wget/m4/strndup.m4

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# strndup.m4 serial 22
dnl Copyright (C) 2002-2003, 2005-2019 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.
AC_DEFUN([gl_FUNC_STRNDUP],
[
dnl Persuade glibc <string.h> to declare strndup().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
AC_CHECK_DECLS_ONCE([strndup])
AC_CHECK_FUNCS_ONCE([strndup])
if test $ac_cv_have_decl_strndup = no; then
HAVE_DECL_STRNDUP=0
fi
if test $ac_cv_func_strndup = yes; then
HAVE_STRNDUP=1
# AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
[AC_RUN_IFELSE([
AC_LANG_PROGRAM([[#include <string.h>
#include <stdlib.h>]], [[
#if !HAVE_DECL_STRNDUP
extern
#ifdef __cplusplus
"C"
#endif
char *strndup (const char *, size_t);
#endif
int result;
char *s;
s = strndup ("some longer string", 15);
free (s);
s = strndup ("shorter string", 13);
result = s[13] != '\0';
free (s);
return result;]])],
[gl_cv_func_strndup_works=yes],
[gl_cv_func_strndup_works=no],
[
changequote(,)dnl
case $host_os in
aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
*) gl_cv_func_strndup_works="guessing yes";;
esac
changequote([,])dnl
])])
case $gl_cv_func_strndup_works in
*no) REPLACE_STRNDUP=1 ;;
esac
else
HAVE_STRNDUP=0
fi
])