diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/ChangeLog | 19 | ||||
| -rw-r--r-- | doc/gawk.1 | 45 | ||||
| -rw-r--r-- | doc/gawk.info | 1340 | ||||
| -rw-r--r-- | doc/gawk.texi | 115 | ||||
| -rw-r--r-- | doc/gawktexi.in | 115 |
5 files changed, 1022 insertions, 612 deletions
diff --git a/doc/ChangeLog b/doc/ChangeLog index 27dca3dc..19948706 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -36,6 +36,25 @@ * gawkinet.texi: Fix capitalization in document title. * gawktexi.in: Here we again: Starting on more O'Reilly fixes. +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. @@ -942,6 +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, @@ -1103,6 +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) @@ -1221,6 +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 +.BR 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 @@ -2289,6 +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. diff --git a/doc/gawk.info b/doc/gawk.info index 1c74fc99..e399353b 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. @@ -557,6 +558,7 @@ 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 @@ -4170,6 +4172,7 @@ 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. @@ -5440,7 +5443,11 @@ how `awk' works. encounters the end of the file. If there is some error in getting a 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. +describing the error that occurred. If the `errno' variable indicates +that the I/O operation may be retried, and `PROCINFO["input", "RETRY"]' +is set, then -2 will be returned 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. @@ -5878,7 +5885,7 @@ 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 ================================= @@ -5957,7 +5964,8 @@ 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 @@ -5972,9 +5980,36 @@ 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 Directories on the Command Line +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, it will by +default return -1 from getline, and subsequent attempts to read from +that file will 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 setting a special element in the +`PROCINFO' array (*note Auto-set::): + + PROCINFO["input_name", "RETRY"] + + When set, this causes `gawk' to check the value of the system +`errno' variable when an I/O error occurs. If `errno' indicates a +subsequent I/O attempt may succeed, `getline' will instead return -2 and +further calls to `getline' may succeed. This applies to `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 + +4.12 Directories on the Command Line ==================================== According to the POSIX standard, files named on the `awk' command line @@ -5997,7 +6032,7 @@ 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 @@ -6071,7 +6106,7 @@ 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 @@ -10367,6 +10402,11 @@ 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 @@ -10415,6 +10455,10 @@ 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. @@ -10525,6 +10569,10 @@ 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::. @@ -22896,6 +22944,7 @@ 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. @@ -22956,6 +23005,9 @@ 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 @@ -24162,7 +24214,7 @@ 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 -------------------------- @@ -24647,9 +24699,72 @@ array: environment variable.) -File: gawk.info, Node: Extension API Variables, Next: Extension API Boilerplate, Prev: Array Manipulation, Up: Extension API Description - -16.4.12 API Variables +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 0, it returns data for the currently open + input file corresponding to `FILENAME' (and it will not access the + `filetype' argument, so that may be undefined). If the file is + not already open, it tries to open it. The `filetype' argument + must be NUL-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, a `false' value is returned. Otherwise, the return + status is `true', and additional information about the redirection + is returned 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 the fd is + non-negative, but the file exists already, `gawk' ignores the 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. It should work for input, + output, append, and two-way (coprocess) sockets. If `filetype' is + two-way, we assume that it is a socket! Note that in the two-way + case, the input and output file descriptors may differ. To check + for success, one 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 + +16.4.13 API Variables --------------------- The API provides two sets of variables. The first provides information @@ -24666,7 +24781,7 @@ 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 @@ -24715,7 +24830,7 @@ 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 @@ -24750,7 +24865,7 @@ 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 @@ -32414,9 +32529,9 @@ Index (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 104) +* 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 328) +* 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) @@ -32610,7 +32725,7 @@ Index * 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 130) +* 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) @@ -32633,7 +32748,7 @@ 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 144) +* 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) @@ -32641,9 +32756,11 @@ 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 279) +* 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. @@ -32651,7 +32768,7 @@ 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 283) +* differences in awk and gawk, SYMTAB variable: Auto-set. (line 296) * differences in awk and gawk, TEXTDOMAIN variable: User-modified. (line 152) * differences in awk and gawk, trunc-mod operation: Arithmetic Ops. @@ -32692,8 +32809,8 @@ Index * 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 149) -* effective user ID of gawk user: Auto-set. (line 153) +* 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) @@ -32808,7 +32925,7 @@ Index (line 6) * extension API version: Extension Versioning. (line 6) -* extension API, version number: Auto-set. (line 246) +* extension API, version number: Auto-set. (line 255) * extension example: Extension Example. (line 6) * extension registration: Registration Functions. (line 6) @@ -32889,7 +33006,7 @@ 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 104) +* 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) @@ -32957,9 +33074,9 @@ Index * flush buffered output: I/O Functions. (line 28) * fnmatch() extension function: Extension Sample Fnmatch. (line 12) -* FNR variable <1>: Auto-set. (line 114) +* FNR variable <1>: Auto-set. (line 119) * FNR variable: Records. (line 6) -* FNR variable, changing: Auto-set. (line 328) +* 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. @@ -33009,7 +33126,7 @@ Index * FSF (Free Software Foundation): Manual History. (line 