escape sequence: Escape Sequences. (line 85) * \ (backslash), \' operator (gawk): GNU Regexp Operators. (line 56) -* \ (backslash), \/ escape sequence: Escape Sequences. (line 73) +* \ (backslash), \/ escape sequence: Escape Sequences. (line 76) * \ (backslash), \< operator (gawk): GNU Regexp Operators. (line 30) * \ (backslash), \> operator (gawk): GNU Regexp Operators. @@ -31715,7 +32084,7 @@ Index * \ (backslash), in bracket expressions: Bracket Expressions. (line 17) * \ (backslash), in escape sequences: Escape Sequences. (line 6) * \ (backslash), in escape sequences, POSIX and: Escape Sequences. - (line 105) + (line 108) * \ (backslash), in regexp constants: Computed Regexps. (line 30) * \ (backslash), in shell commands: Quoting. (line 48) * \ (backslash), regexp operator: Regexp Operators. (line 18) @@ -31883,7 +32252,7 @@ Index * awf (amazingly workable formatter) program: Glossary. (line 24) * awk debugging, enabling: Options. (line 108) * awk language, POSIX version: Assignment Ops. (line 137) -* awk profiling, enabling: Options. (line 244) +* awk profiling, enabling: Options. (line 242) * awk programs <1>: Two Rules. (line 6) * awk programs <2>: Executable Scripts. (line 6) * awk programs: Getting Started. (line 12) @@ -31941,10 +32310,10 @@ Index * awkvars.out file: Options. (line 93) * b debugger command (alias for break): Breakpoint Control. (line 11) * backslash (\): Comments. (line 50) -* backslash (\), \" escape sequence: Escape Sequences. (line 82) +* backslash (\), \" escape sequence: Escape Sequences. (line 85) * backslash (\), \' operator (gawk): GNU Regexp Operators. (line 56) -* backslash (\), \/ escape sequence: Escape Sequences. (line 73) +* backslash (\), \/ escape sequence: Escape Sequences. (line 76) * backslash (\), \< operator (gawk): GNU Regexp Operators. (line 30) * backslash (\), \> operator (gawk): GNU Regexp Operators. @@ -31984,7 +32353,7 @@ Index * backslash (\), in bracket expressions: Bracket Expressions. (line 17) * backslash (\), in escape sequences: Escape Sequences. (line 6) * backslash (\), in escape sequences, POSIX and: Escape Sequences. - (line 105) + (line 108) * backslash (\), in regexp constants: Computed Regexps. (line 30) * backslash (\), in shell commands: Quoting. (line 48) * backslash (\), regexp operator: Regexp Operators. (line 18) @@ -32090,7 +32459,7 @@ Index (line 67) * Brian Kernighan's awk <12>: GNU Regexp Operators. (line 82) -* Brian Kernighan's awk <13>: Escape Sequences. (line 109) +* Brian Kernighan's awk <13>: Escape Sequences. (line 112) * Brian Kernighan's awk: When. (line 21) * Brian Kernighan's awk, extensions: BTL. (line 6) * Brian Kernighan's awk, source code: Other Versions. (line 13) @@ -32284,7 +32653,7 @@ Index * cosine: Numeric Functions. (line 15) * counting: Wc Program. (line 6) * csh utility: Statements/Lines. (line 44) -* csh utility, POSIXLY_CORRECT environment variable: Options. (line 356) +* csh utility, POSIXLY_CORRECT environment variable: Options. (line 354) * csh utility, |& operator, comparison with: Two-way I/O. (line 25) * ctime() user-defined function: Function Example. (line 74) * currency symbols, localization: Explaining gettext. (line 104) @@ -32315,12 +32684,12 @@ Index * dark corner, CONVFMT variable: Strings And Numbers. (line 40) * dark corner, escape sequences: Other Arguments. (line 38) * dark corner, escape sequences, for metacharacters: Escape Sequences. - (line 140) + (line 143) * dark corner, exit statement: Exit Statement. (line 30) * dark corner, field separators: Full Line Fields. (line 22) -* dark corner, FILENAME variable <1>: Auto-set. (line 90) +* dark corner, FILENAME variable <1>: Auto-set. (line 109) * dark corner, FILENAME variable: Getline Notes. (line 19) -* dark corner, FNR/NR variables: Auto-set. (line 314) +* dark corner, FNR/NR variables: Auto-set. (line 341) * dark corner, format-control characters: Control Letters. (line 18) * dark corner, FS as null string: Single Character Fields. (line 20) @@ -32470,7 +32839,7 @@ Index * debugger, read commands from a file: Debugger Info. (line 97) * debugging awk programs: Debugger. (line 6) * debugging gawk, bug reports: Bugs. (line 9) -* decimal point character, locale specific: Options. (line 272) +* decimal point character, locale specific: Options. (line 270) * decrement operators: Increment Ops. (line 35) * default keyword: Switch Statement. (line 6) * Deifik, Scott <1>: Bugs. (line 71) @@ -32509,12 +32878,12 @@ Index (line 81) * differences in awk and gawk, command-line directories: Command-line directories. (line 6) -* differences in awk and gawk, ERRNO variable: Auto-set. (line 74) +* differences in awk and gawk, ERRNO variable: Auto-set. (line 88) * differences in awk and gawk, error messages: Special FD. (line 19) * differences in awk and gawk, FIELDWIDTHS variable: User-modified. (line 37) * differences in awk and gawk, FPAT variable: User-modified. (line 43) -* differences in awk and gawk, FUNCTAB variable: Auto-set. (line 116) +* differences in awk and gawk, FUNCTAB variable: Auto-set. (line 135) * differences in awk and gawk, function arguments (gawk): Calling Built-in. (line 16) * differences in awk and gawk, getline command: Getline. (line 19) @@ -32537,7 +32906,7 @@ Index (line 263) * differences in awk and gawk, print/printf statements: Format Modifiers. (line 13) -* differences in awk and gawk, PROCINFO array: Auto-set. (line 130) +* differences in awk and gawk, PROCINFO array: Auto-set. (line 149) * differences in awk and gawk, read timeouts: Read Timeout. (line 6) * differences in awk and gawk, record separators: awk split records. (line 125) @@ -32545,9 +32914,11 @@ Index (line 43) * differences in awk and gawk, regular expressions: Case-sensitivity. (line 26) +* differences in awk and gawk, retrying input: Retrying Input. + (line 6) * differences in awk and gawk, RS/RT variables: gawk split records. (line 58) -* differences in awk and gawk, RT variable: Auto-set. (line 265) +* differences in awk and gawk, RT variable: Auto-set. (line 292) * differences in awk and gawk, single-character fields: Single Character Fields. (line 6) * differences in awk and gawk, split() function: String Functions. @@ -32555,7 +32926,7 @@ Index * differences in awk and gawk, strings: Scalar Constants. (line 20) * differences in awk and gawk, strings, storing: gawk split records. (line 77) -* differences in awk and gawk, SYMTAB variable: Auto-set. (line 269) +* differences in awk and gawk, SYMTAB variable: Auto-set. (line 296) * differences in awk and gawk, TEXTDOMAIN variable: User-modified. (line 151) * differences in awk and gawk, trunc-mod operation: Arithmetic Ops. @@ -32591,12 +32962,12 @@ Index * dump debugger command: Miscellaneous Debugger Commands. (line 9) * dupword.awk program: Dupword Program. (line 31) -* dynamic profiling: Profiling. (line 179) +* dynamic profiling: Profiling. (line 178) * dynamically loaded extensions: Dynamic Extensions. (line 6) * e debugger command (alias for enable): Breakpoint Control. (line 73) * EBCDIC: Ordinal Functions. (line 45) -* effective group ID of gawk user: Auto-set. (line 135) -* effective user ID of gawk user: Auto-set. (line 139) +* effective group ID of gawk user: Auto-set. (line 154) +* effective user ID of gawk user: Auto-set. (line 162) * egrep utility <1>: Egrep Program. (line 6) * egrep utility: Bracket Expressions. (line 26) * egrep.awk program: Egrep Program. (line 54) @@ -32651,13 +33022,13 @@ Index (line 11) * EREs (Extended Regular Expressions): Bracket Expressions. (line 26) * ERRNO variable <1>: TCP/IP Networking. (line 54) -* ERRNO variable: Auto-set. (line 74) +* ERRNO variable: Auto-set. (line 88) * ERRNO variable, with BEGINFILE pattern: BEGINFILE/ENDFILE. (line 26) * ERRNO variable, with close() function: Close Files And Pipes. (line 141) * ERRNO variable, with getline command: Getline. (line 19) * error handling: Special FD. (line 19) -* error handling, ERRNO variable and: Auto-set. (line 74) +* error handling, ERRNO variable and: Auto-set. (line 88) * error output: Special FD. (line 6) * escape processing, gsub()/gensub()/sub() functions: Gory Details. (line 6) @@ -32692,7 +33063,7 @@ Index (line 99) * exp: Numeric Functions. (line 18) * expand utility: Very Simple. (line 73) -* Expat XML parser library: gawkextlib. (line 35) +* Expat XML parser library: gawkextlib. (line 37) * exponent: Numeric Functions. (line 18) * expressions: Expressions. (line 6) * expressions, as patterns: Expression Patterns. (line 6) @@ -32711,7 +33082,7 @@ Index (line 6) * extension API version: Extension Versioning. (line 6) -* extension API, version number: Auto-set. (line 232) +* extension API, version number: Auto-set. (line 255) * extension example: Extension Example. (line 6) * extension registration: Registration Functions. (line 6) @@ -32792,7 +33163,7 @@ Index * file names, distinguishing: Auto-set. (line 56) * file names, in compatibility mode: Special Caveats. (line 9) * file names, standard streams in gawk: Special FD. (line 48) -* FILENAME variable <1>: Auto-set. (line 90) +* FILENAME variable <1>: Auto-set. (line 109) * FILENAME variable: Reading Files. (line 6) * FILENAME variable, getline, setting with: Getline Notes. (line 19) * filenames, assignments as: Ignoring Assigns. (line 6) @@ -32860,9 +33231,9 @@ Index * flush buffered output: I/O Functions. (line 28) * fnmatch() extension function: Extension Sample Fnmatch. (line 12) -* FNR variable <1>: Auto-set. (line 100) +* FNR variable <1>: Auto-set. (line 119) * FNR variable: Records. (line 6) -* FNR variable, changing: Auto-set. (line 314) +* FNR variable, changing: Auto-set. (line 341) * for statement: For Statement. (line 6) * for statement, looping over arrays: Scanning an Array. (line 20) * fork() extension function: Extension Sample Fork. @@ -32899,7 +33270,7 @@ Index * FS variable, --field-separator option and: Options. (line 21) * FS variable, as null string: Single Character Fields. (line 20) -* FS variable, as TAB character: Options. (line 268) +* FS variable, as TAB character: Options. (line 266) * FS variable, changing value of: Field Separators. (line 35) * FS variable, running awk programs and: Cut Program. (line 63) * FS variable, setting from command line: Command Line Field Separator. @@ -32912,7 +33283,7 @@ Index * FSF (Free Software Foundation): Manual History. (line 6) * fts() extension function: Extension Sample File Functions. (line 61) -* FUNCTAB array: Auto-set. (line 116) +* FUNCTAB array: Auto-set. (line 135) * function calls: Function Calls. (line 6) * function calls, indirect: Indirect Calls. (line 6) * function calls, indirect, @-notation for: Indirect Calls. (line 47) @@ -32961,8 +33332,8 @@ Index (line 44) * G-d: Acknowledgments. (line 94) * Garfinkle, Scott: Contributors. (line 34) -* gawk program, dynamic profiling: Profiling. (line 179) -* gawk version: Auto-set. (line 207) +* gawk program, dynamic profiling: Profiling. (line 178) +* gawk version: Auto-set. (line 230) * gawk, ARGIND variable in: Other Arguments. (line 15) * gawk, awk and <1>: This Manual. (line 14) * gawk, awk and: Preface. (line 21) @@ -32980,13 +33351,13 @@ Index * gawk, distribution: Distribution contents. (line 6) * gawk, ERRNO variable in <1>: TCP/IP Networking. (line 54) -* gawk, ERRNO variable in <2>: Auto-set. (line 74) +* gawk, ERRNO variable in <2>: Auto-set. (line 88) * gawk, ERRNO variable in <3>: BEGINFILE/ENDFILE. (line 26) * gawk, ERRNO variable in <4>: Close Files And Pipes. (line 141) * gawk, ERRNO variable in: Getline. (line 19) -* gawk, escape sequences: Escape Sequences. (line 117) -* gawk, extensions, disabling: Options. (line 256) +* gawk, escape sequences: Escape Sequences. (line 120) +* gawk, extensions, disabling: Options. (line 254) * gawk, features, adding: Adding Code. (line 6) * gawk, features, advanced: Advanced Features. (line 6) * gawk, field separators and: User-modified. (line 71) @@ -32997,7 +33368,7 @@ Index * gawk, FPAT variable in <1>: User-modified. (line 43) * gawk, FPAT variable in: Splitting By Content. (line 25) -* gawk, FUNCTAB array in: Auto-set. (line 116) +* gawk, FUNCTAB array in: Auto-set. (line 135) * gawk, function arguments and: Calling Built-in. (line 16) * gawk, hexadecimal numbers and: Nondecimal-numbers. (line 42) * gawk, IGNORECASE variable in <1>: Array Sorting Functions. @@ -33029,7 +33400,7 @@ Index * gawk, predefined variables and: Built-in Variables. (line 14) * gawk, PROCINFO array in <1>: Two-way I/O. (line 99) * gawk, PROCINFO array in <2>: Time Functions. (line 47) -* gawk, PROCINFO array in: Auto-set. (line 130) +* gawk, PROCINFO array in: Auto-set. (line 149) * gawk, regexp constants and: Using Constant Regexps. (line 28) * gawk, regular expressions, case sensitivity: Case-sensitivity. @@ -33037,23 +33408,29 @@ Index * gawk, regular expressions, operators: GNU Regexp Operators. (line 6) * gawk, regular expressions, precedence: Regexp Operators. (line 161) -* gawk, RT variable in <1>: Auto-set. (line 265) +* gawk, RT variable in <1>: Auto-set. (line 292) * gawk, RT variable in <2>: Multiple Line. (line 129) * gawk, RT variable in: awk split records. (line 125) * gawk, See Also awk: Preface. (line 34) * gawk, source code, obtaining: Getting. (line 6) * gawk, splitting fields and: Constant Size. (line 87) * gawk, string-translation functions: I18N Functions. (line 6) -* gawk, SYMTAB array in: Auto-set. (line 269) +* gawk, SYMTAB array in: Auto-set. (line 296) * gawk, TEXTDOMAIN variable in: User-modified. (line 151) * gawk, timestamps: Time Functions. (line 6) * gawk, uses for: Preface. (line 