gnulib/import/m4/malloc.m4

   1 # malloc.m4 serial 21
   2 dnl Copyright (C) 2007, 2009-2021 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_MALLOC_IF],
  10 [
  11   AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
  12   AC_CACHE_CHECK([for GNU libc compatible malloc],
  13     [ac_cv_func_malloc_0_nonnull],
  14     [AC_RUN_IFELSE(
  15        [AC_LANG_PROGRAM(
  16           [[#include <stdlib.h>
  17           ]],
  18           [[char *p = malloc (0);
  19             int result = !p;
  20             free (p);
  21             return result;]])
  22        ],
  23        [ac_cv_func_malloc_0_nonnull=yes],
  24        [ac_cv_func_malloc_0_nonnull=no],
  25        [case "$host_os" in
  26           # Guess yes on platforms where we know the result.
  27           *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
  28           | hpux* | solaris* | cygwin* | mingw*)
  29             ac_cv_func_malloc_0_nonnull="guessing yes" ;;
  30           # If we don't know, obey --enable-cross-guesses.
  31           *) ac_cv_func_malloc_0_nonnull="$gl_cross_guess_normal" ;;
  32         esac
  33        ])
  34     ])
  35   case "$ac_cv_func_malloc_0_nonnull" in
  36     *yes)
  37       $1
  38       ;;
  39     *)
  40       $2
  41       ;;
  42   esac
  43 ])# _AC_FUNC_MALLOC_IF
  44
  45 # gl_FUNC_MALLOC_GNU
  46 # ------------------
  47 # Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
  48 # it is not.
  49 AC_DEFUN([gl_FUNC_MALLOC_GNU],
  50 [
  51   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
  52   dnl _AC_FUNC_MALLOC_IF is defined in Autoconf.
  53   _AC_FUNC_MALLOC_IF(
  54     [AC_DEFINE([HAVE_MALLOC_GNU], [1],
  55                [Define to 1 if your system has a GNU libc compatible 'malloc'
  56                 function, and to 0 otherwise.])],
  57     [AC_DEFINE([HAVE_MALLOC_GNU], [0])
  58      REPLACE_MALLOC=1
  59     ])
  60 ])
  61
  62 # gl_FUNC_MALLOC_POSIX
  63 # --------------------
  64 # Test whether 'malloc' is POSIX compliant (sets errno to ENOMEM when it
  65 # fails), and replace malloc if it is not.
  66 AC_DEFUN([gl_FUNC_MALLOC_POSIX],
  67 [
  68   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
  69   AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
  70   if test $gl_cv_func_malloc_posix = yes; then
  71     AC_DEFINE([HAVE_MALLOC_POSIX], [1],
  72       [Define if the 'malloc' function is POSIX compliant.])
  73   else
  74     REPLACE_MALLOC=1
  75   fi
  76 ])
  77
  78 # Test whether malloc, realloc, calloc are POSIX compliant,
  79 # Set gl_cv_func_malloc_posix to yes or no accordingly.
  80 AC_DEFUN([gl_CHECK_MALLOC_POSIX],
  81 [
  82   AC_CACHE_CHECK([whether malloc, realloc, calloc are POSIX compliant],
  83     [gl_cv_func_malloc_posix],
  84     [
  85       dnl It is too dangerous to try to allocate a large amount of memory:
  86       dnl some systems go to their knees when you do that. So assume that
  87       dnl all Unix implementations of the function are POSIX compliant.
  88       AC_COMPILE_IFELSE(
  89         [AC_LANG_PROGRAM(
  90            [[]],
  91            [[#if defined _WIN32 && ! defined __CYGWIN__
  92              choke me
  93              #endif
  94             ]])],
  95         [gl_cv_func_malloc_posix=yes],
  96         [gl_cv_func_malloc_posix=no])
  97     ])
  98 ])