6) * fts() extension function: Extension Sample File Functions. (line 61) -* FUNCTAB array: Auto-set. (line 130) +* 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) @@ -33059,7 +33176,7 @@ Index * G-d: Acknowledgments. (line 94) * Garfinkle, Scott: Contributors. (line 34) * gawk program, dynamic profiling: Profiling. (line 178) -* gawk version: Auto-set. (line 221) +* 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) @@ -33094,7 +33211,7 @@ 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 130) +* 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. @@ -33126,7 +33243,7 @@ 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 144) +* gawk, PROCINFO array in: Auto-set. (line 149) * gawk, regexp constants and: Using Constant Regexps. (line 28) * gawk, regular expressions, case sensitivity: Case-sensitivity. @@ -33134,14 +33251,14 @@ 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 279) +* 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 283) +* gawk, SYMTAB array in: Auto-set. (line 296) * gawk, TEXTDOMAIN variable in: User-modified. (line 152) * gawk, timestamps: Time Functions. (line 6) * gawk, uses for: Preface. (line 34) @@ -33233,7 +33350,7 @@ 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 194) +* 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. @@ -33528,7 +33645,7 @@ Index * mawk utility <3>: Concatenation. (line 36) * mawk utility <4>: Getline/Pipe. (line 62) * mawk utility: Escape Sequences. (line 120) -* maximum precision supported by MPFR library: Auto-set. (line 235) +* 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) @@ -33541,7 +33658,7 @@ Index * messages from extensions: Printing Messages. (line 6) * metacharacters in regular expressions: Regexp Operators. (line 6) * metacharacters, escape sequences for: Escape Sequences. (line 139) -* minimum precision supported by MPFR library: Auto-set. (line 238) +* minimum precision supported 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) @@ -33590,7 +33707,7 @@ Index (line 47) * nexti debugger command: Debugger Execution Control. (line 49) -* NF variable <1>: Auto-set. (line 119) +* 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. @@ -33599,9 +33716,9 @@ Index * non-existent array elements: Reference to Elements. (line 23) * not Boolean-logic operator: Boolean Ops. (line 6) -* NR variable <1>: Auto-set. (line 139) +* NR variable <1>: Auto-set. (line 144) * NR variable: Records. (line 6) -* NR variable, changing: Auto-set. (line 328) +* 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. @@ -33715,7 +33832,7 @@ 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 203) +* 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) @@ -33881,24 +33998,24 @@ 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 idIDof gawk process: Auto-set. (line 197) -* process ID of gawk process: Auto-set. (line 200) +* process group idIDof 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 144) +* 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 256) +* 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 178) -* program identifiers: Auto-set. (line 162) +* program identifiers: Auto-set. (line 171) * program, definition of: Getting Started. (line 21) * programming conventions, --non-decimal-data option: Nondecimal Data. (line 35) @@ -34033,6 +34150,7 @@ 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) @@ -34056,7 +34174,7 @@ 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 266) +* 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 70) @@ -34082,9 +34200,9 @@ 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 272) +* RSTART variable: Auto-set. (line 285) * RSTART variable, match() function and: String Functions. (line 228) -* RT variable <1>: Auto-set. (line 279) +* 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) @@ -34104,7 +34222,7 @@ Index * 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 311) +* Schorr, Andrew <2>: Auto-set. (line 324) * Schorr, Andrew: Acknowledgments. (line 60) * Schreiber, Bert: Acknowledgments. (line 38) * Schreiber, Rita: Acknowledgments. (line 38) @@ -34187,7 +34305,7 @@ Index (line 106) * sidebar, Changing FS Does Not Affect the Fields: Full Line Fields. (line 14) -* sidebar, Changing NR and FNR: Auto-set. (line 326) +* 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. @@ -34349,9 +34467,9 @@ 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 251) +* supplementary groups of gawk process: Auto-set. (line 260) * switch statement: Switch Statement. (line 6) -* SYMTAB array: Auto-set. (line 283) +* SYMTAB array: Auto-set. (line 296) * syntactic ambiguity: /= operator vs. /=.../ regexp constant: Assignment Ops. (line 148) * system: I/O Functions. (line 107) @@ -34528,10 +34646,10 @@ Index * variables, uninitialized, as array subscripts: Uninitialized Subscripts. (line 6) * variables, user-defined: Variables. (line 6) -* version of gawk: Auto-set. (line 221) -* version of gawk extension API: Auto-set. (line 246) -* version of GNU MP library: Auto-set. (line 232) -* version of GNU MPFR library: Auto-set. (line 228) +* 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) @@ -34621,560 +34739,562 @@ Index Tag Table: Node: Top1204 -Node: Foreword342225 -Node: Foreword446669 -Node: Preface48200 -Ref: Preface-Footnote-151071 -Ref: Preface-Footnote-251178 -Ref: Preface-Footnote-351411 -Node: History51553 -Node: Names53904 -Ref: Names-Footnote-154997 -Node: This Manual55143 -Ref: This Manual-Footnote-161643 -Node: Conventions61743 -Node: Manual History64080 -Ref: Manual History-Footnote-167073 -Ref: Manual History-Footnote-267114 -Node: How To Contribute67188 -Node: Acknowledgments68317 -Node: Getting Started73134 -Node: Running gawk75573 -Node: One-shot76763 -Node: Read Terminal78027 -Node: Long80058 -Node: Executable Scripts81571 -Ref: Executable Scripts-Footnote-184360 -Node: Comments84463 -Node: Quoting86945 -Node: DOS Quoting92463 -Node: Sample Data Files93138 -Node: Very Simple95733 -Node: Two Rules100632 -Node: More Complex102518 -Node: Statements/Lines105380 -Ref: Statements/Lines-Footnote-1109835 -Node: Other Features110100 -Node: When111036 -Ref: When-Footnote-1112790 -Node: Intro Summary112855 -Node: Invoking Gawk113739 -Node: Command Line115253 -Node: Options116051 -Ref: Options-Footnote-1131846 -Ref: Options-Footnote-2132075 -Node: Other Arguments132100 -Node: Naming Standard Input135048 -Node: Environment Variables136141 -Node: AWKPATH Variable136699 -Ref: AWKPATH Variable-Footnote-1140106 -Ref: AWKPATH Variable-Footnote-2140151 -Node: AWKLIBPATH Variable140411 -Node: Other Environment Variables141667 -Node: Exit Status145185 -Node: Include Files145861 -Node: Loading Shared Libraries149450 -Node: Obsolete150877 -Node: Undocumented151569 -Node: Invoking Summary151836 -Node: Regexp153499 -Node: Regexp Usage154953 -Node: Escape Sequences156990 -Node: Regexp Operators163230 -Ref: Regexp Operators-Footnote-1170640 -Ref: Regexp