34) -* gawk, versions of, information about, printing: Options. (line 302) +* gawk, versions of, information about, printing: Options. (line 300) * gawk, VMS version of: VMS Installation. (line 6) * gawk, word-boundary operator: GNU Regexp Operators. (line 63) * gawkextlib: gawkextlib. (line 6) * gawkextlib project: gawkextlib. (line 6) +* gawklibpath_append shell function: Shell Startup Files. (line 29) +* gawklibpath_default shell function: Shell Startup Files. (line 22) +* gawklibpath_prepend shell function: Shell Startup Files. (line 25) +* gawkpath_append shell function: Shell Startup Files. (line 19) +* gawkpath_default shell function: Shell Startup Files. (line 12) +* gawkpath_prepend shell function: Shell Startup Files. (line 15) * General Public License (GPL): Glossary. (line 399) * General Public License, See GPL: Manual History. (line 11) * generate time values: Time Functions. (line 25) @@ -33106,7 +33483,7 @@ Index * git utility <2>: Accessing The Source. (line 10) * git utility <3>: Other Versions. (line 29) -* git utility: gawkextlib. (line 29) +* git utility: gawkextlib. (line 31) * Git, use of for gawk source code: Derived Files. (line 6) * GNITS mailing list: Acknowledgments. (line 52) * GNU awk, See gawk: Preface. (line 51) @@ -33130,7 +33507,7 @@ Index * Grigera, Juan: Contributors. (line 57) * group database, reading: Group Functions. (line 6) * group file: Group Functions. (line 6) -* group ID of gawk user: Auto-set. (line 180) +* group ID of gawk user: Auto-set. (line 203) * groups, information about: Group Functions. (line 6) * gsub <1>: String Functions. (line 140) * gsub: Using Constant Regexps. @@ -33152,7 +33529,7 @@ Index * history expansion, in debugger: Readline Support. (line 6) * histsort.awk program: History Sorting. (line 25) * Hughes, Phil: Acknowledgments. (line 43) -* HUP signal, for dynamic profiling: Profiling. (line 211) +* HUP signal, for dynamic profiling: Profiling. (line 210) * hyphen (-), - operator: Precedence. (line 52) * hyphen (-), -- operator <1>: Precedence. (line 46) * hyphen (-), -- operator: Increment Ops. (line 48) @@ -33232,7 +33609,8 @@ Index * installing gawk: Installation. (line 6) * instruction tracing, in debugger: Debugger Info. (line 90) * int: Numeric Functions. (line 23) -* INT signal (MS-Windows): Profiling. (line 214) +* INT signal (MS-Windows): Profiling. (line 213) +* intdiv: Numeric Functions. (line 28) * integer array indices: Numeric Array Subscripts. (line 31) * integers, arbitrary precision: Arbitrary Precision Integers. @@ -33288,7 +33666,7 @@ Index * Kernighan, Brian <9>: Acknowledgments. (line 78) * Kernighan, Brian <10>: Conventions. (line 38) * Kernighan, Brian: History. (line 17) -* kill command, dynamic profiling: Profiling. (line 188) +* kill command, dynamic profiling: Profiling. (line 187) * Knights, jedi: Undocumented. (line 6) * Kwok, Conrad: Contributors. (line 34) * l debugger command (alias for list): Miscellaneous Debugger Commands. @@ -33360,7 +33738,7 @@ Index * lint checking, empty programs: Command Line. (line 16) * lint checking, issuing warnings: Options. (line 185) * lint checking, POSIXLY_CORRECT environment variable: Options. - (line 341) + (line 339) * lint checking, undefined functions: Pass By Value/Reference. (line 85) * LINT variable: User-modified. (line 87) @@ -33376,14 +33754,14 @@ Index * loading, extensions: Options. (line 173) * local variables, in a function: Variable Scope. (line 6) * locale categories: Explaining gettext. (line 81) -* locale decimal point character: Options. (line 272) +* locale decimal point character: Options. (line 270) * locale, definition of: Locales. (line 6) * localization: I18N and L10N. (line 6) * localization, See internationalization, localization: I18N and L10N. (line 6) -* log: Numeric Functions. (line 28) +* log: Numeric Functions. (line 43) * log files, timestamps in: Time Functions. (line 6) -* logarithm: Numeric Functions. (line 28) +* logarithm: Numeric Functions. (line 43) * logical false/true: Truth Values. (line 6) * logical operators, See Boolean expressions: Boolean Ops. (line 6) * login information: Passwd Functions. (line 16) @@ -33424,8 +33802,8 @@ Index * mawk utility <2>: Nextfile Statement. (line 47) * mawk utility <3>: Concatenation. (line 36) * mawk utility <4>: Getline/Pipe. (line 62) -* mawk utility: Escape Sequences. (line 117) -* maximum precision supported by MPFR library: Auto-set. (line 221) +* mawk utility: Escape Sequences. (line 120) +* maximum precision supported by MPFR library: Auto-set. (line 244) * McIlroy, Doug: Glossary. (line 258) * McPhee, Patrick: Contributors. (line 100) * message object files: Explaining gettext. (line 42) @@ -33437,8 +33815,8 @@ Index (line 54) * messages from extensions: Printing Messages. (line 6) * metacharacters in regular expressions: Regexp Operators. (line 6) -* metacharacters, escape sequences for: Escape Sequences. (line 136) -* minimum precision required by MPFR library: Auto-set. (line 224) +* metacharacters, escape sequences for: Escape Sequences. (line 139) +* minimum precision required by MPFR library: Auto-set. (line 247) * mktime: Time Functions. (line 25) * modifiers, in format specifiers: Format Modifiers. (line 6) * monetary information, localization: Explaining gettext. (line 104) @@ -33458,7 +33836,7 @@ Index * networks, programming: TCP/IP Networking. (line 6) * networks, support for: Special Network. (line 6) * newlines <1>: Boolean Ops. (line 69) -* newlines <2>: Options. (line 262) +* newlines <2>: Options. (line 260) * newlines: Statements/Lines. (line 6) * newlines, as field separators: Default Field Splitting. (line 6) @@ -33487,7 +33865,7 @@ Index (line 47) * nexti debugger command: Debugger Execution Control. (line 49) -* NF variable <1>: Auto-set. (line 105) +* NF variable <1>: Auto-set. (line 124) * NF variable: Fields. (line 33) * NF variable, decrementing: Changing Fields. (line 107) * ni debugger command (alias for nexti): Debugger Execution Control. @@ -33496,9 +33874,9 @@ Index * non-existent array elements: Reference to Elements. (line 23) * not Boolean-logic operator: Boolean Ops. (line 6) -* NR variable <1>: Auto-set. (line 125) +* NR variable <1>: Auto-set. (line 144) * NR variable: Records. (line 6) -* NR variable, changing: Auto-set. (line 314) +* NR variable, changing: Auto-set. (line 341) * null strings <1>: Basic Data Typing. (line 26) * null strings <2>: Truth Values. (line 6) * null strings <3>: Regexp Field Splitting. @@ -33612,7 +33990,7 @@ Index * p debugger command (alias for print): Viewing And Changing Data. (line 36) * Papadopoulos, Panos: Contributors. (line 128) -* parent process ID of gawk process: Auto-set. (line 189) +* parent process ID of gawk process: Auto-set. (line 212) * parentheses (), in a profile: Profiling. (line 146) * parentheses (), regexp operator: Regexp Operators. (line 81) * password file: Passwd Functions. (line 16) @@ -33654,14 +34032,14 @@ Index * plus sign (+), += operator: Assignment Ops. (line 82) * plus sign (+), regexp operator: Regexp Operators. (line 105) * pointers to functions: Indirect Calls. (line 6) -* portability: Escape Sequences. (line 100) +* portability: Escape Sequences. (line 103) * portability, #! (executable scripts): Executable Scripts. (line 33) * portability, ** operator and: Arithmetic Ops. (line 81) * portability, **= operator and: Assignment Ops. (line 143) * portability, ARGV variable: Executable Scripts. (line 59) * portability, backslash continuation and: Statements/Lines. (line 30) * portability, backslash in escape sequences: Escape Sequences. - (line 105) + (line 108) * portability, close() function and: Close Files And Pipes. (line 81) * portability, data files as single record: gawk split records. @@ -33679,7 +34057,7 @@ Index * portability, NF variable, decrementing: Changing Fields. (line 115) * portability, operators: Increment Ops. (line 60) * portability, operators, not in POSIX awk: Precedence. (line 98) -* portability, POSIXLY_CORRECT environment variable: Options. (line 361) +* portability, POSIXLY_CORRECT environment variable: Options. (line 359) * portability, substr() function: String Functions. (line 513) * portable object files <1>: Translator i18n. (line 6) * portable object files: Explaining gettext. (line 37) @@ -33700,7 +34078,7 @@ Index * POSIX awk, < operator and: Getline/File. (line 26) * POSIX awk, arithmetic operators and: Arithmetic Ops. (line 30) * POSIX awk, backslashes in string constants: Escape Sequences. - (line 105) + (line 108) * POSIX awk, BEGIN/END patterns: I/O And BEGIN/END. (line 16) * POSIX awk, bracket expressions and: Bracket Expressions. (line 26) * POSIX awk, bracket expressions and, character classes: Bracket Expressions. @@ -33727,11 +34105,11 @@ Index * POSIX awk, regular expressions and: Regexp Operators. (line 161) * POSIX awk, timestamps and: Time Functions. (line 6) * POSIX awk, | I/O operator and: Getline/Pipe. (line 55) -* POSIX mode: Options. (line 256) +* POSIX mode: Options. (line 254) * POSIX, awk and: Preface. (line 21) * POSIX, gawk extensions not included in: POSIX/GNU. (line 6) * POSIX, programs, implementing in awk: Clones. (line 6) -* POSIXLY_CORRECT environment variable: Options. (line 341) +* POSIXLY_CORRECT environment variable: Options. (line 339) * PREC variable: User-modified. (line 123) * precedence <1>: Precedence. (line 6) * precedence: Increment Ops. (line 60) @@ -33778,24 +34156,24 @@ Index * printing, unduplicated lines of text: Uniq Program. (line 6) * printing, user information: Id Program. (line 6) * private variables: Library Names. (line 11) -* process group ID of gawk process: Auto-set. (line 183) -* process ID of gawk process: Auto-set. (line 186) +* process group ID of gawk process: Auto-set. (line 206) +* process ID of gawk process: Auto-set. (line 209) * processes, two-way communications with: Two-way I/O. (line 6) * processing data: Basic High Level. (line 6) * PROCINFO array <1>: Passwd Functions. (line 6) * PROCINFO array <2>: Time Functions. (line 47) -* PROCINFO array: Auto-set. (line 130) +* PROCINFO array: Auto-set. (line 149) * PROCINFO array, and communications via ptys: Two-way I/O. (line 99) * PROCINFO array, and group membership: Group Functions. (line 6) * PROCINFO array, and user and group ID numbers: Id Program. (line 15) * PROCINFO array, testing the field splitting: Passwd Functions. (line 154) -* PROCINFO array, uses: Auto-set. (line 242) +* PROCINFO array, uses: Auto-set. (line 265) * PROCINFO, values of sorted_in: Controlling Scanning. (line 26) * profiling awk programs: Profiling. (line 6) -* profiling awk programs, dynamically: Profiling. (line 179) -* program identifiers: Auto-set. (line 148) +* profiling awk programs, dynamically: Profiling. (line 178) +* program identifiers: Auto-set. (line 171) * program, definition of: Getting Started. (line 21) * programming conventions, --non-decimal-data option: Nondecimal Data. (line 35) @@ -33830,7 +34208,7 @@ Index * QuikTrim Awk: Other Versions. (line 139) * quit debugger command: Miscellaneous Debugger Commands. (line 99) -* QUIT signal (MS-Windows): Profiling. (line 214) +* QUIT signal (MS-Windows): Profiling. (line 213) * quoting in gawk command lines: Long. (line 26) * quoting in gawk command lines, tricks for: Quoting. (line 91) * quoting, for small awk programs: Comments. (line 27) @@ -33839,12 +34217,12 @@ Index * Rakitzis, Byron: History Sorting. (line 25) * Ramey, Chet <1>: General Data Types. (line 6) * Ramey, Chet: Acknowledgments. (line 60) -* rand: Numeric Functions. (line 33) +* rand: Numeric Functions. (line 48) * random numbers, Cliff: Cliff Random Function. (line 6) * random numbers, rand()/srand() functions: Numeric Functions. - (line 33) -* random numbers, seed of: Numeric Functions. (line 63) + (line 48) +* random numbers, seed of: Numeric Functions. (line 78) * range expressions (regexps): Bracket Expressions. (line 6) * range patterns: Ranges. (line 6) * range patterns, line continuation and: Ranges. (line 65) @@ -33913,7 +34291,7 @@ Index (line 60) * regular expressions, gawk, command-line options: GNU Regexp Operators. (line 70) -* regular expressions, interval expressions and: Options. (line 281) +* regular expressions, interval expressions and: Options. (line 279) * regular expressions, leftmost longest match: Leftmost Longest. (line 6) * regular expressions, operators <1>: Regexp Operators. (line 6) @@ -33930,6 +34308,7 @@ Index * relational operators, See comparison operators: Typing and Comparison. (line 9) * replace in string: String Functions. (line 409) +* retrying input: Retrying Input. (line 6) * return debugger command: Debugger Execution Control. (line 54) * return statement, user-defined functions: Return Statement. (line 6) @@ -33953,7 +34332,7 @@ Index * right shift: Bitwise Functions. (line 53) * right shift, bitwise: Bitwise Functions. (line 32) * Ritchie, Dennis: Basic Data Typing. (line 54) -* RLENGTH variable: Auto-set. (line 252) +* RLENGTH variable: Auto-set. (line 279) * RLENGTH variable, match() function and: String Functions. (line 228) * Robbins, Arnold <1>: Future Extensions. (line 6) * Robbins, Arnold <2>: Bugs. (line 71) @@ -33979,9 +34358,9 @@ Index * RS variable: awk split records. (line 12) * RS variable, multiline records and: Multiple Line. (line 17) * rshift: Bitwise Functions. (line 53) -* RSTART variable: Auto-set. (line 258) +* RSTART variable: Auto-set. (line 285) * RSTART variable, match() function and: String Functions. (line 228) -* RT variable <1>: Auto-set. (line 265) +* RT variable <1>: Auto-set. (line 292) * RT variable <2>: