# realloc.m4 serial 18

dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

# This is adapted with modifications from upstream Autoconf here:

# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c

AC_DEFUN([_AC_FUNC_REALLOC_IF],

[

  AC_REQUIRE([AC_HEADER_STDC])dnl

  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles

  AC_CHECK_HEADERS([stdlib.h])

  AC_CACHE_CHECK([for GNU libc compatible realloc],

    [ac_cv_func_realloc_0_nonnull],

    [AC_RUN_IFELSE(

       [AC_LANG_PROGRAM(

          [[#if defined STDC_HEADERS || defined HAVE_STDLIB_H

            # include <stdlib.h>

            #else

            char *realloc ();

            #endif

          ]],

          [[char *p = realloc (0, 0);

            int result = !p;

            free (p);

            return result;]])

       ],

       [ac_cv_func_realloc_0_nonnull=yes],

       [ac_cv_func_realloc_0_nonnull=no],

       [case "$host_os" in

          # Guess yes on platforms where we know the result.

          *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \

          | hpux* | solaris* | cygwin* | mingw*)

            ac_cv_func_realloc_0_nonnull="guessing yes" ;;

          # If we don't know, obey --enable-cross-guesses.

          *) ac_cv_func_realloc_0_nonnull="$gl_cross_guess_normal" ;;

        esac

       ])

    ])

  case "$ac_cv_func_realloc_0_nonnull" in

    *yes)

      $1

      ;;

    *)

      $2

      ;;

  esac

])# AC_FUNC_REALLOC

# gl_FUNC_REALLOC_GNU

# -------------------

# Test whether 'realloc (0, 0)' is handled like in GNU libc, and replace

# realloc if it is not.

AC_DEFUN([gl_FUNC_REALLOC_GNU],

[

  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])

  dnl _AC_FUNC_REALLOC_IF is defined in Autoconf.

  _AC_FUNC_REALLOC_IF(

    [AC_DEFINE([HAVE_REALLOC_GNU], [1],

               [Define to 1 if your system has a GNU libc compatible 'realloc'

                function, and to 0 otherwise.])],

    [AC_DEFINE([HAVE_REALLOC_GNU], [0])

     REPLACE_REALLOC=1

    ])

])# gl_FUNC_REALLOC_GNU

# gl_FUNC_REALLOC_POSIX

# ---------------------

# Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it

# fails), and replace realloc if it is not.

AC_DEFUN([gl_FUNC_REALLOC_POSIX],

[

  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])

  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])

  if test $gl_cv_func_malloc_posix = yes; then

    AC_DEFINE([HAVE_REALLOC_POSIX], [1],

      [Define if the 'realloc' function is POSIX compliant.])

  else

    REPLACE_REALLOC=1

  fi

])