Operators-Footnote-2170787 -Node: Bracket Expressions170885 -Ref: table-char-classes172900 -Node: Leftmost Longest175842 -Node: Computed Regexps177144 -Node: GNU Regexp Operators180573 -Node: Case-sensitivity184245 -Ref: Case-sensitivity-Footnote-1187130 -Ref: Case-sensitivity-Footnote-2187365 -Node: Regexp Summary187473 -Node: Reading Files188940 -Node: Records191033 -Node: awk split records191766 -Node: gawk split records196695 -Ref: gawk split records-Footnote-1201234 -Node: Fields201271 -Ref: Fields-Footnote-1204049 -Node: Nonconstant Fields204135 -Ref: Nonconstant Fields-Footnote-1206373 -Node: Changing Fields206576 -Node: Field Separators212507 -Node: Default Field Splitting215211 -Node: Regexp Field Splitting216328 -Node: Single Character Fields219678 -Node: Command Line Field Separator220737 -Node: Full Line Fields223954 -Ref: Full Line Fields-Footnote-1225475 -Ref: Full Line Fields-Footnote-2225521 -Node: Field Splitting Summary225622 -Node: Constant Size227696 -Node: Splitting By Content232279 -Ref: Splitting By Content-Footnote-1236244 -Node: Multiple Line236407 -Ref: Multiple Line-Footnote-1242288 -Node: Getline242467 -Node: Plain Getline244674 -Node: Getline/Variable247314 -Node: Getline/File248463 -Node: Getline/Variable/File249848 -Ref: Getline/Variable/File-Footnote-1251451 -Node: Getline/Pipe251538 -Node: Getline/Variable/Pipe254216 -Node: Getline/Coprocess255347 -Node: Getline/Variable/Coprocess256611 -Node: Getline Notes257350 -Node: Getline Summary260144 -Ref: table-getline-variants260556 -Node: Read Timeout261385 -Ref: Read Timeout-Footnote-1265222 -Node: Command-line directories265280 -Node: Input Summary266185 -Node: Input Exercises269570 -Node: Printing270298 -Node: Print272075 -Node: Print Examples273532 -Node: Output Separators276311 -Node: OFMT278329 -Node: Printf279684 -Node: Basic Printf280469 -Node: Control Letters282041 -Node: Format Modifiers286026 -Node: Printf Examples292036 -Node: Redirection294522 -Node: Special FD301360 -Ref: Special FD-Footnote-1304526 -Node: Special Files304600 -Node: Other Inherited Files305217 -Node: Special Network306217 -Node: Special Caveats307079 -Node: Close Files And Pipes308028 -Ref: Close Files And Pipes-Footnote-1315219 -Ref: Close Files And Pipes-Footnote-2315367 -Node: Output Summary315517 -Node: Output Exercises316515 -Node: Expressions317195 -Node: Values318384 -Node: Constants319061 -Node: Scalar Constants319752 -Ref: Scalar Constants-Footnote-1320614 -Node: Nondecimal-numbers320864 -Node: Regexp Constants323874 -Node: Using Constant Regexps324400 -Node: Variables327563 -Node: Using Variables328220 -Node: Assignment Options330131 -Node: Conversion332006 -Node: Strings And Numbers332530 -Ref: Strings And Numbers-Footnote-1335595 -Node: Locale influences conversions335704 -Ref: table-locale-affects338450 -Node: All Operators339042 -Node: Arithmetic Ops339671 -Node: Concatenation342176 -Ref: Concatenation-Footnote-1344995 -Node: Assignment Ops345102 -Ref: table-assign-ops350081 -Node: Increment Ops351391 -Node: Truth Values and Conditions354822 -Node: Truth Values355905 -Node: Typing and Comparison356954 -Node: Variable Typing357770 -Node: Comparison Operators361437 -Ref: table-relational-ops361847 -Node: POSIX String Comparison365342 -Ref: POSIX String Comparison-Footnote-1366414 -Node: Boolean Ops366553 -Ref: Boolean Ops-Footnote-1371031 -Node: Conditional Exp371122 -Node: Function Calls372860 -Node: Precedence376740 -Node: Locales380400 -Node: Expressions Summary382032 -Node: Patterns and Actions384603 -Node: Pattern Overview385723 -Node: Regexp Patterns387402 -Node: Expression Patterns387945 -Node: Ranges391654 -Node: BEGIN/END394761 -Node: Using BEGIN/END395522 -Ref: Using BEGIN/END-Footnote-1398258 -Node: I/O And BEGIN/END398364 -Node: BEGINFILE/ENDFILE400679 -Node: Empty403576 -Node: Using Shell Variables403893 -Node: Action Overview406166 -Node: Statements408492 -Node: If Statement410340 -Node: While Statement411835 -Node: Do Statement413863 -Node: For Statement415011 -Node: Switch Statement418169 -Node: Break Statement420551 -Node: Continue Statement422592 -Node: Next Statement424419 -Node: Nextfile Statement426800 -Node: Exit Statement429428 -Node: Built-in Variables431839 -Node: User-modified432972 -Ref: User-modified-Footnote-1440675 -Node: Auto-set440737 -Ref: Auto-set-Footnote-1454446 -Ref: Auto-set-Footnote-2454651 -Node: ARGC and ARGV454707 -Node: Pattern Action Summary458925 -Node: Arrays461358 -Node: Array Basics462687 -Node: Array Intro463531 -Ref: figure-array-elements465465 -Ref: Array Intro-Footnote-1468085 -Node: Reference to Elements468213 -Node: Assigning Elements470675 -Node: Array Example471166 -Node: Scanning an Array472925 -Node: Controlling Scanning475945 -Ref: Controlling Scanning-Footnote-1481339 -Node: Numeric Array Subscripts481655 -Node: Uninitialized Subscripts483840 -Node: Delete485457 -Ref: Delete-Footnote-1488206 -Node: Multidimensional488263 -Node: Multiscanning491360 -Node: Arrays of Arrays492949 -Node: Arrays Summary497703 -Node: Functions499794 -Node: Built-in500833 -Node: Calling Built-in501911 -Node: Numeric Functions503906 -Ref: Numeric Functions-Footnote-1508724 -Ref: Numeric Functions-Footnote-2509081 -Ref: Numeric Functions-Footnote-3509129 -Node: String Functions509401 -Ref: String Functions-Footnote-1532902 -Ref: String Functions-Footnote-2533031 -Ref: String Functions-Footnote-3533279 -Node: Gory Details533366 -Ref: table-sub-escapes535147 -Ref: table-sub-proposed536662 -Ref: table-posix-sub538024 -Ref: table-gensub-escapes539561 -Ref: Gory Details-Footnote-1540394 -Node: I/O Functions540545 -Ref: I/O Functions-Footnote-1547781 -Node: Time Functions547928 -Ref: Time Functions-Footnote-1558437 -Ref: Time Functions-Footnote-2558505 -Ref: Time Functions-Footnote-3558663 -Ref: Time Functions-Footnote-4558774 -Ref: Time Functions-Footnote-5558886 -Ref: Time Functions-Footnote-6559113 -Node: Bitwise Functions559379 -Ref: table-bitwise-ops559941 -Ref: Bitwise Functions-Footnote-1564253 -Node: Type Functions564425 -Node: I18N Functions565576 -Node: User-defined567221 -Node: Definition Syntax568026 -Ref: Definition Syntax-Footnote-1573525 -Node: Function Example573596 -Ref: Function Example-Footnote-1576515 -Node: Function Caveats576537 -Node: Calling A Function577055 -Node: Variable Scope578013 -Node: Pass By Value/Reference581001 -Node: Return Statement584496 -Node: Dynamic Typing587477 -Node: Indirect Calls588406 -Ref: Indirect Calls-Footnote-1599724 -Node: Functions Summary599852 -Node: Library Functions602554 -Ref: Library Functions-Footnote-1606163 -Ref: Library Functions-Footnote-2606306 -Node: Library Names606477 -Ref: Library Names-Footnote-1609931 -Ref: Library Names-Footnote-2610154 -Node: General Functions610240 -Node: Strtonum Function611343 -Node: Assert Function614365 -Node: Round Function617689 -Node: Cliff Random Function619230 -Node: Ordinal Functions620246 -Ref: Ordinal