Multiple Line. (line 129) * RT variable: awk split records. (line 125) * Rubin, Paul <1>: Contributors. (line 15) @@ -33994,14 +34373,14 @@ Index (line 68) * sample debugging session: Sample Debugging Session. (line 6) -* sandbox mode: Options. (line 288) +* sandbox mode: Options. (line 286) * save debugger options: Debugger Info. (line 85) * scalar or array: Type Functions. (line 11) * scalar values: Basic Data Typing. (line 13) * scanning arrays: Scanning an Array. (line 6) * scanning multidimensional arrays: Multiscanning. (line 11) * Schorr, Andrew <1>: Contributors. (line 133) -* Schorr, Andrew <2>: Auto-set. (line 297) +* Schorr, Andrew <2>: Auto-set. (line 324) * Schorr, Andrew: Acknowledgments. (line 60) * Schreiber, Bert: Acknowledgments. (line 38) * Schreiber, Rita: Acknowledgments. (line 38) @@ -34020,7 +34399,7 @@ Index * sed utility <1>: Glossary. (line 16) * sed utility <2>: Simple Sed. (line 6) * sed utility: Full Line Fields. (line 22) -* seeding random number generator: Numeric Functions. (line 63) +* seeding random number generator: Numeric Functions. (line 78) * semicolon (;), AWKPATH variable and: PC Using. (line 10) * semicolon (;), separating statements in actions <1>: Statements. (line 10) @@ -34081,14 +34460,14 @@ Index * sidebar, A Constant's Base Does Not Affect Its Value: Nondecimal-numbers. (line 64) * sidebar, Backslash Before Regular Characters: Escape Sequences. - (line 103) + (line 106) * sidebar, Changing FS Does Not Affect the Fields: Full Line Fields. (line 14) -* sidebar, Changing NR and FNR: Auto-set. (line 312) +* sidebar, Changing NR and FNR: Auto-set. (line 339) * sidebar, Controlling Output Buffering with system(): I/O Functions. (line 139) * sidebar, Escape Sequences for Metacharacters: Escape Sequences. - (line 134) + (line 137) * sidebar, FS and IGNORECASE: Field Splitting Summary. (line 38) * sidebar, Interactive Versus Noninteractive Buffering: I/O Functions. @@ -34110,19 +34489,19 @@ Index (line 58) * sidebar, Using close()'s Return Value: Close Files And Pipes. (line 131) -* SIGHUP signal, for dynamic profiling: Profiling. (line 211) -* SIGINT signal (MS-Windows): Profiling. (line 214) -* signals, HUP/SIGHUP, for profiling: Profiling. (line 211) -* signals, INT/SIGINT (MS-Windows): Profiling. (line 214) -* signals, QUIT/SIGQUIT (MS-Windows): Profiling. (line 214) -* signals, USR1/SIGUSR1, for profiling: Profiling. (line 188) +* SIGHUP signal, for dynamic profiling: Profiling. (line 210) +* SIGINT signal (MS-Windows): Profiling. (line 213) +* signals, HUP/SIGHUP, for profiling: Profiling. (line 210) +* signals, INT/SIGINT (MS-Windows): Profiling. (line 213) +* signals, QUIT/SIGQUIT (MS-Windows): Profiling. (line 213) +* signals, USR1/SIGUSR1, for profiling: Profiling. (line 187) * signature program: Signature Program. (line 6) -* SIGQUIT signal (MS-Windows): Profiling. (line 214) -* SIGUSR1 signal, for dynamic profiling: Profiling. (line 188) +* SIGQUIT signal (MS-Windows): Profiling. (line 213) +* SIGUSR1 signal, for dynamic profiling: Profiling. (line 187) * silent debugger command: Debugger Execution Control. (line 10) -* sin: Numeric Functions. (line 74) -* sine: Numeric Functions. (line 74) +* sin: Numeric Functions. (line 89) +* sine: Numeric Functions. (line 89) * single quote ('): One-shot. (line 15) * single quote (') in gawk command lines: Long. (line 35) * single quote ('), in shell commands: Quoting. (line 48) @@ -34172,10 +34551,10 @@ Index * sprintf() function, OFMT variable and: User-modified. (line 113) * sprintf() function, print/printf statements and: Round Function. (line 6) -* sqrt: Numeric Functions. (line 77) +* sqrt: Numeric Functions. (line 92) * square brackets ([]), regexp operator: Regexp Operators. (line 56) -* square root: Numeric Functions. (line 77) -* srand: Numeric Functions. (line 81) +* square root: Numeric Functions. (line 92) +* srand: Numeric Functions. (line 96) * stack frame: Debugging Terms. (line 10) * Stallman, Richard <1>: Glossary. (line 375) * Stallman, Richard <2>: Contributors. (line 23) @@ -34246,9 +34625,9 @@ Index * substr: String Functions. (line 482) * substring: String Functions. (line 482) * Sumner, Andrew: Other Versions. (line 68) -* supplementary groups of gawk process: Auto-set. (line 237) +* supplementary groups of gawk process: Auto-set. (line 260) * switch statement: Switch Statement. (line 6) -* SYMTAB array: Auto-set. (line 269) +* SYMTAB array: Auto-set. (line 296) * syntactic ambiguity: /= operator vs. /=.../ regexp constant: Assignment Ops. (line 148) * system: I/O Functions. (line 107) @@ -34315,7 +34694,7 @@ Index (line 37) * troubleshooting, awk uses FS not IFS: Field Separators. (line 30) * troubleshooting, backslash before nonspecial character: Escape Sequences. - (line 105) + (line 108) * troubleshooting, division: Arithmetic Ops. (line 44) * troubleshooting, fatal errors, field widths, specifying: Constant Size. (line 22) @@ -34371,7 +34750,7 @@ Index * uniq.awk program: Uniq Program. (line 65) * Unix: Glossary. (line 753) * Unix awk, backslashes in escape sequences: Escape Sequences. - (line 117) + (line 120) * Unix awk, close() function and: Close Files And Pipes. (line 133) * Unix awk, password files, field separators and: Command Line Field Separator. @@ -34391,7 +34770,7 @@ Index * user-modifiable variables: User-modified. (line 6) * users, information about, printing: Id Program. (line 6) * users, information about, retrieving: Passwd Functions. (line 16) -* USR1 signal, for dynamic profiling: Profiling. (line 188) +* USR1 signal, for dynamic profiling: Profiling. (line 187) * values, numeric: Basic Data Typing. (line 13) * values, string: Basic Data Typing. (line 13) * variable assignments and input files: Other Arguments. (line 26) @@ -34425,10 +34804,10 @@ Index * variables, uninitialized, as array subscripts: Uninitialized Subscripts. (line 6) * variables, user-defined: Variables. (line 6) -* version of gawk: Auto-set. (line 207) -* version of gawk extension API: Auto-set. (line 232) -* version of GNU MP library: Auto-set. (line 218) -* version of GNU MPFR library: Auto-set. (line 214) +* version of gawk: Auto-set. (line 230) +* version of gawk extension API: Auto-set. (line 255) +* version of GNU MP library: Auto-set. (line 241) +* version of GNU MPFR library: Auto-set. (line 237) * vertical bar (|): Regexp Operators. (line 70) * vertical bar (|), | operator (I/O) <1>: Precedence. (line 65) * vertical bar (|), | operator (I/O): Getline/Pipe. (line 9) @@ -34465,7 +34844,7 @@ Index * whitespace, as field separators: Default Field Splitting. (line 6) * whitespace, functions, calling: Calling Built-in. (line 10) -* whitespace, newlines as: Options. (line 262) +* whitespace, newlines as: Options. (line 260) * Williams, Kent: Contributors. (line 34) * Woehlke, Matthew: Contributors. (line 79) * Woods, John: Contributors. (line 27) @@ -34518,559 +34897,563 @@ Index Tag Table: Node: Top1204 -Node: Foreword342156 -Node: Foreword446600 -Node: Preface48131 -Ref: Preface-Footnote-151002 -Ref: Preface-Footnote-251109 -Ref: Preface-Footnote-351342 -Node: History51484 -Node: Names53835 -Ref: Names-Footnote-154929 -Node: This Manual55075 -Ref: This Manual-Footnote-161575 -Node: Conventions61675 -Node: Manual History64012 -Ref: Manual History-Footnote-167005 -Ref: Manual History-Footnote-267046 -Node: How To Contribute67120 -Node: Acknowledgments68249 -Node: Getting Started73115 -Node: Running gawk75554 -Node: One-shot76744 -Node: Read Terminal78008 -Node: Long80039 -Node: Executable Scripts81552 -Ref: Executable Scripts-Footnote-184341 -Node: Comments84444 -Node: Quoting86926 -Node: DOS Quoting92444 -Node: Sample Data Files93119 -Node: Very Simple95714 -Node: Two Rules100613 -Node: More Complex102499 -Node: Statements/Lines105361 -Ref: Statements/Lines-Footnote-1109816 -Node: Other Features110081 -Node: When111017 -Ref: When-Footnote-1112771 -Node: Intro Summary112836 -Node: Invoking Gawk113720 -Node: Command Line115234 -Node: Options116032 -Ref: Options-Footnote-1131954 -Ref: Options-Footnote-2132183 -Node: Other Arguments132208 -Node: Naming Standard Input135156 -Node: Environment Variables136249 -Node: AWKPATH Variable136807 -Ref: AWKPATH Variable-Footnote-1140104 -Ref: AWKPATH Variable-Footnote-2140149 -Node: AWKLIBPATH Variable140409 -Node: Other Environment Variables141552 -Node: Exit Status145310 -Node: Include Files145986 -Node: Loading Shared Libraries149575 -Node: Obsolete151002 -Node: Undocumented151694 -Node: Invoking Summary151961 -Node: Regexp153624 -Node: Regexp Usage155078 -Node: Escape Sequences157115 -Node: Regexp Operators163125 -Ref: Regexp Operators-Footnote-1170535 -Ref: Regexp Operators-Footnote-2170682 -Node: Bracket Expressions170780 -Ref: table-char-classes172795 -Node: Leftmost Longest175737 -Node: Computed Regexps177039 -Node: GNU Regexp Operators180468 -Node: Case-sensitivity184140 -Ref: Case-sensitivity-Footnote-1187025 -Ref: Case-sensitivity-Footnote-2187260 -Node: Regexp Summary187368 -Node: Reading Files188835 -Node: Records190928 -Node: awk split records191661 -Node: gawk split records196590 -Ref: gawk split records-Footnote-1201129 -Node: Fields201166 -Ref: Fields-Footnote-1203944 -Node: Nonconstant Fields204030 -Ref: Nonconstant Fields-Footnote-1206268 -Node: Changing Fields206471 -Node: Field Separators212402 -Node: Default Field Splitting215106 -Node: Regexp Field Splitting216223 -Node: Single Character Fields219573 -Node: Command Line Field Separator220632 -Node: Full Line Fields223849 -Ref: Full Line Fields-Footnote-1225370 -Ref: Full Line Fields-Footnote-2225416 -Node: Field Splitting Summary225517 -Node: Constant Size227591 -Node: Splitting By Content232170 -Ref: Splitting By Content-Footnote-1236135 -Node: Multiple Line236298 -Ref: Multiple Line-Footnote-1242179 -Node: Getline242358 -Node: Plain Getline244565 -Node: Getline/Variable247205 -Node: Getline/File248354 -Node: Getline/Variable/File249739 -Ref: Getline/Variable/File-Footnote-1251342 -Node: Getline/Pipe251429 -Node: Getline/Variable/Pipe254107 -Node: Getline/Coprocess255238 -Node: Getline/Variable/Coprocess256502 -Node: Getline Notes257241 -Node: Getline Summary260035 -Ref: table-getline-variants260447 -Node: Read Timeout261276 -Ref: Read Timeout-Footnote-1265113 -Node: Command-line directories265171 -Node: Input Summary266076 -Node: Input Exercises269461 -Node: Printing270189 -Node: Print271966 -Node: Print Examples273423 -Node: Output Separators276202 -Node: OFMT278220 -Node: Printf279575 -Node: Basic Printf280360 -Node: Control Letters281932 -Node: Format Modifiers285917 -Node: Printf Examples291923 -Node: Redirection294409 -Node: Special FD301247 -Ref: Special FD-Footnote-1304413 -Node: Special Files304487 -Node: Other Inherited Files305104 -Node: Special Network306104 -Node: Special Caveats306966 -Node: Close Files And Pipes307915 -Ref: Close Files And Pipes-Footnote-1315106 -Ref: Close Files And Pipes-Footnote-2315254 -Node: Output Summary315404 -Node: Output Exercises316402 -Node: Expressions317082 -Node: Values318271 -Node: Constants318948 -Node: Scalar Constants319639 -Ref: Scalar Constants-Footnote-1320501 -Node: Nondecimal-numbers320751 -Node: Regexp Constants323761 -Node: Using Constant Regexps324287 -Node: Variables327450 -Node: Using Variables328107 -Node: Assignment Options330018 -Node: Conversion331893 -Node: Strings And Numbers332417 -Ref: Strings And Numbers-Footnote-1335482 -Node: Locale influences conversions335591 -Ref: table-locale-affects338337 -Node: All Operators338929 -Node: Arithmetic Ops339558 -Node: Concatenation342063 -Ref: Concatenation-Footnote-1344882 -Node: Assignment Ops344989 -Ref: table-assign-ops349968 -Node: Increment Ops351278 -Node: Truth Values and Conditions354709 -Node: Truth Values355792 -Node: Typing and Comparison356841 -Node: Variable Typing357657 -Node: Comparison Operators361324 -Ref: table-relational-ops361734 -Node: POSIX String Comparison365229 -Ref: POSIX String Comparison-Footnote-1366301 -Node: Boolean Ops366440 -Ref: Boolean Ops-Footnote-1370918 -Node: Conditional Exp371009 -Node: Function Calls372747 -Node: Precedence376627 -Node: Locales380287 -Node: Expressions Summary381919 -Node: Patterns and Actions384490 -Node: Pattern Overview385610 -Node: Regexp Patterns387289 -Node: Expression Patterns387832 -Node: Ranges391612 -Node: BEGIN/END394719 -Node: Using BEGIN/END395480 -Ref: Using BEGIN/END-Footnote-1398216 -Node: I/O And BEGIN/END398322 -Node: BEGINFILE/ENDFILE400637 -Node: Empty403543 -Node: Using Shell Variables403860 -Node: Action Overview406133 -Node: Statements408459 -Node: If Statement410307 -Node: While Statement411802 -Node: Do Statement413830 -Node: For Statement414978 -Node: Switch Statement418136 -Node: Break Statement420518 -Node: Continue Statement422611 -Node: Next Statement424438 -Node: Nextfile Statement426819 -Node: Exit Statement429447 -Node: Built-in Variables431858 -Node: User-modified432991 -Ref: User-modified-Footnote-1440625 -Node: Auto-set440687 -Ref: Auto-set-Footnote-1453739 -Ref: Auto-set-Footnote-2453944 -Node: ARGC and ARGV454000 -Node: Pattern Action Summary458218 -Node: Arrays460651 -Node: Array Basics461980 -Node: Array Intro462824 -Ref: figure-array-elements464761 -Ref: Array Intro-Footnote-1467384 -Node: Reference to Elements467512 -Node: Assigning Elements469974 -Node: Array Example470465 -Node: Scanning an Array472224 -Node: Controlling Scanning475247 -Ref: Controlling Scanning-Footnote-1480641 -Node: Numeric Array Subscripts480957 -Node: Uninitialized Subscripts483142 -Node: Delete484759 -Ref: Delete-Footnote-1487508 -Node: