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emacs/m4/ssize_t.m4
2023-06-07 12:04:00 -07:00

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# ssize_t.m4 serial 6
dnl Copyright (C) 2001-2003, 2006, 2010-2023 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.
dnl From Bruno Haible.
dnl Define ssize_t if it does not already exist.
AC_DEFUN([gt_TYPE_SSIZE_T],
[
AC_CACHE_CHECK([for ssize_t], [gl_cv_ssize_t],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>]],
[[int x = sizeof (ssize_t *) + sizeof (ssize_t);
return !x;]])],
[gl_cv_ssize_t=yes], [gl_cv_ssize_t=no])])
if test $gl_cv_ssize_t = no; then
dnl On 64-bit native Windows, ssize_t needs to be defined as 'long long',
dnl for consistency with the 64-bit size_t.
AC_CACHE_CHECK([whether size_t is wider than 'long'], [gl_cv_size_t_large],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>
typedef int array [2 * (sizeof (size_t) > sizeof (long)) - 1];
]])],
[gl_cv_size_t_large=yes], [gl_cv_size_t_large=no])])
if test $gl_cv_size_t_large = yes; then
gl_def_ssize_t='long long'
else
gl_def_ssize_t='long'
fi
AC_DEFINE_UNQUOTED([ssize_t], [$gl_def_ssize_t],
[Define as a signed type of the same size as size_t.])
fi
])