Functions-Footnote-1623309 -Ref: Ordinal Functions-Footnote-2623561 -Node: Join Function623772 -Ref: Join Function-Footnote-1625541 -Node: Getlocaltime Function625741 -Node: Readfile Function629485 -Node: Shell Quoting631455 -Node: Data File Management632856 -Node: Filetrans Function633488 -Node: Rewind Function637544 -Node: File Checking638931 -Ref: File Checking-Footnote-1640263 -Node: Empty Files640464 -Node: Ignoring Assigns642443 -Node: Getopt Function643994 -Ref: Getopt Function-Footnote-1655456 -Node: Passwd Functions655656 -Ref: Passwd Functions-Footnote-1664493 -Node: Group Functions664581 -Ref: Group Functions-Footnote-1672475 -Node: Walking Arrays672688 -Node: Library Functions Summary674291 -Node: Library Exercises675692 -Node: Sample Programs676972 -Node: Running Examples677742 -Node: Clones678470 -Node: Cut Program679694 -Node: Egrep Program689413 -Ref: Egrep Program-Footnote-1696911 -Node: Id Program697021 -Node: Split Program700666 -Ref: Split Program-Footnote-1704114 -Node: Tee Program704242 -Node: Uniq Program707031 -Node: Wc Program714450 -Ref: Wc Program-Footnote-1718700 -Node: Miscellaneous Programs718794 -Node: Dupword Program720007 -Node: Alarm Program722038 -Node: Translate Program726842 -Ref: Translate Program-Footnote-1731407 -Node: Labels Program731677 -Ref: Labels Program-Footnote-1735028 -Node: Word Sorting735112 -Node: History Sorting739183 -Node: Extract Program741019 -Node: Simple Sed748544 -Node: Igawk Program751612 -Ref: Igawk Program-Footnote-1765936 -Ref: Igawk Program-Footnote-2766137 -Ref: Igawk Program-Footnote-3766259 -Node: Anagram Program766374 -Node: Signature Program769431 -Node: Programs Summary770678 -Node: Programs Exercises771871 -Ref: Programs Exercises-Footnote-1776002 -Node: Advanced Features776093 -Node: Nondecimal Data778041 -Node: Array Sorting779631 -Node: Controlling Array Traversal780328 -Ref: Controlling Array Traversal-Footnote-1788661 -Node: Array Sorting Functions788779 -Ref: Array Sorting Functions-Footnote-1792668 -Node: Two-way I/O792864 -Ref: Two-way I/O-Footnote-1797809 -Ref: Two-way I/O-Footnote-2797995 -Node: TCP/IP Networking798077 -Node: Profiling800950 -Node: Advanced Features Summary809227 -Node: Internationalization811160 -Node: I18N and L10N812640 -Node: Explaining gettext813326 -Ref: Explaining gettext-Footnote-1818351 -Ref: Explaining gettext-Footnote-2818535 -Node: Programmer i18n818700 -Ref: Programmer i18n-Footnote-1823566 -Node: Translator i18n823615 -Node: String Extraction824409 -Ref: String Extraction-Footnote-1825540 -Node: Printf Ordering825626 -Ref: Printf Ordering-Footnote-1828412 -Node: I18N Portability828476 -Ref: I18N Portability-Footnote-1830931 -Node: I18N Example830994 -Ref: I18N Example-Footnote-1833797 -Node: Gawk I18N833869 -Node: I18N Summary834507 -Node: Debugger835846 -Node: Debugging836868 -Node: Debugging Concepts837309 -Node: Debugging Terms839162 -Node: Awk Debugging841734 -Node: Sample Debugging Session842628 -Node: Debugger Invocation843148 -Node: Finding The Bug844532 -Node: List of Debugger Commands851007 -Node: Breakpoint Control852340 -Node: Debugger Execution Control856036 -Node: Viewing And Changing Data859400 -Node: Execution Stack862778 -Node: Debugger Info864415 -Node: Miscellaneous Debugger Commands868432 -Node: Readline Support873461 -Node: Limitations874353 -Node: Debugging Summary876467 -Node: Arbitrary Precision Arithmetic877635 -Node: Computer Arithmetic879051 -Ref: table-numeric-ranges882649 -Ref: Computer Arithmetic-Footnote-1883508 -Node: Math Definitions883565 -Ref: table-ieee-formats886853 -Ref: Math Definitions-Footnote-1887457 -Node: MPFR features887562 -Node: FP Math Caution889233 -Ref: FP Math Caution-Footnote-1890283 -Node: Inexactness of computations890652 -Node: Inexact representation891611 -Node: Comparing FP Values892968 -Node: Errors accumulate894050 -Node: Getting Accuracy895483 -Node: Try To Round898145 -Node: Setting precision899044 -Ref: table-predefined-precision-strings899728 -Node: Setting the rounding mode901517 -Ref: table-gawk-rounding-modes901881 -Ref: Setting the rounding mode-Footnote-1905336 -Node: Arbitrary Precision Integers905515 -Ref: Arbitrary Precision Integers-Footnote-1910415 -Node: POSIX Floating Point Problems910564 -Ref: POSIX Floating Point Problems-Footnote-1914437 -Node: Floating point summary914475 -Node: Dynamic Extensions916669 -Node: Extension Intro918221 -Node: Plugin License919487 -Node: Extension Mechanism Outline920284 -Ref: figure-load-extension920712 -Ref: figure-register-new-function922192 -Ref: figure-call-new-function923196 -Node: Extension API Description925182 -Node: Extension API Functions Introduction926632 -Node: General Data Types931456 -Ref: General Data Types-Footnote-1937195 -Node: Memory Allocation Functions937494 -Ref: Memory Allocation Functions-Footnote-1940333 -Node: Constructor Functions940429 -Node: Registration Functions942163 -Node: Extension Functions942848 -Node: Exit Callback Functions945145 -Node: Extension Version String946393 -Node: Input Parsers947058 -Node: Output Wrappers956937 -Node: Two-way processors961452 -Node: Printing Messages963656 -Ref: Printing Messages-Footnote-1964732 -Node: Updating `ERRNO'964884 -Node: Requesting Values965624 -Ref: table-value-types-returned966352 -Node: Accessing Parameters967309 -Node: Symbol Table Access968540 -Node: Symbol table by name969054 -Node: Symbol table by cookie971035 -Ref: Symbol table by cookie-Footnote-1975179 -Node: Cached values975242 -Ref: Cached values-Footnote-1978741 -Node: Array Manipulation978832 -Ref: Array Manipulation-Footnote-1979930 -Node: Array Data Types979967 -Ref: Array Data Types-Footnote-1982622 -Node: Array Functions982714 -Node: Flattening Arrays986568 -Node: Creating Arrays993460 -Node: Extension API Variables998231 -Node: Extension Versioning998867 -Node: Extension API Informational Variables1000768 -Node: Extension API Boilerplate1001833 -Node: Finding Extensions1005642 -Node: Extension Example1006202 -Node: Internal File Description1006974 -Node: Internal File Ops1011041 -Ref: Internal File Ops-Footnote-11022711 -Node: Using Internal File Ops1022851 -Ref: Using Internal File Ops-Footnote-11025234 -Node: Extension Samples1025507 -Node: Extension Sample File Functions1027033 -Node: Extension Sample Fnmatch1034671 -Node: Extension Sample Fork1036162 -Node: Extension Sample Inplace1037377 -Node: Extension Sample Ord1039052 -Node: Extension Sample Readdir1039888 -Ref: table-readdir-file-types1040764 -Node: Extension Sample Revout1041575 -Node: Extension Sample Rev2way1042165 -Node: Extension Sample Read write array1042905 -Node: Extension Sample Readfile1044845 -Node: Extension Sample Time1045940 -Node: Extension Sample API Tests1047289 -Node: gawkextlib1047780 -Node: Extension summary1050438 -Node: Extension Exercises1054127 -Node: Language History1054849 -Node: V7/SVR3.11056505 -Node: SVR41058686 -Node: POSIX1060131 -Node: BTL1061520 -Node: POSIX/GNU1062254 -Node: Feature History1067878 -Node: Common Extensions1080976 -Node: Ranges and Locales1082300 -Ref: Ranges and Locales-Footnote-11086918 -Ref: Ranges and Locales-Footnote-21086945 -Ref: Ranges and Locales-Footnote-31087179 -Node: Contributors1087400 -Node: History summary1092941 -Node: Installation1094311 -Node: Gawk Distribution1095257 -Node: Getting1095741 -Node: Extracting1096564 -Node: Distribution contents1098199 -Node: Unix Installation1104264 -Node: Quick Installation1104947 -Node: Shell Startup Files1107358 -Node: Additional Configuration Options1108437 -Node: Configuration Philosophy1110176 -Node: Non-Unix Installation1112545 -Node: PC Installation1113003 -Node: PC Binary Installation1114322 -Node: PC Compiling1116170 -Ref: PC Compiling-Footnote-11119191 -Node: PC Testing1119300 -Node: PC Using1120476 -Node: Cygwin1124591 -Node: MSYS1125414 -Node: VMS Installation1125914 -Node: VMS Compilation1126706 -Ref: VMS Compilation-Footnote-11127928 -Node: VMS Dynamic Extensions1127986 -Node: VMS Installation Details1129670 -Node: VMS Running1131922 -Node: VMS GNV1134758 -Node: VMS Old Gawk1135492 -Node: Bugs1135962 -Node: Other Versions1139845 -Node: Installation summary1146269 -Node: Notes1147325 -Node: Compatibility Mode1148190 -Node: Additions1148972 -Node: Accessing The Source1149897 -Node: Adding Code1151332 -Node: New Ports1157489 -Node: Derived Files1161971 -Ref: Derived Files-Footnote-11167446 -Ref: Derived Files-Footnote-21167480 -Ref: Derived Files-Footnote-31168076 -Node: Future Extensions1168190 -Node: Implementation Limitations1168796 -Node: Extension Design1170044 -Node: Old Extension Problems1171198 -Ref: Old Extension Problems-Footnote-11172715 -Node: Extension New Mechanism Goals1172772 -Ref: Extension New Mechanism Goals-Footnote-11176132 -Node: Extension Other Design Decisions1176321 -Node: Extension Future Growth1178429 -Node: Old Extension Mechanism1179265 -Node: Notes summary1181027 -Node: Basic Concepts1182213 -Node: Basic High Level1182894 -Ref: figure-general-flow1183166 -Ref: figure-process-flow1183765 -Ref: Basic High Level-Footnote-11186994 -Node: Basic Data Typing1187179 -Node: Glossary1190507 -Node: Copying1222436 -Node: GNU Free Documentation License1259992 -Node: Index1285128 +Node: Foreword342385 +Node: Foreword446829 +Node: Preface48360 +Ref: Preface-Footnote-151231 +Ref: Preface-Footnote-251338 +Ref: Preface-Footnote-351571 +Node: History51713 +Node: Names54064 +Ref: Names-Footnote-155157 +Node: This Manual55303 +Ref: This Manual-Footnote-161803 +Node: Conventions61903 +Node: Manual History64240 +Ref: Manual History-Footnote-167233 +Ref: Manual History-Footnote-267274 +Node: How To Contribute67348 +Node: Acknowledgments68477 +Node: Getting Started73294 +Node: Running gawk75733 +Node: One-shot76923 +Node: Read Terminal78187 +Node: Long80218 +Node: Executable Scripts81731 +Ref: Executable Scripts-Footnote-184520 +Node: Comments84623 +Node: Quoting87105 +Node: DOS Quoting92623 +Node: Sample Data Files93298 +Node: Very Simple95893 +Node: Two Rules100792 +Node: More Complex102678 +Node: Statements/Lines105540 +Ref: Statements/Lines-Footnote-1109995 +Node: Other Features110260 +Node: When111196 +Ref: When-Footnote-1112950 +Node: Intro Summary113015 +Node: Invoking Gawk113899 +Node: Command Line115413 +Node: Options116211 +Ref: Options-Footnote-1132006 +Ref: Options-Footnote-2132235 +Node: Other Arguments132260 +Node: Naming Standard Input135208 +Node: Environment Variables136301 +Node: AWKPATH Variable136859 +Ref: AWKPATH Variable-Footnote-1140266 +Ref: AWKPATH Variable-Footnote-2140311 +Node: AWKLIBPATH Variable140571 +Node: Other Environment Variables141827 +Node: Exit Status145345 +Node: Include Files146021 +Node: Loading Shared Libraries149610 +Node: Obsolete151037 +Node: Undocumented151729 +Node: Invoking Summary151996 +Node: Regexp153659 +Node: Regexp Usage155113 +Node: Escape Sequences157150 +Node: Regexp Operators163390 +Ref: Regexp Operators-Footnote-1170800 +Ref: Regexp Operators-Footnote-2170947 +Node: Bracket Expressions171045 +Ref: table-char-classes173060 +Node: Leftmost Longest176002 +Node: Computed Regexps177304 +Node: GNU Regexp Operators180733 +Node: Case-sensitivity184405 +Ref: Case-sensitivity-Footnote-1187290 +Ref: Case-sensitivity-Footnote-2187525 +Node: Regexp Summary187633 +Node: Reading Files189100 +Node: Records191262 +Node: awk split records191995 +Node: gawk split records196924 +Ref: gawk split records-Footnote-1201463 +Node: Fields201500 +Ref: Fields-Footnote-1204278 +Node: Nonconstant Fields204364 +Ref: Nonconstant Fields-Footnote-1206602 +Node: Changing Fields206805 +Node: Field Separators212736 +Node: Default Field Splitting215440 +Node: Regexp Field Splitting216557 +Node: Single Character Fields219907 +Node: Command Line Field Separator220966 +Node: Full Line Fields224183 +Ref: Full Line Fields-Footnote-1225704 +Ref: Full Line Fields-Footnote-2225750 +Node: Field Splitting Summary225851 +Node: Constant Size227925 +Node: Splitting By Content232508 +Ref: Splitting By Content-Footnote-1236473 +Node: Multiple Line236636 +Ref: Multiple Line-Footnote-1242517 +Node: Getline242696 +Node: Plain Getline245175 +Node: Getline/Variable247815 +Node: Getline/File248964 +Node: Getline/Variable/File250349 +Ref: Getline/Variable/File-Footnote-1251952 +Node: Getline/Pipe252039 +Node: Getline/Variable/Pipe254717 +Node: Getline/Coprocess255848 +Node: Getline/Variable/Coprocess257112 +Node: Getline Notes257851 +Node: Getline Summary260645 +Ref: table-getline-variants261057 +Node: Read Timeout261886 +Ref: Read Timeout-Footnote-1265789 +Node: Retrying Input265847 +Node: Command-line directories267042 +Node: Input Summary267949 +Node: Input Exercises271334 +Node: Printing272062 +Node: Print273839 +Node: Print Examples275296 +Node: Output Separators278075 +Node: OFMT280093 +Node: Printf281448 +Node: Basic Printf282233 +Node: Control Letters283805 +Node: Format Modifiers287790 +Node: Printf Examples293800 +Node: Redirection296286 +Node: Special FD303124 +Ref: Special FD-Footnote-1306290 +Node: Special Files306364 +Node: Other Inherited Files306981 +Node: Special Network307981 +Node: Special Caveats308843 +Node: Close Files And Pipes309792 +Ref: Close Files And Pipes-Footnote-1316983 +Ref: Close Files And Pipes-Footnote-2317131 +Node: Output Summary317281 +Node: Output Exercises318279 +Node: Expressions318959 +Node: Values320148 +Node: Constants320825 +Node: Scalar Constants321516 +Ref: Scalar Constants-Footnote-1322378 +Node: Nondecimal-numbers322628 +Node: Regexp Constants325638 +Node: Using Constant Regexps326164 +Node: Variables329327 +Node: Using Variables329984 +Node: Assignment Options331895 +Node: Conversion333770 +Node: Strings And Numbers334294 +Ref: Strings And Numbers-Footnote-1337359 +Node: Locale influences conversions337468 +Ref: table-locale-affects340214 +Node: All Operators340806 +Node: Arithmetic Ops341435 +Node: Concatenation343940 +Ref: Concatenation-Footnote-1346759 +Node: Assignment Ops346866 +Ref: table-assign-ops351845 +Node: Increment Ops353155 +Node: Truth Values and Conditions356586 +Node: Truth Values357669 +Node: Typing and Comparison358718 +Node: Variable Typing359534 +Node: Comparison Operators363201 +Ref: table-relational-ops363611 +Node: POSIX String Comparison367106 +Ref: POSIX String Comparison-Footnote-1368178 +Node: Boolean Ops368317 +Ref: Boolean Ops-Footnote-1372795 +Node: Conditional Exp372886 +Node: Function Calls374624 +Node: Precedence378504 +Node: Locales382164 +Node: Expressions Summary383796 +Node: Patterns and Actions386367 +Node: Pattern Overview387487 +Node: Regexp Patterns389166 +Node: Expression Patterns389709 +Node: Ranges393418 +Node: BEGIN/END396525 +Node: Using BEGIN/END397286 +Ref: Using BEGIN/END-Footnote-1400022 +Node: I/O And BEGIN/END400128 +Node: BEGINFILE/ENDFILE402443 +Node: Empty405340 +Node: Using Shell Variables405657 +Node: Action Overview407930 +Node: Statements410256 +Node: If Statement412104 +Node: While Statement413599 +Node: Do Statement415627 +Node: For Statement416775 +Node: Switch Statement419933 +Node: Break Statement422315 +Node: Continue Statement424356 +Node: Next Statement426183 +Node: Nextfile Statement428564 +Node: Exit Statement431192 +Node: Built-in Variables433603 +Node: User-modified434736 +Ref: User-modified-Footnote-1442439 +Node: Auto-set442501 +Ref: Auto-set-Footnote-1456734 +Ref: Auto-set-Footnote-2456939 +Node: ARGC and ARGV456995 +Node: Pattern Action Summary461213 +Node: Arrays463646 +Node: Array Basics464975 +Node: Array Intro465819 +Ref: figure-array-elements467753 +Ref: Array Intro-Footnote-1470373 +Node: Reference to Elements470501 +Node: Assigning Elements472963 +Node: Array Example473454 +Node: Scanning an Array475213 +Node: Controlling Scanning478233 +Ref: Controlling Scanning-Footnote-1483627 +Node: Numeric Array Subscripts483943 +Node: Uninitialized Subscripts486128 +Node: Delete487745 +Ref: Delete-Footnote-1490494 +Node: Multidimensional490551 +Node: Multiscanning493648 +Node: Arrays of Arrays495237 +Node: Arrays Summary499991 +Node: Functions502082 +Node: Built-in503121 +Node: Calling Built-in504199 +Node: Numeric Functions506194 +Ref: Numeric Functions-Footnote-1511012 +Ref: Numeric Functions-Footnote-2511369 +Ref: Numeric Functions-Footnote-3511417 +Node: String Functions511689 +Ref: String Functions-Footnote-1535190 +Ref: String Functions-Footnote-2535319 +Ref: String Functions-Footnote-3535567 +Node: Gory Details535654 +Ref: table-sub-escapes537435 +Ref: table-sub-proposed538950 +Ref: table-posix-sub540312 +Ref: table-gensub-escapes541849 +Ref: Gory Details-Footnote-1542682 +Node: I/O Functions542833 +Ref: I/O Functions-Footnote-1550069 +Node: Time Functions550216 +Ref: Time Functions-Footnote-1560725 +Ref: Time Functions-Footnote-2560793 +Ref: Time Functions-Footnote-3560951 +Ref: Time Functions-Footnote-4561062 +Ref: Time Functions-Footnote-5561174 +Ref: Time Functions-Footnote-6561401 +Node: Bitwise Functions561667 +Ref: table-bitwise-ops562229 +Ref: Bitwise Functions-Footnote-1566541 +Node: Type Functions566713 +Node: I18N Functions567864 +Node: User-defined569509 +Node: Definition Syntax570314 +Ref: Definition Syntax-Footnote-1575813 +Node: Function Example575884 +Ref: Function Example-Footnote-1578803 +Node: Function Caveats578825 +Node: Calling A Function579343 +Node: Variable Scope580301 +Node: Pass By Value/Reference583289 +Node: Return Statement586784 +Node: Dynamic Typing589765 +Node: Indirect Calls590694 +Ref: Indirect Calls-Footnote-1602012 +Node: Functions Summary602140 +Node: Library Functions604842 +Ref: Library Functions-Footnote-1608451 +Ref: Library Functions-Footnote-2608594 +Node: Library Names608765 +Ref: Library Names-Footnote-1612219 +Ref: Library Names-Footnote-2612442 +Node: General Functions612528 +Node: Strtonum Function613631 +Node: Assert Function616653 +Node: Round Function619977 +Node: Cliff Random Function621518 +Node: Ordinal Functions622534 +Ref: Ordinal Functions-Footnote-1625597 +Ref: Ordinal Functions-Footnote-2625849 +Node: Join Function626060 +Ref: Join Function-Footnote-1627829 +Node: Getlocaltime Function628029 +Node: Readfile Function631773 +Node: Shell Quoting633743 +Node: Data File Management635144 +Node: Filetrans Function635776 +Node: Rewind Function639832 +Node: File Checking641219 +Ref: File Checking-Footnote-1642551 +Node: Empty Files642752 +Node: Ignoring Assigns644731 +Node: Getopt Function646282 +Ref: Getopt Function-Footnote-1657744 +Node: Passwd Functions657944 +Ref: Passwd Functions-Footnote-1666781 +Node: Group Functions666869 +Ref: Group Functions-Footnote-1674763 +Node: Walking Arrays674976 +Node: Library Functions Summary676579 +Node: Library Exercises677980 +Node: Sample Programs679260 +Node: Running Examples680030 +Node: Clones680758 +Node: Cut Program681982 +Node: Egrep Program691701 +Ref: Egrep Program-Footnote-1699199 +Node: Id Program699309 +Node: Split Program702954 +Ref: Split Program-Footnote-1706402 +Node: Tee Program706530 +Node: Uniq Program709319 +Node: Wc Program716738 +Ref: Wc Program-Footnote-1720988 +Node: Miscellaneous Programs721082 +Node: Dupword Program722295 +Node: Alarm Program724326 +Node: Translate Program729130 +Ref: Translate Program-Footnote-1733695 +Node: Labels Program733965 +Ref: Labels Program-Footnote-1737316 +Node: Word Sorting737400 +Node: History Sorting741471 +Node: Extract Program743307 +Node: Simple Sed750832 +Node: Igawk Program753900 +Ref: Igawk Program-Footnote-1768224 +Ref: Igawk Program-Footnote-2768425 +Ref: Igawk Program-Footnote-3768547 +Node: Anagram Program768662 +Node: Signature Program771719 +Node: Programs Summary772966 +Node: Programs Exercises774159 +Ref: Programs Exercises-Footnote-1778290 +Node: Advanced Features778381 +Node: Nondecimal Data780329 +Node: Array Sorting781919 +Node: Controlling Array Traversal782616 +Ref: Controlling Array Traversal-Footnote-1790949 +Node: Array Sorting Functions791067 +Ref: Array Sorting Functions-Footnote-1794956 +Node: Two-way I/O795152 +Ref: Two-way I/O-Footnote-1800097 +Ref: Two-way I/O-Footnote-2800283 +Node: TCP/IP Networking800365 +Node: Profiling803238 +Node: Advanced Features Summary811515 +Node: Internationalization813448 +Node: I18N and L10N814928 +Node: Explaining gettext815614 +Ref: Explaining gettext-Footnote-1820639 +Ref: Explaining gettext-Footnote-2820823 +Node: Programmer i18n820988 +Ref: Programmer i18n-Footnote-1825854 +Node: Translator i18n825903 +Node: String Extraction826697 +Ref: String Extraction-Footnote-1827828 +Node: Printf Ordering827914 +Ref: Printf Ordering-Footnote-1830700 +Node: I18N Portability830764 +Ref: I18N Portability-Footnote-1833219 +Node: I18N Example833282 +Ref: I18N Example-Footnote-1836085 +Node: Gawk I18N836157 +Node: I18N Summary836795 +Node: Debugger838134 +Node: Debugging839156 +Node: Debugging Concepts839597 +Node: Debugging Terms841450 +Node: Awk