Multidimensional487565 -Node: Multiscanning490662 -Node: Arrays of Arrays492251 -Node: Arrays Summary497005 -Node: Functions499096 -Node: Built-in500135 -Node: Calling Built-in501213 -Node: Numeric Functions503208 -Ref: Numeric Functions-Footnote-1507236 -Ref: Numeric Functions-Footnote-2507593 -Ref: Numeric Functions-Footnote-3507641 -Node: String Functions507913 -Ref: String Functions-Footnote-1531414 -Ref: String Functions-Footnote-2531543 -Ref: String Functions-Footnote-3531791 -Node: Gory Details531878 -Ref: table-sub-escapes533659 -Ref: table-sub-proposed535174 -Ref: table-posix-sub536536 -Ref: table-gensub-escapes538073 -Ref: Gory Details-Footnote-1538906 -Node: I/O Functions539057 -Ref: I/O Functions-Footnote-1546293 -Node: Time Functions546440 -Ref: Time Functions-Footnote-1556949 -Ref: Time Functions-Footnote-2557017 -Ref: Time Functions-Footnote-3557175 -Ref: Time Functions-Footnote-4557286 -Ref: Time Functions-Footnote-5557398 -Ref: Time Functions-Footnote-6557625 -Node: Bitwise Functions557891 -Ref: table-bitwise-ops558453 -Ref: Bitwise Functions-Footnote-1562781 -Node: Type Functions562953 -Node: I18N Functions564105 -Node: User-defined565752 -Node: Definition Syntax566557 -Ref: Definition Syntax-Footnote-1572216 -Node: Function Example572287 -Ref: Function Example-Footnote-1575208 -Node: Function Caveats575230 -Node: Calling A Function575748 -Node: Variable Scope576706 -Node: Pass By Value/Reference579699 -Node: Return Statement583196 -Node: Dynamic Typing586175 -Node: Indirect Calls587104 -Ref: Indirect Calls-Footnote-1597347 -Node: Functions Summary597475 -Node: Library Functions600177 -Ref: Library Functions-Footnote-1603785 -Ref: Library Functions-Footnote-2603928 -Node: Library Names604099 -Ref: Library Names-Footnote-1607557 -Ref: Library Names-Footnote-2607780 -Node: General Functions607866 -Node: Strtonum Function608969 -Node: Assert Function611991 -Node: Round Function615315 -Node: Cliff Random Function616856 -Node: Ordinal Functions617872 -Ref: Ordinal Functions-Footnote-1620935 -Ref: Ordinal Functions-Footnote-2621187 -Node: Join Function621398 -Ref: Join Function-Footnote-1623168 -Node: Getlocaltime Function623368 -Node: Readfile Function627112 -Node: Shell Quoting629084 -Node: Data File 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Values971578 +Ref: table-value-types-returned972305 +Node: Accessing Parameters973262 +Node: Symbol Table Access974496 +Node: Symbol table by name975010 +Node: Symbol table by cookie977030 +Ref: Symbol table by cookie-Footnote-1981175 +Node: Cached values981238 +Ref: Cached values-Footnote-1984734 +Node: Array Manipulation984825 +Ref: Array Manipulation-Footnote-1985915 +Node: Array Data Types985952 +Ref: Array Data Types-Footnote-1988607 +Node: Array Functions988699 +Node: Flattening Arrays992558 +Node: Creating Arrays999460 +Node: Redirection API1004231 +Node: Extension API Variables1007056 +Node: Extension Versioning1007689 +Node: Extension API Informational Variables1009580 +Node: Extension API Boilerplate1010645 +Node: Finding Extensions1014454 +Node: Extension Example1015014 +Node: Internal File Description1015786 +Node: Internal File Ops1019853 +Ref: Internal File Ops-Footnote-11031604 +Node: Using Internal File Ops1031744 +Ref: Using Internal File Ops-Footnote-11034127 +Node: Extension Samples1034400 +Node: Extension Sample File Functions1035928 +Node: Extension Sample Fnmatch1043609 +Node: Extension Sample Fork1045097 +Node: Extension Sample Inplace1046312 +Node: Extension Sample Ord1048398 +Node: Extension Sample Readdir1049234 +Ref: table-readdir-file-types1050111 +Node: Extension Sample Revout1050922 +Node: Extension Sample Rev2way1051511 +Node: Extension Sample Read write array1052251 +Node: Extension Sample Readfile1054191 +Node: Extension Sample Time1055286 +Node: Extension Sample API Tests1056634 +Node: gawkextlib1057125 +Node: Extension summary1059572 +Node: Extension Exercises1063261 +Node: Language History1064757 +Node: V7/SVR3.11066413 +Node: SVR41068566 +Node: POSIX1070000 +Node: BTL1071381 +Node: POSIX/GNU1072112 +Node: Feature History1077951 +Node: Common Extensions1091941 +Node: Ranges and Locales1093313 +Ref: Ranges and Locales-Footnote-11097932 +Ref: Ranges and Locales-Footnote-21097959 +Ref: Ranges and Locales-Footnote-31098194 +Node: Contributors1098415 +Node: History summary1103955 +Node: Installation1105334 +Node: Gawk Distribution1106280 +Node: Getting1106764 +Node: Extracting1107587 +Node: Distribution contents1109224 +Node: Unix Installation1115326 +Node: Quick Installation1116009 +Node: Shell Startup Files1118420 +Node: Additional Configuration Options1119499 +Node: Configuration Philosophy1121303 +Node: Non-Unix Installation1123672 +Node: PC Installation1124130 +Node: PC Binary Installation1125450 +Node: PC Compiling1127298 +Ref: PC Compiling-Footnote-11130319 +Node: PC Testing1130428 +Node: PC Using1131604 +Node: Cygwin1135719 +Node: MSYS1136489 +Node: VMS Installation1136990 +Node: VMS Compilation1137782 +Ref: VMS Compilation-Footnote-11139011 +Node: VMS Dynamic Extensions1139069 +Node: VMS Installation Details1140753 +Node: VMS Running1143004 +Node: VMS GNV1145844 +Node: VMS Old Gawk1146579 +Node: Bugs1147049 +Node: Other Versions1150938 +Node: Installation summary1157372 +Node: Notes1158431 +Node: Compatibility Mode1159296 +Node: Additions1160078 +Node: Accessing The Source1161003 +Node: Adding Code1162438 +Node: New Ports1168595 +Node: Derived Files1173077 +Ref: Derived Files-Footnote-11178552 +Ref: Derived Files-Footnote-21178586 +Ref: Derived Files-Footnote-31179182 +Node: Future Extensions1179296 +Node: Implementation Limitations1179902 +Node: Extension Design1181150 +Node: Old Extension Problems1182304 +Ref: Old Extension Problems-Footnote-11183821 +Node: Extension New Mechanism Goals1183878 +Ref: Extension New Mechanism Goals-Footnote-11187238 +Node: Extension Other Design Decisions1187427 +Node: Extension Future Growth1189535 +Node: Old Extension Mechanism1190371 +Node: Notes summary1192133 +Node: Basic Concepts1193319 +Node: Basic High Level1194000 +Ref: figure-general-flow1194272 +Ref: figure-process-flow1194871 +Ref: Basic High Level-Footnote-11198100 +Node: Basic Data Typing1198285 +Node: Glossary1201613 +Node: Copying1233542 +Node: GNU Free Documentation License1271098 +Node: Index1296234 End Tag Table diff --git a/doc/gawk.texi b/doc/gawk.texi index f1cef1c9..501aacde 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -604,6 +604,7 @@ particular records in a file and perform operations upon them. @code{getline}. * Getline Summary:: Summary of @code{getline} Variants. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -633,6 +634,7 @@ particular records in a file and perform operations upon them. * Special Caveats:: Things to watch out for. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. * Values:: Constants, Variables, and Regular @@ -944,6 +946,7 @@ particular records in a file and perform operations upon them. * Array Functions:: Functions for working with arrays. * Flattening Arrays:: How to flatten arrays. * Creating Arrays:: How to create and populate arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension Versioning:: API Version information. * Extension API Informational Variables:: Variables providing information about @@ -1002,6 +1005,7 @@ particular records in a file and perform operations upon them. * Unix Installation:: Installing @command{gawk} under various versions of Unix. * Quick Installation:: Compiling @command{gawk} under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. * Non-Unix Installation:: Installation on Other Operating @@ -4082,10 +4086,8 @@ No space is allowed between the @option{-o} and @var{file}, if @var{file} is supplied. @quotation NOTE -Due to the way @command{gawk} has evolved, with this option -your program still executes. This will change in the -next major release, such that @command{gawk} will only -pretty-print the program and not run it. +In the past, this option would also execute your program. +This is no longer the case. @end quotation @item @option{-O} @@ -4486,6 +4488,9 @@ searches first in the current directory and then in @file{/usr/local/share/awk}. In practice, this means that you will rarely need to change the value of @env{AWKPATH}. +@xref{Shell Startup Files}, for information on functions that help to +manipulate the @env{AWKPATH} variable. + @command{gawk} places the value of the search path that it used into @code{ENVIRON["AWKPATH"]}. This provides access to the actual search path value from within an @command{awk} program. @@ -4517,6 +4522,9 @@ an empty value, @command{gawk} uses a default path; this is typically @samp{/usr/local/lib/gawk}, although it can vary depending upon how @command{gawk} was built. +@xref{Shell Startup Files}, for information on functions that help to +manipulate the @env{AWKLIBPATH} variable. + @command{gawk} places the value of the search path that it used into @code{ENVIRON["AWKLIBPATH"]}. This provides access to the actual search path value from within an @command{awk} program. @@ -4544,6 +4552,8 @@ wait for input before returning with an error. Controls the number of times @command{gawk} attempts to retry a two-way TCP/IP (socket) connection before giving up. @xref{TCP/IP Networking}. +Note that when nonfatal I/O is enabled (@pxref{Nonfatal}), +@command{gawk} only tries to open a TCP/IP socket once. @item POSIXLY_CORRECT Causes @command{gawk} to switch to POSIX-compatibility @@ -4593,14 +4603,6 @@ two regexp matchers that @command{gawk} uses internally. (There aren't supposed to be differences, but occasionally theory and practice don't coordinate with each other.) -@item GAWK_NO_PP_RUN -When @command{gawk} is invoked with the @option{--pretty-print} option, -it will not run the program if this environment variable exists. - -@quotation CAUTION -This variable will not survive into the next major release. -@end quotation - @item GAWK_STACKSIZE This specifies the amount by which @command{gawk} should grow its internal evaluation stack, when needed. @@ -4898,6 +4900,13 @@ Similarly, you may use @code{print} or @code{printf} statements in the @var{init} and @var{increment} parts of a @code{for} loop. This is another long-undocumented ``feature'' of Unix @command{awk}. +@command{gawk} lets you use the names of built-in functions that are +@command{gawk} extensions as the names of parameters in user-defined functions. +This is intended to ``future-proof'' old code that happens to use +function names added by @command{gawk} after the code was written. +Standard @command{awk} built-in functions, such as @code{sin()} or +@code{substr()} are @emph{not} shadowed in this way. + @end ignore @node Invoking Summary @@ -5180,17 +5189,21 @@ between @samp{0} and @samp{7}. For example, the code for the ASCII ESC @item \x@var{hh}@dots{} The hexadecimal value @var{hh}, where @var{hh} stands for a sequence of hexadecimal digits (@samp{0}--@samp{9}, and either @samp{A}--@samp{F} -or @samp{a}--@samp{f}). Like the same construct -in ISO C, the escape sequence continues until the first nonhexadecimal -digit is seen. @value{COMMONEXT} -However, using more than two hexadecimal digits produces -undefined results. (The @samp{\x} escape sequence is not allowed in -POSIX @command{awk}.) +or @samp{a}--@samp{f}). A maximum of two digts are allowed after +the @samp{\x}. Any further hexadecimal digits are treated as simple +letters or numbers. @value{COMMONEXT} +(The @samp{\x} escape sequence is not allowed in POSIX awk.) @quotation CAUTION -The next major release of @command{gawk} will change, such -that a maximum of two hexadecimal digits following the -@samp{\x} will be used. +In ISO C, the escape sequence continues until the first nonhexadecimal +digit is seen. +For many years, @command{gawk} would continue incorporating +hexadecimal digits into the value until a non-hexadecimal digit +or the end of the string was encountered. +However, using more than two hexadecimal digits produced +undefined results. +As of @value{PVERSION} 4.2, only two digits +are processed. @end quotation @cindex @code{\} (backslash), @code{\/} escape sequence @@ -6323,6 +6336,7 @@ used with it do not have to be named on the @command{awk} command line * Getline:: Reading files under explicit program control using the @code{getline} function. