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Diffstat (limited to 'doc/gawk.texi')
| -rw-r--r-- | doc/gawk.texi | 64 |
1 files changed, 40 insertions, 24 deletions
diff --git a/doc/gawk.texi b/doc/gawk.texi index 2d68b9cc..c8a0db6b 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -3229,9 +3229,9 @@ care to search for all occurrences of each inappropriate construct. As @command{awk} programs are usually short, doing so is not burdensome. @item -M -@itemx --bcmath +@itemx --arbitrary-precision @cindex @code{-M} option -@cindex @code{--bcmath} option +@cindex @code{--arbitrary-precision} option Force arbitrary precision arithmetic on numbers. This option has no effect if @command{gawk} is not compiled to use the GNU MPFR and MP libraries (@pxref{Arbitrary Precision Arithmetic}). @@ -12624,6 +12624,17 @@ This is the output record separator. It is output at the end of every @code{print} statement. Its default value is @code{"\n"}, the newline character. (@xref{Output Separators}.) +@cindex @code{PREC} variable +@item PREC # +The working precision of arbitrary precision floating-point numbers, +53 by default. (@xref{Setting Precision}.) + +@cindex @code{RNDMODE} variable +@item RNDMODE # +The rounding mode to use for arbitrary precision arithmetic on +numbers, by default @code{"N"} (@samp{roundTiesToEven} in IEEE-754 standard). +(@xref{Setting Rounding Mode}.) + @cindex @code{RS} variable @cindex separators, for records @cindex record separators @@ -12907,6 +12918,25 @@ The value of the @code{getuid()} system call. The version of @command{gawk}. @end table +The following additional elements in the array +are available to provide information about the MPFR and GMP libraries +if your version of @command{gawk} supports arbitrary precision numbers +(@pxref{Arbitrary Precision Arithmetic}): + +@table @code +@item PROCINFO["mpfr_version"] +The version of the GNU MPFR library. + +@item PROCINFO["gmp_version"] +The version of the GNU MP library. + +@item PROCINFO["prec_max"] +The maximum precision supported by MPFR. + +@item PROCINFO["prec_min"] +The minimum precision required by MPFR. +@end table + On some systems, there may be elements in the array, @code{"group1"} through @code{"group@var{N}"} for some @var{N}. @var{N} is the number of supplementary groups that the process has. Use the @code{in} operator @@ -18380,7 +18410,7 @@ in general, and the limitations of doing arithmetic with ordinary * Changing Precision:: Changing the Precision of a Number. * Exact Arithmetic:: Exact Arithmetic with Floating-point Numbers. * Integer Programming:: Effective Integer Programming. -* Arbitrary Precision Integers:: Arbitrary Precision Integer. +* Arbitrary Precision Integers:: Arbitrary Precision Integer Arithmetic with @command{gawk}. * MPFR and GMP Libraries:: Information About the MPFR and GMP Libraries. @end menu @@ -18535,7 +18565,7 @@ Precision of the floating-point format in bits. Maximum exponent allowed for this format. @item emin Minimum exponent allowed for this format. -@item subnormal behavior +@item underflow behavior The format may or may not support gradual underflow. @item rounding The rounding mode of this context. @@ -18675,7 +18705,7 @@ when you change the rounding mode. Gawk uses the GNU MPFR library for arbitrary precision floating-point arithmetic. The MPFR library provides precise control over precisions and rounding modes, and gives correctly rounded reproducible platform-independent results. -With the command-line option @option{--bcmath} or @option{-M}, all floating-point +With the command-line option @option{--arbitrary-precision} or @option{-M}, all floating-point arithmetic operators and numeric functions can yield results to any desired precision level supported by MPFR. Two built-in variables @code{PREC} (@pxref{Setting Precision}) @@ -18872,7 +18902,7 @@ no easy answers. The standard rules of algebra often do not apply when using floating-point arithmetic. Among other things, the distributive and associative laws do not hold completely, and order of operation may be important -for your computation. Rounding error, cumulative precision loss, +for your computation. Rounding error, cumulative precision loss and underflow are often troublesome. When @command{gawk} tests the expressions 0.1 + 12.2 and 12.3 for equality @@ -18964,7 +18994,7 @@ your terminal screen. @section Arbitrary Precision Integer Arithmetic with @command{gawk} @cindex integer, arbitrary precision -If the option @option{--bcmath} or @option{-M} is specified, @command{gawk} will perform all +If the option @option{--arbitrary-precision} or @option{-M} is specified, @command{gawk} will perform all integer arithmetic using GMP arbitrary precision integers. Any number that looks like an integer in a program source or data file will be stored as an arbitrary precision integer. @@ -19040,24 +19070,10 @@ $ @kbd{gawk -M 'BEGIN @{ n = 13; print n % 2 @}'} @node MPFR and GMP Libraries @section Information About the MPFR and GMP Libraries -@cindex @code{PROCINFO} array -The following elements of the PROCINFO array (@pxref{Built-in Variables}) -are available to provide information about the MPFR and GMP libraries: - -@table @code -@item PROCINFO["mpfr_version"] -The version of the GNU MPFR library. - -@item PROCINFO["gmp_version"] -The version of the GNU MP library. - -@item PROCINFO["prec_max"] -The maximum precision supported by MPFR. - -@item PROCINFO["prec_min"] -The minimum precision required by MPFR. -@end table +There are few elements available in the @code{PROCINFO} array +to provide information about the MPFR and GMP libraries. +(@xref{Auto-set}.) @node Advanced Features |