Debugging844022 +Node: Sample Debugging Session844916 +Node: Debugger Invocation845436 +Node: Finding The Bug846820 +Node: List of Debugger Commands853295 +Node: Breakpoint Control854628 +Node: Debugger Execution Control858324 +Node: Viewing And Changing Data861688 +Node: Execution Stack865066 +Node: Debugger Info866703 +Node: Miscellaneous Debugger Commands870720 +Node: Readline Support875749 +Node: Limitations876641 +Node: Debugging Summary878755 +Node: Arbitrary Precision Arithmetic879923 +Node: Computer Arithmetic881339 +Ref: table-numeric-ranges884937 +Ref: Computer Arithmetic-Footnote-1885796 +Node: Math Definitions885853 +Ref: table-ieee-formats889141 +Ref: Math Definitions-Footnote-1889745 +Node: MPFR features889850 +Node: FP Math Caution891521 +Ref: FP Math Caution-Footnote-1892571 +Node: Inexactness of computations892940 +Node: Inexact representation893899 +Node: Comparing FP Values895256 +Node: Errors accumulate896338 +Node: Getting Accuracy897771 +Node: Try To Round900433 +Node: Setting precision901332 +Ref: table-predefined-precision-strings902016 +Node: Setting the rounding mode903805 +Ref: table-gawk-rounding-modes904169 +Ref: Setting the rounding mode-Footnote-1907624 +Node: Arbitrary Precision Integers907803 +Ref: Arbitrary Precision Integers-Footnote-1912703 +Node: POSIX Floating Point Problems912852 +Ref: POSIX Floating Point Problems-Footnote-1916725 +Node: Floating point summary916763 +Node: Dynamic Extensions918957 +Node: Extension Intro920509 +Node: Plugin License921775 +Node: Extension Mechanism Outline922572 +Ref: figure-load-extension923000 +Ref: figure-register-new-function924480 +Ref: figure-call-new-function925484 +Node: Extension API Description927470 +Node: Extension API Functions Introduction929004 +Node: General Data Types933876 +Ref: General Data Types-Footnote-1939615 +Node: Memory Allocation Functions939914 +Ref: Memory Allocation Functions-Footnote-1942753 +Node: Constructor Functions942849 +Node: Registration Functions944583 +Node: Extension Functions945268 +Node: Exit Callback Functions947565 +Node: Extension Version String948813 +Node: Input Parsers949478 +Node: Output Wrappers959357 +Node: Two-way processors963872 +Node: Printing Messages966076 +Ref: Printing Messages-Footnote-1967152 +Node: Updating `ERRNO'967304 +Node: Requesting Values968044 +Ref: table-value-types-returned968772 +Node: Accessing Parameters969729 +Node: Symbol Table Access970960 +Node: Symbol table by name971474 +Node: Symbol table by cookie973455 +Ref: Symbol table by cookie-Footnote-1977599 +Node: Cached values977662 +Ref: Cached values-Footnote-1981161 +Node: Array Manipulation981252 +Ref: Array Manipulation-Footnote-1982342 +Node: Array Data Types982379 +Ref: Array Data Types-Footnote-1985034 +Node: Array Functions985126 +Node: Flattening Arrays988980 +Node: Creating Arrays995872 +Node: Redirection API1000643 +Node: Extension API Variables1003414 +Node: Extension Versioning1004047 +Node: Extension API Informational Variables1005948 +Node: Extension API Boilerplate1007013 +Node: Finding Extensions1010822 +Node: Extension Example1011382 +Node: Internal File Description1012154 +Node: Internal File Ops1016221 +Ref: Internal File Ops-Footnote-11027891 +Node: Using Internal File Ops1028031 +Ref: Using Internal File Ops-Footnote-11030414 +Node: Extension Samples1030687 +Node: Extension Sample File Functions1032213 +Node: Extension Sample Fnmatch1039851 +Node: Extension Sample Fork1041342 +Node: Extension Sample Inplace1042557 +Node: Extension Sample Ord1044232 +Node: Extension Sample Readdir1045068 +Ref: table-readdir-file-types1045944 +Node: Extension Sample Revout1046755 +Node: Extension Sample Rev2way1047345 +Node: Extension Sample Read write array1048085 +Node: Extension Sample Readfile1050025 +Node: Extension Sample Time1051120 +Node: Extension Sample API Tests1052469 +Node: gawkextlib1052960 +Node: Extension summary1055618 +Node: Extension Exercises1059307 +Node: Language History1060029 +Node: V7/SVR3.11061685 +Node: SVR41063866 +Node: POSIX1065311 +Node: BTL1066700 +Node: POSIX/GNU1067434 +Node: Feature History1073058 +Node: Common Extensions1086156 +Node: Ranges and Locales1087480 +Ref: Ranges and Locales-Footnote-11092098 +Ref: Ranges and Locales-Footnote-21092125 +Ref: Ranges and Locales-Footnote-31092359 +Node: Contributors1092580 +Node: History summary1098121 +Node: Installation1099491 +Node: Gawk Distribution1100437 +Node: Getting1100921 +Node: Extracting1101744 +Node: Distribution contents1103379 +Node: Unix Installation1109444 +Node: Quick Installation1110127 +Node: Shell Startup Files1112538 +Node: Additional Configuration Options1113617 +Node: Configuration Philosophy1115356 +Node: Non-Unix Installation1117725 +Node: PC Installation1118183 +Node: PC Binary Installation1119502 +Node: PC Compiling1121350 +Ref: PC Compiling-Footnote-11124371 +Node: PC Testing1124480 +Node: PC Using1125656 +Node: Cygwin1129771 +Node: MSYS1130594 +Node: VMS Installation1131094 +Node: VMS Compilation1131886 +Ref: VMS Compilation-Footnote-11133108 +Node: VMS Dynamic Extensions1133166 +Node: VMS Installation Details1134850 +Node: VMS Running1137102 +Node: VMS GNV1139938 +Node: VMS Old Gawk1140672 +Node: Bugs1141142 +Node: Other Versions1145025 +Node: Installation summary1151449 +Node: Notes1152505 +Node: Compatibility Mode1153370 +Node: Additions1154152 +Node: Accessing The Source1155077 +Node: Adding Code1156512 +Node: New Ports1162669 +Node: Derived Files1167151 +Ref: Derived Files-Footnote-11172626 +Ref: Derived Files-Footnote-21172660 +Ref: Derived Files-Footnote-31173256 +Node: Future Extensions1173370 +Node: Implementation Limitations1173976 +Node: Extension Design1175224 +Node: Old Extension Problems1176378 +Ref: Old Extension Problems-Footnote-11177895 +Node: Extension New Mechanism Goals1177952 +Ref: Extension New Mechanism Goals-Footnote-11181312 +Node: Extension Other Design Decisions1181501 +Node: Extension Future Growth1183609 +Node: Old Extension Mechanism1184445 +Node: Notes summary1186207 +Node: Basic Concepts1187393 +Node: Basic High Level1188074 +Ref: figure-general-flow1188346 +Ref: figure-process-flow1188945 +Ref: Basic High Level-Footnote-11192174 +Node: Basic Data Typing1192359 +Node: Glossary1195687 +Node: Copying1227616 +Node: GNU Free Documentation License1265172 +Node: Index1290308 End Tag Table diff --git a/doc/gawk.texi b/doc/gawk.texi index 68512c2d..9ad9e3d4 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -603,6 +603,7 @@ 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. @@ -943,6 +944,7 @@ 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 @@ -6318,6 +6320,7 @@ 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. @@ -8103,6 +8106,11 @@ it encounters the end of the file. If there is some error in getting 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 the @code{errno} variable indicates that the I/O operation may be +retried, and @code{PROCINFO["input", "RETRY"]} is