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -8114,6 +8128,13 @@ a record, such as a file that cannot be opened, then @code{getline} returns @minus{}1. In this case, @command{gawk} sets the variable @code{ERRNO} to a string describing the error that occurred. +If @code{ERRNO} indicates that the I/O operation may be +retried, and @code{PROCINFO["@var{input}", "RETRY"]} is set, +then @code{getline} returns @minus{}2 +instead of @minus{}1, and further calls to @code{getline} +may be attemped. @DBXREF{Retrying Input} for further information about +this feature. + In the following examples, @var{command} stands for a string value that represents a shell command. @@ -8768,7 +8789,8 @@ on a per-command or per-connection basis. the attempt to read from the underlying device may succeed in a later attempt. This is a limitation, and it also means that you cannot use this to multiplex input from -two or more sources. +two or more sources. @DBXREF{Retrying Input} for a way to enable +later I/O attempts to succeed. Assigning a timeout value prevents read operations from blocking indefinitely. But bear in mind that there are other ways @@ -8778,6 +8800,36 @@ a connection before it can start reading any data, or the attempt to open a FIFO special file for reading can block indefinitely until some other process opens it for writing. +@node Retrying Input +@section Retrying Reads After Certain Input Errors +@cindex retrying input + +@cindex differences in @command{awk} and @command{gawk}, retrying input +This @value{SECTION} describes a feature that is specific to @command{gawk}. + +When @command{gawk} encounters an error while reading input, by +default @code{getline} returns @minus{}1, and subsequent attempts to +read from that file result in an end-of-file indication. However, you +may optionally instruct @command{gawk} to allow I/O to be retried when +certain errors are encountered by setting a special element in +the @code{PROCINFO} array (@pxref{Auto-set}): + +@example +PROCINFO["@var{input_name}", "RETRY"] = 1 +@end example + +When this element exists, @command{gawk} checks the value of the system +(C language) +@code{errno} variable when an I/O error occurs. If @code{errno} indicates +a subsequent I/O attempt may succeed, @code{getline} instead returns +@minus{}2 and +further calls to @code{getline} may succeed. This applies to the @code{errno} +values @code{EAGAIN}, @code{EWOULDBLOCK}, @code{EINTR}, or @code{ETIMEDOUT}. + +This feature is useful in conjunction with +@code{PROCINFO["@var{input_name}", "READ_TIMEOUT"]} or situations where a file +descriptor has been configured to behave in a non-blocking fashion. + @node Command-line directories @section Directories on the Command Line @cindex differences in @command{awk} and @command{gawk}, command-line directories @@ -8939,6 +8991,7 @@ and discusses the @code{close()} built-in function. @command{gawk} allows access to inherited file descriptors. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. @end menu @@ -10445,6 +10498,71 @@ when closing a pipe. @end ifnotdocbook +@node Nonfatal +@section Enabling Nonfatal Output + +This @value{SECTION} describes a @command{gawk}-specific feature. + +In standard @command{awk}, output with @code{print} or @code{printf} +to a nonexistent file, or some other I/O error (such as filling up the +disk) is a fatal error. + +@example +$ @kbd{gawk 'BEGIN @{ print "hi" > "/no/such/file" @}'} +@error{} gawk: cmd. line:1: fatal: can't redirect to `/no/such/file' (No such file or directory) +@end example + +@command{gawk} makes it possible to detect that an error has +occurred, allowing you to possibly recover from the error, or +at least print an error message of your choosing before exiting. +You can do this in one of two ways: + +@itemize @bullet +@item +For all output files, by assigning any value to @code{PROCINFO["NONFATAL"]}. + +@item +On a per-file basis, by assigning any value to +@code{PROCINFO[@var{filename}, "NONFATAL"]}. +Here, @var{filename} is the name of the file to which +you wish output to be nonfatal. +@end itemize + +Once you have enabled nonfatal output, you must check @code{ERRNO} +after every relevant @code{print} or @code{printf} statement to +see if something went wrong. It is also a good idea to initialize +@code{ERRNO} to zero before attempting the output. For example: + +@example +$ @kbd{gawk '} +> @kbd{BEGIN @{} +> @kbd{ PROCINFO["NONFATAL"] = 1} +> @kbd{ ERRNO = 0} +> @kbd{ print "hi" > "/no/such/file"} +> @kbd{ if (ERRNO) @{} +> @kbd{ print("Output failed:", ERRNO) > "/dev/stderr"} +> @kbd{ exit 1} +> @kbd{ @}} +> @kbd{@}'} +@error{} Output failed: No such file or directory +@end example + +Here, @command{gawk} did not produce a fatal error; instead +it let the @command{awk} program code detect the problem and handle it. + +This mechanism works also for standard output and standard error. +For standard output, you may use @code{PROCINFO["-", "NONFATAL"]} +or @code{PROCINFO["/dev/stdout", "NONFATAL"]}. For standard error, use +@code{PROCINFO["/dev/stderr", "NONFATAL"]}. + +When attempting to open a TCP/IP socket (@pxref{TCP/IP Networking}), +@command{gawk} tries multiple times. The @env{GAWK_SOCK_RETRIES} +environment variable (@pxref{Other Environment Variables}) allows you to +override @command{gawk}'s builtin default number of attempts. However, +once nonfatal I/O is enabled for a given socket, @command{gawk} only +retries once, relying on @command{awk}-level code to notice that there +was a problem. + @node Output Summary @section Summary @@ -10473,6 +10591,12 @@ Use @code{close()} to close open file, pipe, and coprocess redirections. For coprocesses, it is possible to close only one direction of the communications. +@item +Normally errors with @code{print} or @code{printf} are fatal. +@command{gawk} lets you make output errors be nonfatal either for +all files or on a per-file basis. You must then check for errors +after every relevant output statement. + @end itemize @c EXCLUDE START @@ -14806,10 +14930,24 @@ opens the next file. An associative array containing the values of the environment. The array indices are the environment variable names; the elements are the values of the particular environment variables. For example, -@code{ENVIRON["HOME"]} might be @code{"/home/arnold"}. Changing this array -does not affect the environment passed on to any programs that -@command{awk} may spawn via redirection or the @code{system()} function. -(In a future version of @command{gawk}, it may do so.) +@code{ENVIRON["HOME"]} might be @code{/home/arnold}. + +For POSIX @command{awk}, changing this array does not affect the +environment passed on to any programs that @command{awk} may spawn via +redirection or the @code{system()} function. + +However, beginning with version 4.2, if not in POSIX +compatibility mode, @command{gawk} does update its own environment when +@code{ENVIRON} is changed, thus changing the environment seen by programs +that it creates. You should therefore be especially careful if you +modify @code{ENVIRON["PATH"]}, which is the search path for finding +executable programs. + +This can also affect the running @command{gawk} program, since some of the +built-in functions may pay attention to certain environment variables. +The most notable instance of this is @code{mktime()} (@pxref{Time +Functions}), which pays attention the value of the @env{TZ} environment +variable on many systems. Some operating systems may not have environment variables. On such systems, the @code{ENVIRON} array is empty (except for @@ -14843,6 +14981,11 @@ value to be meaningful when an I/O operation returns a failure value, such as @code{getline} returning @minus{}1. You are, of course, free to clear it yourself before doing an I/O operation. +If the value of @code{ERRNO} corresponds to a system error in the C +@code{errno} variable, then @code{PROCINFO["errno"]} will be set to the value +of @code{errno}. For non-system errors, @code{PROCINFO["errno"]} will +be zero. + @cindex @code{FILENAME} variable @cindex dark corner, @code{FILENAME} variable @item @code{FILENAME} @@ -14911,6 +15054,10 @@ are guaranteed to be available: @item PROCINFO["egid"] The value of the @code{getegid()} system call. +@item PROCINFO["errno"] +The value of the C @code{errno} variable when @code{ERRNO} is set to +the associated error message. + @item PROCINFO["euid"] @cindex effective user ID of @command{gawk} user The value of the @code{geteuid()} system call. @@ -15050,6 +15197,11 @@ open input file, pipe, or coprocess. @DBXREF{Read Timeout} for more information. @item +It may be used to indicate that input may be retried when it fails due to +certain errors. +@DBXREF{Retrying Input} for more information. + +@item It may be used to cause coprocesses to communicate over pseudo-ttys instead of through two-way pipes; this is discussed further in @ref{Two-way I/O}. @@ -16964,6 +17116,23 @@ truncated toward zero. For example, @code{int(3)} is 3, @code{int(3.9)} is 3, @code{int(-3.9)} is @minus{}3, and @code{int(-3)} is @minus{}3 as well. +@item @code{intdiv(@var{numerator}, @var{denominator}, @var{result})} +@cindexawkfunc{intdiv} +@cindex intdiv +Perform integer division, similar to the standard C function of the +same name. First, truncate @code{numerator} and @code{denominator} +towards zero, creating integer values. Clear the @code{result} +array, and then set @code{result["quotient"]} to the result of +@samp{numerator / denominator}, truncated towards zero to an integer, +and set @code{result["remainder"]} to the result of @samp{numerator % +denominator}, truncated towards zero to an integer. This function is +primarily intended for use with arbitrary length integers; it avoids +creating MPFR arbitrary precision floating-point values (@pxref{Arbitrary +Precision Integers}). + +This function is a @code{gawk} extension. It is not available in +compatibility mode (@pxref{Options}). + @item @code{log(@var{x})} @cindexawkfunc{log} @cindex logarithm @@ -27765,8 +27934,7 @@ The profiled version of your program may not look exactly like what you typed when you wrote it. This is because @command{gawk} creates the profiled version by ``pretty-printing'' its internal representation of the program. The advantage to this is that @command{gawk} can produce -a standard representation. The disadvantage is that all source code -comments are lost. +a standard representation. Also, things such as: @example @@ -27860,10 +28028,26 @@ When called this way, @command{gawk} ``pretty-prints'' the program into @file{awkprof.out}, without any execution counts. @quotation NOTE -The @option{--pretty-print} option still runs your program. -This will change in the next major release. +Once upon a time, the @option{--pretty-print} option would also run +your program. This is is no longer the case. @end quotation +There is a significant difference between the output created when +profiling, and that created when pretty-printing. Pretty-printed output +preserves the original comments that were in the program, although their +placement may not correspond exactly to their original locations in the +source code. + +However, as a deliberate design decision, profiling output @emph{omits} +the original program's comments. This allows you to focus on the +execution count data and helps you avoid the temptation to use the +profiler for pretty-printing. + +Additionally, pretty-printed output does not have the leading indentation +that the profiling output does. This makes it easy to pretty-print your +code once development is completed, and then use the result as the final +version of your program. + @node Advanced Features Summary @section Summary @@ -30937,6 +31121,122 @@ to just use the following: gawk -M 'BEGIN @{ n = 13; print n % 2 @}' @end example +When dividing two arbitrary precision integers with either +@samp{/} or @samp{%}, the result is typically an arbitrary +precision floating point value (unless the denominator evenly +divides into the numerator). In order to do integer division +or remainder with arbitrary precision integers, use the built-in +@code{intdiv()} function (@pxref{Numeric Functions}). + +You can simulate the @code{intdiv()} function in standard @command{awk} +using this user-defined function: + +@example +@c file eg/lib/intdiv.awk +# intdiv --- do integer division + +@c endfile +@ignore +@c file eg/lib/intdiv.awk +# +# Arnold Robbins, arnold@@skeeve.com, Public Domain +# July, 2014 +# +# Name changed from div() to intdiv() +# April, 2015 + +@c endfile + +@end ignore +@c file eg/lib/intdiv.awk +function intdiv(numerator, denominator, result) +@{ + split("", result) + + numerator = int(numerator) + denominator = int(denominator) + result["quotient"] = int(numerator / denominator) + result["remainder"] = int(numerator % denominator) + + return 0.0 +@} +@c endfile +@end example + +The following example program, contributed by Katie Wasserman, +uses @code{intdiv()} to +compute the digits of @value{PI} to as many places as you +choose to set: + +@example +@c file eg/prog/pi.awk +# pi.awk --- compute the digits of pi +@c endfile +@c endfile +@ignore +@c file eg/prog/pi.awk +# +# Katie Wasserman, katie@@wass.net +# August 2014 +@c endfile +@end ignore +@c file eg/prog/pi.awk + +BEGIN @{ + digits = 100000 + two = 2 * 10 ^ digits + pi = two + for (m = digits * 4; m > 0; --m) @{ + d = m * 2 + 1 + x = pi * m + intdiv(x, d, result) + pi = result["quotient"] + pi = pi + two + @} + print pi +@} +@c endfile +@end example + +@ignore +Date: Wed, 20 Aug 2014 10:19:11 -0400 +To: arnold@skeeve.com +From: Katherine Wasserman <katie@wass.net> +Subject: Re: computation of digits of pi? + +Arnold, + +>The program that you sent to compute the digits of pi using div(). Is +>that some standard algorithm that every math student knows? If so, +>what's it called? + +It's not that well known but it's not that obscure either + +It's Euler's modification to Newton's method for calculating pi. + +Take a look at lines (23) - (25) here: http://mathworld.wolfram.com/PiFormulas.htm + +The algorithm I wrote simply expands the multiply by 2 and works from the innermost expression outwards. I used this to program HP calculators because it's quite easy to modify for tiny memory devices with smallish word sizes. + +http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=899 + +-Katie +@end ignore + +When asked about the algorithm used, Katie replied: + +@quotation +It's not that well known but it's not that obscure either. +It's Euler's modification to Newton's method for calculating pi. +Take a look at lines (23) - (25) here: @uref{http://mathworld.wolfram.com/PiFormulas.html}. + +The algorithm I wrote simply expands the multiply by 2 and works from +the innermost expression outwards. I used this to program HP calculators +because it's quite easy to modify for tiny memory