gnulib/import/m4/realloc.m4

   1 # realloc.m4 serial 18
   2 dnl Copyright (C) 2007, 2009-2019 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 # This is adapted with modifications from upstream Autoconf here:
   8 # https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c
   9 AC_DEFUN([_AC_FUNC_REALLOC_IF],
  10 [
  11   AC_REQUIRE([AC_HEADER_STDC])dnl
  12   AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
  13   AC_CHECK_HEADERS([stdlib.h])
  14   AC_CACHE_CHECK([for GNU libc compatible realloc],
  15     [ac_cv_func_realloc_0_nonnull],
  16     [AC_RUN_IFELSE(
  17        [AC_LANG_PROGRAM(
  18           [[#if defined STDC_HEADERS || defined HAVE_STDLIB_H
  19             # include <stdlib.h>
  20             #else
  21             char *realloc ();
  22             #endif
  23           ]],
  24           [[char *p = realloc (0, 0);
  25             int result = !p;
  26             free (p);
  27             return result;]])
  28        ],
  29        [ac_cv_func_realloc_0_nonnull=yes],
  30        [ac_cv_func_realloc_0_nonnull=no],
  31        [case "$host_os" in
  32           # Guess yes on platforms where we know the result.
  33           *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
  34           | hpux* | solaris* | cygwin* | mingw*)
  35             ac_cv_func_realloc_0_nonnull="guessing yes" ;;
  36           # If we don't know, obey --enable-cross-guesses.
  37           *) ac_cv_func_realloc_0_nonnull="$gl_cross_guess_normal" ;;
  38         esac
  39        ])
  40     ])
  41   case "$ac_cv_func_realloc_0_nonnull" in
  42     *yes)
  43       $1
  44       ;;
  45     *)
  46       $2
  47       ;;
  48   esac
  49 ])# AC_FUNC_REALLOC
  50
  51 # gl_FUNC_REALLOC_GNU
  52 # -------------------
  53 # Test whether 'realloc (0, 0)' is handled like in GNU libc, and replace
  54 # realloc if it is not.
  55 AC_DEFUN([gl_FUNC_REALLOC_GNU],
  56 [
  57   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
  58   dnl _AC_FUNC_REALLOC_IF is defined in Autoconf.
  59   _AC_FUNC_REALLOC_IF(
  60     [AC_DEFINE([HAVE_REALLOC_GNU], [1],
  61                [Define to 1 if your system has a GNU libc compatible 'realloc'
  62                 function, and to 0 otherwise.])],
  63     [AC_DEFINE([HAVE_REALLOC_GNU], [0])
  64      REPLACE_REALLOC=1
  65     ])
  66 ])# gl_FUNC_REALLOC_GNU
  67
  68 # gl_FUNC_REALLOC_POSIX
  69 # ---------------------
  70 # Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it
  71 # fails), and replace realloc if it is not.
  72 AC_DEFUN([gl_FUNC_REALLOC_POSIX],
  73 [
  74   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
  75   AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
  76   if test $gl_cv_func_malloc_posix = yes; then
  77     AC_DEFINE([HAVE_REALLOC_POSIX], [1],
  78       [Define if the 'realloc' function is POSIX compliant.])
  79   else
  80     REPLACE_REALLOC=1
  81   fi
  82 ])