set, then @minus{}2 +will be returned 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. @@ -8758,7 +8766,8 @@ 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 @@ -8768,6 +8777,35 @@ 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, it will by default +return @minus{}1 from getline, and subsequent attempts to read from that file +will 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 setting a special element +in the @code{PROCINFO} array (@pxref{Auto-set}): + +@example +PROCINFO["input_name", "RETRY"] +@end example + +When set, this causes @command{gawk} to check the value of the system +@code{errno} variable when an I/O error occurs. If @code{errno} indicates +a subsequent I/O attempt may succeed, @code{getline} will instead return +@minus{}2 and +further calls to @code{getline} may succeed. This applies to @code{errno} +values EAGAIN, EWOULDBLOCK, EINTR, or ETIMEDOUT. + +This feature is useful in conjunction with +@code{PROCINFO["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 @@ -14841,6 +14879,11 @@ 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} @@ -14909,6 +14952,10 @@ 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. @@ -15048,6 +15095,11 @@ 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}. @@ -31461,6 +31513,7 @@ 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 @@ -31536,6 +31589,10 @@ 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: @@ -33500,6 +33557,62 @@ $ @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 NULL or @code{name_len} is 0, it returns +data for the currently open input file corresponding to @code{FILENAME} +(and it will not access the @code{filetype} argument, so that may be +undefined). +If the file is not already open, it tries to open it. +The @code{filetype} argument must be NUL-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, a @code{false} value is returned. Otherwise, the return status +is @code{true}, and additional information about the redirection is +returned in the @code{ibufp} and @code{obufp} pointers. For input redirections, +the @code{*ibufp} value should be non-NULL, and @code{*obufp} should be NULL. +For output redirections, +the @code{*obufp} value should be non-NULL, and @code{*ibufp} should be NULL. +For two-way coprocesses, both values should be non-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 fd argument is non-negative, +@command{gawk} will use that file descriptor instead of opening the file +in the usual way. If the fd is non-negative, but the file exists +already, @command{gawk} ignores the fd and returns the existing file. It is +the caller's responsibility to notice that neither the fd in the returned +@code{awk_input_buf_t} nor the fd in the returned @code{awk_output_buf_t} matches the requested value. Note that +supplying a file descriptor is currently NOT supported for pipes. +It should work for input, output, append, and two-way (coprocess) +sockets. If @code{filetype} is two-way, we assume that it is a socket! +Note that in the two-way case, the input and output file descriptors +may differ. To check for success, one 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 diff --git a/doc/gawktexi.in b/doc/gawktexi.in index f3805887..e557efae 100644 --- a/doc/gawktexi.in +++ b/doc/gawktexi.in @@ -598,6 +598,7 @@ 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. @@ -938,6 +939,7 @@ 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 @@ -6102,6 +6104,7 @@ 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. @@ -7703,6 +7706,11 @@ it encounters the end of the file. If there is some error in getting 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 the @code{errno} variable indicates that the I/O operation may be +retried, and @code{PROCINFO["input", "RETRY"]} is set, then @minus{}2 +will be returned 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. @@ -8358,7 +8366,8 @@ 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 @@ -8368,6 +8377,35 @@ 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, it will by default +return @minus{}1 from getline, and subsequent attempts to read from that file +will 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 setting a special element +in the @code{PROCINFO} array (@pxref{Auto-set}): + +@example +PROCINFO["input_name", "RETRY"] +@end example + +When set, this causes @command{gawk} to check the value of the system +@code{errno} variable when an I/O error occurs. If @code{errno} indicates +a subsequent I/O attempt may succeed, @code{getline} will instead return +@minus{}2 and +further calls to @code{getline} may succeed. This applies to @code{errno} +values EAGAIN, EWOULDBLOCK, EINTR, or ETIMEDOUT. + +This feature is useful in conjunction with +@code{PROCINFO["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 @@ -14169,6 +14207,11 @@ 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} @@ -14237,6 +14280,10 @@ 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. @@ -14376,6 +14423,11 @@ 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}. @@ -30553,6 +30605,7 @@ 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 @@ -30628,6 +30681,10 @@ 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: @@ -32592,6 +32649,62 @@ $ @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 NULL or @code{name_len} is 0, it returns +data for the currently open input file corresponding to @code{FILENAME} +(and it will not access the @code{filetype} argument, so that may be +undefined). +If the file is not already open, it tries to open it. +The @code{filetype} argument must be NUL-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, a @code{false} value is returned. Otherwise, the return status +is @code{true}, and additional information about the redirection is +returned in the @code{ibufp} and @code{obufp} pointers. For input redirections, +the @code{*ibufp} value should be non-NULL, and @code{*obufp} should be NULL. +For output redirections, +the @code{*obufp} value should be non-NULL, and @code{*ibufp} should be NULL. +For two-way coprocesses, both values should be non-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 fd argument is non-negative, +@command{gawk} will use that file descriptor instead of opening the file +in the usual way. If the fd is non-negative, but the file exists +already, @command{gawk} ignores the fd and returns the existing file. It is +the caller's responsibility to notice that neither the fd in the returned +@code{awk_input_buf_t} nor the fd in the returned @code{awk_output_buf_t} matches the requested value. Note that +supplying a file descriptor is currently NOT supported for pipes. +It should work for input, output, append, and two-way (coprocess) +sockets. If @code{filetype} is two-way, we assume that it is a socket! +Note that in the two-way case, the input and output file descriptors +may differ. To check for success, one 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 |