devices with smallish +word sizes. See +@uref{http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=899}. +@end quotation + @node POSIX Floating Point Problems @section Standards Versus Existing Practice @@ -31354,6 +31654,7 @@ This (rather large) @value{SECTION} describes the API in detail. * Symbol Table Access:: Functions for accessing global variables. * Array Manipulation:: Functions for working with arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension API Boilerplate:: Boilerplate code for using the API. @end menu @@ -31429,6 +31730,10 @@ Clearing an array @item Flattening an array for easy C-style looping over all its indices and elements @end itemize + +@item +Accessing and manipulating redirections. + @end itemize Some points about using the API: @@ -33399,6 +33704,75 @@ $ @kbd{AWKLIBPATH=$PWD ./gawk -f subarray.awk} (@DBXREF{Finding Extensions} for more information on the @env{AWKLIBPATH} environment variable.) +@node Redirection API +@subsection Accessing and Manipulating Redirections + +The following function allows extensions to access and manipulate redirections. + +@table @code +@item awk_bool_t get_file(const char *name, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ size_t name_len, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const char *filetype, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ int fd, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const awk_input_buf_t **ibufp, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const awk_output_buf_t **obufp); +Look up a file in @command{gawk}'s internal redirection table. +If @code{name} is @code{NULL} or @code{name_len} is zero, return +data for the currently open input file corresponding to @code{FILENAME}. +(This does not access the @code{filetype} argument, so that may be undefined). +If the file is not already open, attempt to open it. +The @code{filetype} argument must be zero-terminated and should be one of: + +@table @code +@item ">" +A file opened for output. + +@item ">>" +A file opened for append. + +@item "<" +A file opened for input. + +@item "|>" +A pipe opened for output. + +@item "|<" +A pipe opened for input. + +@item "|&" +A two-way coprocess. +@end table + +On error, return a @code{false} value. Otherwise, return +@code{true}, and return additional information about the redirection +in the @code{ibufp} and @code{obufp} pointers. For input +redirections, the @code{*ibufp} value should be non-@code{NULL}, +and @code{*obufp} should be @code{NULL}. For output redirections, +the @code{*obufp} value should be non-@code{NULL}, and @code{*ibufp} +should be @code{NULL}. For two-way coprocesses, both values should +be non-@code{NULL}. + +In the usual case, the extension is interested in @code{(*ibufp)->fd} +and/or @code{fileno((*obufp)->fp)}. If the file is not already +open, and the @code{fd} argument is non-negative, @command{gawk} +will use that file descriptor instead of opening the file in the +usual way. If @code{fd} is non-negative, but the file exists already, +@command{gawk} ignores @code{fd} and returns the existing file. It is +the caller's responsibility to notice that neither the @code{fd} in +the returned @code{awk_input_buf_t} nor the @code{fd} in the returned +@code{awk_output_buf_t} matches the requested value. + +Note that supplying a file descriptor is currently @emph{not} supported +for pipes. However, supplying a file descriptor should work for input, +output, append, and two-way (coprocess) sockets. If @code{filetype} +is two-way, @command{gawk} assumes that it is a socket! Note that in +the two-way case, the input and output file descriptors may differ. +To check for success, you must check whether either matches. +@end table + +It is anticipated that this API function will be used to implement I/O +multiplexing and a socket library. + @node Extension API Variables @subsection API Variables @@ -34940,18 +35314,21 @@ As of this writing, there are seven extensions: GD graphics library extension @item +MPFR library extension +(this provides access to a number of MPFR functions that @command{gawk}'s +native MPFR support does not) + +@item PDF extension @item PostgreSQL extension @item -MPFR library extension -(this provides access to a number of MPFR functions that @command{gawk}'s -native MPFR support does not) +Redis extension @item -Redis extension +Select extension @item XML parser extension, using the @uref{http://expat.sourceforge.net, Expat} @@ -35580,6 +35957,10 @@ Indirect function calls @item Directories on the command line produce a warning and are skipped (@pxref{Command-line directories}) + +@item +Output with @code{print} and @code{printf} need not be fatal +(@pxref{Nonfatal}) @end itemize @item @@ -35667,6 +36048,11 @@ The @code{isarray()} function to check if a variable is an array or not The @code{bindtextdomain()}, @code{dcgettext()}, and @code{dcngettext()} functions for internationalization (@pxref{Programmer i18n}) + +@item +The @code{intdiv()} function for doing integer +division and remainder +(@pxref{Numeric Functions}) @end itemize @item @@ -35799,6 +36185,16 @@ for @command{gawk} @value{PVERSION} 4.1: Ultrix @end itemize +@item +Support for the following systems was removed from the code +for @command{gawk} @value{PVERSION} 4.2: + +@c nested table +@itemize @value{MINUS} +@item +MirBSD +@end itemize + @end itemize @c XXX ADD MORE STUFF HERE @@ -36420,6 +36816,44 @@ Redirected @code{getline} became allowed inside The @code{where} command was added to the debugger (@pxref{Execution Stack}). +@item +Support for Ultrix was removed. + +@end itemize + +Version 4.2 introduced the following changes: + +@itemize @bullet +@item +Changes to @code{ENVIRON} are reflected into @command{gawk}'s +environment and that of programs that it runs. +@xref{Auto-set}. + +@item +The @option{--pretty-print} option no longer runs the @command{awk} +program too. +@xref{Options}. + +@item +The @command{igawk} program and its manual page are no longer +installed when @command{gawk} is built. +@xref{Igawk Program}. + +@item +The @code{intdiv()} function. +@xref{Numeric Functions}. + +@item +The maximum number of hexdecimal digits in @samp{\x} escapes +is now two. +@xref{Escape Sequences}. + +@item +Nonfatal output with @code{print} and @code{printf}. +@xref{Nonfatal}. + +@item +Support for MirBSD was removed. @end itemize @c XXX ADD MORE STUFF HERE @@ -37086,6 +37520,8 @@ The generated Info file for The @command{troff} source for a manual page describing the @command{igawk} program presented in @ref{Igawk Program}. +(Since @command{gawk} can do its own @code{@@include} processing, +neither @command{igawk} nor @file{igawk.1} are installed.) @item doc/Makefile.in The input file used during the configuration process to generate the @@ -37130,8 +37566,6 @@ source file for this @value{DOCUMENT}. It also contains a @file{Makefile.in} fil @file{Makefile.am} is used by GNU Automake to create @file{Makefile.in}. The library functions from @ref{Library Functions}, -and the @command{igawk} program from -@DBREF{Igawk Program} are included as ready-to-use files in the @command{gawk} distribution. They are installed as part of the installation process. The rest of the programs in this @value{DOCUMENT} are available in appropriate @@ -37142,6 +37576,12 @@ The source code, manual pages, and infrastructure files for the sample extensions included with @command{gawk}. @xref{Dynamic Extensions}, for more information. +@item extras/* +Additional non-essential files. Currently, this directory contains some shell +startup files to be installed in @file{/etc/profile.d} to aid in manipulating +the @env{AWKPATH} and @env{AWKLIBPATH} environment variables. +@xref{Shell Startup Files}, for more information. + @item posix/* Files needed for building @command{gawk} on POSIX-compliant systems. @@ -37173,6 +37613,7 @@ to configure @command{gawk} for your system yourself. @menu * Quick Installation:: Compiling @command{gawk} under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. @end menu @@ -37253,6 +37694,44 @@ is likely that you will be asked for your password, and you will have to have been set up previously as a user who is allowed to run the @command{sudo} command. +@node Shell Startup Files +@appendixsubsec Shell Startup Files + +The distribution contains shell startup files @file{gawk.sh} and +@file{gawk.csh} containing functions to aid in manipulating +the @env{AWKPATH} and @env{AWKLIBPATH} environment variables. +On a Fedora system, these files should be installed in @file{/etc/profile.d}; +on other platforms, the appropriate location may be different. + +@table @command + +@cindex @command{gawkpath_default} shell function +@item gawkpath_default +Reset the @env{AWKPATH} environment variable to its default value. + +@cindex @command{gawkpath_prepend} shell function +@item gawkpath_prepend +Add the argument to the front of the @env{AWKPATH} environment variable. + +@cindex @command{gawkpath_append} shell function +@item gawkpath_append +Add the argument to the end of the @env{AWKPATH} environment variable. + +@cindex @command{gawklibpath_default} shell function +@item gawklibpath_default +Reset the @env{AWKLIBPATH} environment variable to its default value. + +@cindex @command{gawklibpath_prepend} shell function +@item gawklibpath_prepend +Add the argument to the front of the @env{AWKLIBPATH} environment variable. + +@cindex @command{gawklibpath_append} shell function +@item gawklibpath_append +Add the argument to the end of the @env{AWKLIBPATH} environment variable. + +@end table + + @node Additional Configuration Options @appendixsubsec Additional Configuration Options @cindex @command{gawk}, configuring, options diff --git a/doc/gawktexi.in b/doc/gawktexi.in index af21c5a2..663353d4 100644 --- a/doc/gawktexi.in +++ b/doc/gawktexi.in @@ -599,6 +599,7 @@ particular records in a file and perform operations upon them. @code{getline}. * Getline Summary:: Summary of @code{getline} Variants. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -628,6 +629,7 @@ particular records in a file and perform operations upon them. * Special Caveats:: Things to watch out for. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. * Values:: Constants, Variables, and Regular @@ -939,6 +941,7 @@ particular records in a file and perform operations upon them. * Array Functions:: Functions for working with arrays. * Flattening Arrays:: How to flatten arrays. * Creating Arrays:: How to create and populate arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension Versioning:: API Version information. * Extension API Informational Variables:: Variables providing information about @@ -997,6 +1000,7 @@ particular records in a file and perform operations upon them. * Unix Installation:: Installing @command{gawk} under various versions of Unix. * Quick Installation:: Compiling @command{gawk} under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. * Non-Unix Installation:: Installation on Other Operating @@ -3993,10 +3997,8 @@ No space is allowed between the @option{-o} and @var{file}, if @var{file} is supplied. @quotation NOTE -Due to the way @command{gawk} has evolved, with this option -your program still executes. This will change in the -next major release, such that @command{gawk} will only -pretty-print the program and not run it. +In the past, this option would also execute your program. +This is no longer the case. @end quotation @item @option{-O} @@ -4397,6 +4399,9 @@ searches first in the current directory and then in @file{/usr/local/share/awk}. In practice, this means that you will rarely need to change the value of @env{AWKPATH}. +@xref{Shell Startup Files}, for information on functions that help to +manipulate the @env{AWKPATH} variable. + @command{gawk} places the value of the search path that it used into @code{ENVIRON["AWKPATH"]}. This provides access to the actual search path value from within an @command{awk} program. @@ -4428,6 +4433,9 @@ an empty value, @command{gawk} uses a default path; this is typically @samp{/usr/local/lib/gawk}, although it can vary depending upon how @command{gawk} was built. +@xref{Shell Startup Files}, for information on functions that help to +manipulate the @env{AWKLIBPATH} variable. + @command{gawk} places the value of the search path that it used into @code{ENVIRON["AWKLIBPATH"]}. This provides access to the actual search path value from within an @command{awk} program. @@ -4455,6 +4463,8 @@ wait for input before returning with an error. Controls the number of times @command{gawk} attempts to retry a two-way TCP/IP (socket) connection before giving up. @xref{TCP/IP Networking}. +Note that when nonfatal I/O is enabled (@pxref{Nonfatal}), +@command{gawk} only tries to open a TCP/IP socket once. @item POSIXLY_CORRECT Causes @command{gawk} to switch to POSIX-compatibility @@ -4504,14 +4514,6 @@ two regexp matchers that @command{gawk} uses internally. (There aren't supposed to be differences, but occasionally theory and practice don't coordinate with each other.) -@item GAWK_NO_PP_RUN -When @command{gawk} is invoked with the @option{--pretty-print} option, -it will not run the program if this environment variable exists. - -@quotation CAUTION -This variable will not survive into the next major release. -@end quotation - @item GAWK_STACKSIZE This specifies the amount by which @command{gawk} should grow its internal evaluation stack, when needed. @@ -4809,6 +4811,13 @@ Similarly, you may use @code{print} or @code{printf} statements in the @var{init} and @var{increment} parts of a @code{for} loop. This is another long-undocumented ``feature'' of Unix @command{awk}. +@command{gawk} lets you use the names of built-in functions that are +@command{gawk} extensions as the names of parameters in user-defined functions. +This is intended to ``future-proof'' old code that happens to use +function names added by @command{gawk} after the code was written. +Standard @command{awk} built-in functions, such as @code{sin()} or +@code{substr()} are @emph{not} shadowed in this way. + @end ignore @node Invoking Summary @@ -5091,17 +5100,21 @@ between @samp{0} and @samp{7}. For example, the code for the ASCII ESC @item \x@var{hh}@dots{} The hexadecimal value @var{hh}, where @var{hh} stands for a sequence of hexadecimal digits (@samp{0}--@samp{9}, and either @samp{A}--@samp{F} -or @samp{a}--@samp{f}). Like the same construct -in ISO C, the escape sequence continues until the first nonhexadecimal -digit is seen. @value{COMMONEXT} -However, using more than two hexadecimal digits produces -undefined results. (The @samp{\x} escape sequence is not allowed in -POSIX @command{awk}.) +or @samp{a}--@samp{f}). A maximum of two digts are allowed after +the @samp{\x}. Any further hexadecimal digits are treated as simple +letters or numbers. @value{COMMONEXT} +(The @samp{\x} escape sequence is not allowed in POSIX awk.) @quotation CAUTION -The next major release of @command{gawk} will change, such -that a maximum of two hexadecimal digits following the -@samp{\x} will be used. +In ISO C, the escape sequence continues until the first nonhexadecimal +digit is seen. +For many years, @command{gawk} would continue incorporating +hexadecimal digits into the value until a non-hexadecimal digit +or the end of the string was encountered. +However, using more than two hexadecimal digits produced +undefined results. +As of @value{PVERSION} 4.2, only two digits +are processed. @end quotation @cindex @code{\} (backslash), @code{\/} escape sequence @@ -6107,6 +6120,7 @@ used with it do not have to be named on the @command{awk} command line * Getline:: Reading files under explicit program control using the @code{getline} function. * Read Timeout:: Reading input with a timeout. +* Retrying Input:: Retrying input after certain errors. * Command-line directories:: What happens if you put a directory on the command line. * Input Summary:: Input summary. @@ -7714,6 +7728,13 @@ a record, such as a file that cannot be opened, then @code{getline} returns @minus{}1. In this case, @command{gawk} sets the variable @code{ERRNO} to a string describing the error that occurred. +If @code{ERRNO} indicates that the I/O operation may be +retried, and @code{PROCINFO["@var{input}", "RETRY"]} is set, +then @code{getline} returns @minus{}2 +instead of @minus{}1, and further calls to @code{getline} +may be attemped. @DBXREF{Retrying Input} for further information about +this feature. + In the following examples, @var{command} stands for a string value that represents a shell command. @@ -8368,7 +8389,8 @@ on a per-command or per-connection basis. the attempt to read from the underlying device may succeed in a later attempt. This is a limitation, and it also means that you cannot use this to multiplex input from -two or more sources. +two or more sources. @DBXREF{Retrying Input} for a way to enable +later I/O attempts to succeed. Assigning a timeout value prevents read operations from blocking indefinitely. But bear in mind that there are other ways @@ -8378,6 +8400,36 @@ a connection before it can start reading any data, or the attempt to open a FIFO special file for reading can block indefinitely until some other process opens it for writing. +@node Retrying Input +@section Retrying Reads After Certain Input Errors +@cindex retrying input + +@cindex differences in @command{awk} and @command{gawk}, retrying input +This @value{SECTION} describes a feature that is specific to @command{gawk}. + +When @command{gawk} encounters an error while reading input, by +default @code{getline} returns @minus{}1, and subsequent attempts to +read from that file result in an end-of-file indication. However, you +may optionally instruct @command{gawk} to allow I/O to be retried when +certain errors are encountered by setting a special element in +the @code{PROCINFO} array (@pxref{Auto-set}): + +@example +PROCINFO["@var{input_name}", "RETRY"] = 1 +@end example + +When this element exists, @command{gawk} checks the value of the system +(C language) +@code{errno} variable when an I/O error occurs. If @code{errno} indicates +a subsequent I/O attempt may succeed, @code{getline} instead returns +@minus{}2 and +further calls to @code{getline} may succeed. This applies to the @code{errno} +values @code{EAGAIN}, @code{EWOULDBLOCK}, @code{EINTR}, or @code{ETIMEDOUT}. + +This feature is useful in conjunction with +@code{PROCINFO["@var{input_name}", "READ_TIMEOUT"]} or situations where a file +descriptor has been configured to behave in a non-blocking fashion. + @node Command-line directories @section Directories on the Command Line @cindex differences in @command{awk} and @command{gawk}, command-line directories @@ -8539,6 +8591,7 @@ and discusses the @code{close()} built-in function. @command{gawk} allows access to inherited file descriptors. * Close Files And Pipes:: Closing Input and Output Files and Pipes. +* Nonfatal:: Enabling Nonfatal Output. * Output Summary:: Output summary. * Output Exercises:: Exercises. @end menu @@ -9941,6 +9994,71 @@ when closing a pipe. @end sidebar +@node Nonfatal +@section Enabling Nonfatal Output + +This @value{SECTION} describes a @command{gawk}-specific feature. + +In standard @command{awk}, output with @code{print} or @code{printf} +to a nonexistent file, or some other I/O error (such as filling up the +disk) is a fatal error. + +@example +$ @kbd{gawk 'BEGIN @{ print "hi" > "/no/such/file" @}'} +@error{} gawk: cmd. line:1: fatal: can't redirect to `/no/such/file' (No such file or directory) +@end example + +@command{gawk} makes it possible to detect that an error has +occurred, allowing you to possibly recover from the error, or +at least print an error message of your choosing before exiting. +You can do this in one of two ways: + +@itemize @bullet +@item +For all output files, by assigning any value to @code{PROCINFO["NONFATAL"]}. + +@item +On a per-file basis, by assigning any value to +@code{PROCINFO[@var{filename}, "NONFATAL"]}. +Here, @var{filename} is the name of the file to which +you wish output to be nonfatal. +@end itemize + +Once you have enabled nonfatal output, you must check @code{ERRNO} +after every relevant @code{print} or @code{printf} statement to +see if something went wrong. It is also a good idea to initialize +@code{ERRNO} to zero before attempting the output. For example: + +@example +$ @kbd{gawk '} +> @kbd{BEGIN @{} +> @kbd{ PROCINFO["NONFATAL"] = 1} +> @kbd{ ERRNO = 0} +> @kbd{ print "hi" > "/no/such/file"} +> @kbd{ if (ERRNO) @{} +> @kbd{ print("Output failed:", ERRNO) > "/dev/stderr"} +> @kbd{ exit 1} +> @kbd{ @}} +> @kbd{@}'} +@error{} Output failed: No such file or directory +@end example + +Here, @command{gawk} did not produce a fatal error; instead +it let the @command{awk} program code detect the problem and handle it. + +This mechanism works also for standard output and standard error. +For standard output, you may use @code{PROCINFO["-", "NONFATAL"]} +or @code{PROCINFO["/dev/stdout", "NONFATAL"]}. For standard error, use +@code{PROCINFO["/dev/stderr", "NONFATAL"]}. + +When attempting to open a TCP/IP socket (@pxref{TCP/IP Networking}), +@command{gawk} tries multiple times. The @env{GAWK_SOCK_RETRIES} +environment variable (@pxref{Other Environment Variables}) allows you to +override @command{gawk}'s builtin default number of attempts. However, +once nonfatal I/O is enabled for a given socket, @command{gawk} only +retries once, relying on @command{awk}-level code to notice that there +was a problem. + @node Output Summary @section Summary @@ -9969,6 +10087,12 @@ Use @code{close()} to close open file, pipe, and coprocess redirections. For coprocesses, it is possible to close only one direction of the communications. +@item +Normally errors with @code{print} or @code{printf} are fatal. +@command{gawk} lets you make output errors be nonfatal either for +all files or on a per-file basis. You must then check for errors +after every relevant output statement. + @end itemize @c EXCLUDE START @@ -14134,10 +14258,24 @@ opens the next file. An associative array containing the values of the environment. The array indices are the environment variable names; the elements are the values of the particular environment variables. For example, -@code{ENVIRON["HOME"]} might be @code{"/home/arnold"}. Changing this array -does not affect the environment passed on to any programs that -@command{awk} may spawn via redirection or the @code{system()} function. -(In a future version of @command{gawk}, it may do so.) +@code{ENVIRON["HOME"]} might be @code{/home/arnold}. + +For POSIX @command{awk}, changing this array does not affect the +environment passed on to any programs that @command{awk} may spawn via +redirection or the @code{system()} function. + +However, beginning with version 4.2, if not in POSIX +compatibility mode, @command{gawk} does update its own environment when +@code{ENVIRON} is changed, thus changing the environment seen by programs +that it creates. You should therefore be especially careful if you +modify @code{ENVIRON["PATH"]}, which is the search path for finding +executable programs. + +This can also affect the running @command{gawk} program, since some of the +built-in functions may pay attention to certain environment variables. +The most notable instance of this is @code{mktime()} (@pxref{Time +Functions}), which pays attention the value of the @env{TZ} environment +variable on many systems. Some operating systems may not have environment variables. On such systems, the @code{ENVIRON} array is empty (except for @@ -14171,6 +14309,11 @@ value to be meaningful when an I/O operation returns a failure value, such as @code{getline} returning @minus{}1. You are, of course, free to clear it yourself before doing an I/O operation. +If the value of @code{ERRNO} corresponds to a system error in the C +@code{errno} variable, then @code{PROCINFO["errno"]} will be set to the value +of @code{errno}. For non-system errors, @code{PROCINFO["errno"]} will +be zero. + @cindex @code{FILENAME} variable @cindex dark corner, @code{FILENAME} variable @item @code{FILENAME} @@ -14239,6 +14382,10 @@ are guaranteed to be available: @item PROCINFO["egid"] The value of the @code{getegid()} system call. +@item PROCINFO["errno"] +The value of the C @code{errno} variable when @code{ERRNO} is set to +the associated error message. + @item PROCINFO["euid"] @cindex effective user ID of @command{gawk} user The value of the @code{geteuid()} system call. @@ -14378,6 +14525,11 @@ open input file, pipe, or coprocess. @DBXREF{Read Timeout} for more information. @item +It may be used to indicate that input may be retried when it fails due to +certain errors. +@DBXREF{Retrying Input} for more information. + +@item It may be used to cause coprocesses to communicate over pseudo-ttys instead of through two-way pipes; this is discussed further in @ref{Two-way I/O}. @@ -16246,6 +16398,23 @@ truncated toward zero. For example, @code{int(3)} is 3, @code{int(3.9)} is 3, @code{int(-3.9)} is @minus{}3, and @code{int(-3)} is @minus{}3 as well. +@item @code{intdiv(@var{numerator}, @var{denominator}, @var{result})} +@cindexawkfunc{intdiv} +@cindex intdiv +Perform integer division, similar to the standard C function of the +same name. First, truncate @code{numerator} and @code{denominator} +towards zero, creating integer values. Clear the @code{result} +array, and then set @code{result["quotient"]} to the result of +@samp{numerator / denominator}, truncated towards zero to an integer, +and set @code{result["remainder"]} to the result of @samp{numerator % +denominator}, truncated towards zero to an integer. This function is +primarily intended for use with arbitrary length integers; it avoids +creating MPFR arbitrary precision floating-point values (@pxref{Arbitrary +Precision Integers}). + +This function is a @code{gawk} extension. It is not available in +compatibility mode (@pxref{Options}). + @item @code{log(@var{x})} @cindexawkfunc{log} @cindex logarithm @@ -26856,8 +27025,7 @@ The profiled version of your program may not look exactly like what you typed when you wrote it. This is because @command{gawk} creates the profiled version by ``pretty-printing'' its internal representation of the program. The advantage to this is that @command{gawk} can produce -a standard representation. The disadvantage is that all source code -comments are lost. +a standard representation. Also, things such as: @example @@ -26951,10 +27119,26 @@ When called this way, @command{gawk} ``pretty-prints'' the program into @file{awkprof.out}, without any execution counts. @quotation NOTE -The @option{--pretty-print} option still runs your program. -This will change in the next major release. +Once upon a time, the @option{--pretty-print} option would also run +your program. This is is no longer the case. @end quotation +There is a significant difference between the output created when +profiling, and that created when pretty-printing. Pretty-printed output +preserves the original comments that were in the program, although their +placement may not correspond exactly to their original locations in the +source code. + +However, as a deliberate design decision, profiling output @emph{omits} +the original program's comments. This allows you to focus on the +execution count data and helps you avoid the temptation to use the +profiler for pretty-printing. + +Additionally, pretty-printed output does not have the leading indentation +that the profiling output does. This makes it easy to pretty-print your +code once development is completed, and then use the result as the final +version of your program. + @node Advanced Features Summary @section Summary @@ -30028,6 +30212,122 @@ to just use the following: gawk -M 'BEGIN @{ n = 13; print n % 2 @}' @end example +When dividing two arbitrary precision integers with either +@samp{/} or @samp{%}, the result is typically an arbitrary +precision floating point value (unless the denominator evenly +divides into the numerator). In order to do integer division +or remainder with arbitrary precision integers, use the built-in +@code{intdiv()} function (@pxref{Numeric Functions}). + +You can simulate the @code{intdiv()} function in standard @command{awk} +using this user-defined function: + +@example +@c file eg/lib/intdiv.awk +# intdiv --- do integer division + +@c endfile +@ignore +@c file eg/lib/intdiv.awk +# +# Arnold Robbins, arnold@@skeeve.com, Public Domain +# July, 2014 +# +# Name changed from div() to intdiv() +# April, 2015 + +@c endfile + +@end ignore +@c file eg/lib/intdiv.awk +function intdiv(numerator, denominator, result) +@{ + split("", result) + + numerator = int(numerator) + denominator = int(denominator) + result["quotient"] = int(numerator / denominator) + result["remainder"] = int(numerator % denominator) + + return 0.0 +@} +@c endfile +@end example + +The following example program, contributed by Katie Wasserman, +uses @code{intdiv()} to +compute the digits of @value{PI} to as many places as you +choose to set: + +@example +@c file eg/prog/pi.awk +# pi.awk --- compute the digits of pi +@c endfile +@c endfile +@ignore +@c file eg/prog/pi.awk +# +# Katie Wasserman, katie@@wass.net +# August 2014 +@c endfile +@end ignore +@c file eg/prog/pi.awk + +BEGIN @{ + digits = 100000 + two = 2 * 10 ^ digits + pi = two + for (m = digits * 4; m > 0; --m) @{ + d = m * 2 + 1 + x = pi * m + intdiv(x, d, result) + pi = result["quotient"] + pi = pi + two + @} + print pi +@} +@c endfile +@end example + +@ignore +Date: Wed, 20 Aug 2014 10:19:11 -0400 +To: arnold@skeeve.com +From: Katherine Wasserman <katie@wass.net> +Subject: Re: computation of digits of pi? + +Arnold, + +>The program that you sent to compute the digits of pi using div(). Is +>that some standard algorithm that every math student knows? If so, +>what's it called? + +It's not that well known but it's not that obscure either + +It's Euler's modification to Newton's method for calculating pi. + +Take a look at lines (23) - (25) here: http://mathworld.wolfram.com/PiFormulas.htm + +The algorithm I wrote simply expands the multiply by 2 and works from the innermost expression outwards. I used this to program HP calculators because it's quite easy to modify for tiny memory devices with smallish word sizes. + +http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=899 + +-Katie +@end ignore + +When asked about the algorithm used, Katie replied: + +@quotation +It's not that well known but it's not that obscure either. +It's Euler's modification to Newton's method for calculating pi. +Take a look at lines (23) - (25) here: @uref{http://mathworld.wolfram.com/PiFormulas.html}. + +The algorithm I wrote simply expands the multiply by 2 and works from +the innermost expression outwards. I used this to program HP calculators +because it's quite easy to modify for tiny memory devices with smallish +word sizes. See +@uref{http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=899}. +@end quotation + @node POSIX Floating Point Problems @section Standards Versus Existing Practice @@ -30445,6 +30745,7 @@ This (rather large) @value{SECTION} describes the API in detail. * Symbol Table Access:: Functions for accessing global variables. * Array Manipulation:: Functions for working with arrays. +* Redirection API:: How to access and manipulate redirections. * Extension API Variables:: Variables provided by the API. * Extension API Boilerplate:: Boilerplate code for using the API. @end menu @@ -30520,6 +30821,10 @@ Clearing an array @item Flattening an array for easy C-style looping over all its indices and elements @end itemize + +@item +Accessing and manipulating redirections. + @end itemize Some points about using the API: @@ -32490,6 +32795,75 @@ $ @kbd{AWKLIBPATH=$PWD ./gawk -f subarray.awk} (@DBXREF{Finding Extensions} for more information on the @env{AWKLIBPATH} environment variable.) +@node Redirection API +@subsection Accessing and Manipulating Redirections + +The following function allows extensions to access and manipulate redirections. + +@table @code +@item awk_bool_t get_file(const char *name, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ size_t name_len, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const char *filetype, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ int fd, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const awk_input_buf_t **ibufp, +@itemx @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ const awk_output_buf_t **obufp); +Look up a file in @command{gawk}'s internal redirection table. +If @code{name} is @code{NULL} or @code{name_len} is zero, return +data for the currently open input file corresponding to @code{FILENAME}. +(This does not access the @code{filetype} argument, so that may be undefined). +If the file is not already open, attempt to open it. +The @code{filetype} argument must be zero-terminated and should be one of: + +@table @code +@item ">" +A file opened for output. + +@item ">>" +A file opened for append. + +@item "<" +A file opened for input. + +@item "|>" +A pipe opened for output. + +@item "|<" +A pipe opened for input. + +@item "|&" +A two-way coprocess. +@end table + +On error, return a @code{false} value. Otherwise, return +@code{true}, and return additional information about the redirection +in the @code{ibufp} and @code{obufp} pointers. For input +redirections, the @code{*ibufp} value should be non-@code{NULL}, +and @code{*obufp} should be @code{NULL}. For output redirections, +the @code{*obufp} value should be non-@code{NULL}, and @code{*ibufp} +should be @code{NULL}. For two-way coprocesses, both values should +be non-@code{NULL}. + +In the usual case, the extension is interested in @code{(*ibufp)->fd} +and/or @code{fileno((*obufp)->fp)}. If the file is not already +open, and the @code{fd} argument is non-negative, @command{gawk} +will use that file descriptor instead of opening the file in the +usual way. If @code{fd} is non-negative, but the file exists already, +@command{gawk} ignores @code{fd} and returns the existing file. It is +the caller's responsibility to notice that neither the @code{fd} in +the returned @code{awk_input_buf_t} nor the @code{fd} in the returned +@code{awk_output_buf_t} matches the requested value. + +Note that supplying a file descriptor is currently @emph{not} supported +for pipes. However, supplying a file descriptor should work for input, +output, append, and two-way (coprocess) sockets. If @code{filetype} +is two-way, @command{gawk} assumes that it is a socket! Note that in +the two-way case, the input and output file descriptors may differ. +To check for success, you must check whether either matches. +@end table + +It is anticipated that this API function will be used to implement I/O +multiplexing and a socket library. + @node Extension API Variables @subsection API Variables @@ -34031,18 +34405,21 @@ As of this writing, there are seven extensions: GD graphics library extension @item +MPFR library extension +(this provides access to a number of MPFR functions that @command{gawk}'s +native MPFR support does not) + +@item PDF extension @item PostgreSQL extension @item -MPFR library extension -(this provides access to a number of MPFR functions that @command{gawk}'s -native MPFR support does not) +Redis extension @item -Redis extension +Select extension @item XML parser extension, using the @uref{http://expat.sourceforge.net, Expat} @@ -34671,6 +35048,10 @@ Indirect function calls @item Directories on the command line produce a warning and are skipped (@pxref{Command-line directories}) + +@item +Output with @code{print} and @code{printf} need not be fatal +(@pxref{Nonfatal}) @end itemize @item @@ -34758,6 +35139,11 @@ The @code{isarray()} function to check if a variable is an array or not The @code{bindtextdomain()}, @code{dcgettext()}, and @code{dcngettext()} functions for internationalization (@pxref{Programmer i18n}) + +@item +The @code{intdiv()} function for doing integer +division and remainder +(@pxref{Numeric Functions}) @end itemize @item @@ -34890,6 +35276,16 @@ for @command{gawk} @value{PVERSION} 4.1: Ultrix @end itemize +@item +Support for the following systems was removed from the code +for @command{gawk} @value{PVERSION} 4.2: + +@c nested table +@itemize @value{MINUS} +@item +MirBSD +@end itemize + @end itemize @c XXX ADD MORE STUFF HERE @@ -35511,6 +35907,44 @@ Redirected @code{getline} became allowed inside The @code{where} command was added to the debugger (@pxref{Execution Stack}). +@item +Support for Ultrix was removed. + +@end itemize + +Version 4.2 introduced the following changes: + +@itemize @bullet +@item +Changes to @code{ENVIRON} are reflected into @command{gawk}'s +environment and that of programs that it runs. +@xref{Auto-set}. + +@item +The @option{--pretty-print} option no longer runs the @command{awk} +program too. +@xref{Options}. + +@item +The @command{igawk} program and its manual page are no longer +installed when @command{gawk} is built. +@xref{Igawk Program}. + +@item +The @code{intdiv()} function. +@xref{Numeric Functions}. + +@item +The maximum number of hexdecimal digits in @samp{\x} escapes +is now two. +@xref{Escape Sequences}. + +@item +Nonfatal output with @code{print} and @code{printf}. +@xref{Nonfatal}. + +@item +Support for MirBSD was removed. @end itemize @c XXX ADD MORE STUFF HERE @@ -36177,6 +36611,8 @@ The generated Info file for The @command{troff} source for a manual page describing the @command{igawk} program presented in @ref{Igawk Program}. +(Since @command{gawk} can do its own @code{@@include} processing, +neither @command{igawk} nor @file{igawk.1} are installed.) @item doc/Makefile.in The input file used during the configuration process to generate the @@ -36221,8 +36657,6 @@ source file for this @value{DOCUMENT}. It also contains a @file{Makefile.in} fil @file{Makefile.am} is used by GNU Automake to create @file{Makefile.in}. The library functions from @ref{Library Functions}, -and the @command{igawk} program from -@DBREF{Igawk Program} are included as ready-to-use files in the @command{gawk} distribution. They are installed as part of the installation process. The rest of the programs in this @value{DOCUMENT} are available in appropriate @@ -36233,6 +36667,12 @@ The source code, manual pages, and infrastructure files for the sample extensions included with @command{gawk}. @xref{Dynamic Extensions}, for more information. +@item extras/* +Additional non-essential files. Currently, this directory contains some shell +startup files to be installed in @file{/etc/profile.d} to aid in manipulating +the @env{AWKPATH} and @env{AWKLIBPATH} environment variables. +@xref{Shell Startup Files}, for more information. + @item posix/* Files needed for building @command{gawk} on POSIX-compliant systems. @@ -36264,6 +36704,7 @@ to configure @command{gawk} for your system yourself. @menu * Quick Installation:: Compiling @command{gawk} under Unix. +* Shell Startup Files:: Shell convenience functions. * Additional Configuration Options:: Other compile-time options. * Configuration Philosophy:: How it's all supposed to work. @end menu @@ -36344,6 +36785,44 @@ is likely that you will be asked for your password, and you will have to have been set up previously as a user who is allowed to run the @command{sudo} command. +@node Shell Startup Files +@appendixsubsec Shell Startup Files + +The distribution contains shell startup files @file{gawk.sh} and +@file{gawk.csh} containing functions to aid in manipulating +the @env{AWKPATH} and @env{AWKLIBPATH} environment variables. +On a Fedora system, these files should be installed in @file{/etc/profile.d}; +on other platforms, the appropriate location may be different. + +@table @command + +@cindex @command{gawkpath_default} shell function +@item gawkpath_default +Reset the @env{AWKPATH} environment variable to its default value. + +@cindex @command{gawkpath_prepend} shell function +@item gawkpath_prepend +Add the argument to the front of the @env{AWKPATH} environment variable. + +@cindex @command{gawkpath_append} shell function +@item gawkpath_append +Add the argument to the end of the @env{AWKPATH} environment variable. + +@cindex @command{gawklibpath_default} shell function +@item gawklibpath_default +Reset the @env{AWKLIBPATH} environment variable to its default value. + +@cindex @command{gawklibpath_prepend} shell function +@item gawklibpath_prepend +Add the argument to the front of the @env{AWKLIBPATH} environment variable. + +@cindex @command{gawklibpath_append} shell function +@item gawklibpath_append +Add the argument to the end of the @env{AWKLIBPATH} environment variable. + +@end table + + @node Additional Configuration Options @appendixsubsec Additional Configuration Options @cindex @command{gawk}, configuring, options |