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emacs/m4/setenv.m4
Paul Eggert 5badc81c1c Update copyright year to 2017
Run admin/update-copyright.
2016-12-31 19:42:26 -08:00

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# setenv.m4 serial 26
dnl Copyright (C) 2001-2004, 2006-2017 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_SETENV],
[
AC_REQUIRE([gl_FUNC_SETENV_SEPARATE])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
if test $ac_cv_func_setenv = no; then
HAVE_SETENV=0
else
AC_CACHE_CHECK([whether setenv validates arguments],
[gl_cv_func_setenv_works],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <stdlib.h>
#include <errno.h>
#include <string.h>
]], [[
int result = 0;
{
if (setenv ("", "", 0) != -1)
result |= 1;
else if (errno != EINVAL)
result |= 2;
}
{
if (setenv ("a", "=", 1) != 0)
result |= 4;
else if (strcmp (getenv ("a"), "=") != 0)
result |= 8;
}
return result;
]])],
[gl_cv_func_setenv_works=yes], [gl_cv_func_setenv_works=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu*) gl_cv_func_setenv_works="guessing yes" ;;
# If we don't know, assume the worst.
*) gl_cv_func_setenv_works="guessing no" ;;
esac
])])
case "$gl_cv_func_setenv_works" in
*yes) ;;
*)
REPLACE_SETENV=1
;;
esac
fi
])
# Like gl_FUNC_SETENV, except prepare for separate compilation
# (no REPLACE_SETENV, no AC_LIBOBJ).
AC_DEFUN([gl_FUNC_SETENV_SEPARATE],
[
AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
AC_CHECK_DECLS_ONCE([setenv])
if test $ac_cv_have_decl_setenv = no; then
HAVE_DECL_SETENV=0
fi
AC_CHECK_FUNCS_ONCE([setenv])
gl_PREREQ_SETENV
])
AC_DEFUN([gl_FUNC_UNSETENV],
[
AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_DECLS_ONCE([unsetenv])
if test $ac_cv_have_decl_unsetenv = no; then
HAVE_DECL_UNSETENV=0
fi
AC_CHECK_FUNCS([unsetenv])
if test $ac_cv_func_unsetenv = no; then
HAVE_UNSETENV=0
else
HAVE_UNSETENV=1
dnl Some BSDs return void, failing to do error checking.
AC_CACHE_CHECK([for unsetenv() return type], [gt_cv_func_unsetenv_ret],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[
#undef _BSD
#define _BSD 1 /* unhide unsetenv declaration in OSF/1 5.1 <stdlib.h> */
#include <stdlib.h>
extern
#ifdef __cplusplus
"C"
#endif
int unsetenv (const char *name);
]],
[[]])],
[gt_cv_func_unsetenv_ret='int'],
[gt_cv_func_unsetenv_ret='void'])])
if test $gt_cv_func_unsetenv_ret = 'void'; then
AC_DEFINE([VOID_UNSETENV], [1], [Define to 1 if unsetenv returns void
instead of int.])
REPLACE_UNSETENV=1
fi
dnl Solaris 10 unsetenv does not remove all copies of a name.
dnl Haiku alpha 2 unsetenv gets confused by assignment to environ.
dnl OpenBSD 4.7 unsetenv("") does not fail.
AC_CACHE_CHECK([whether unsetenv obeys POSIX],
[gl_cv_func_unsetenv_works],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <stdlib.h>
#include <errno.h>
extern char **environ;
]], [[
char entry1[] = "a=1";
char entry2[] = "b=2";
char *env[] = { entry1, entry2, NULL };
if (putenv ((char *) "a=1")) return 1;
if (putenv (entry2)) return 2;
entry2[0] = 'a';
unsetenv ("a");
if (getenv ("a")) return 3;
if (!unsetenv ("") || errno != EINVAL) return 4;
entry2[0] = 'b';
environ = env;
if (!getenv ("a")) return 5;
entry2[0] = 'a';
unsetenv ("a");
if (getenv ("a")) return 6;
]])],
[gl_cv_func_unsetenv_works=yes], [gl_cv_func_unsetenv_works=no],
[case "$host_os" in
# Guess yes on glibc systems.
*-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
# If we don't know, assume the worst.
*) gl_cv_func_unsetenv_works="guessing no" ;;
esac
])])
case "$gl_cv_func_unsetenv_works" in
*yes) ;;
*)
REPLACE_UNSETENV=1
;;
esac
fi
])
# Prerequisites of lib/setenv.c.
AC_DEFUN([gl_PREREQ_SETENV],
[
AC_REQUIRE([AC_FUNC_ALLOCA])
AC_REQUIRE([gl_ENVIRON])
AC_CHECK_HEADERS_ONCE([unistd.h])
AC_CHECK_HEADERS([search.h])
AC_CHECK_FUNCS([tsearch])
])
# Prerequisites of lib/unsetenv.c.
AC_DEFUN([gl_PREREQ_UNSETENV],
[
AC_REQUIRE([gl_ENVIRON])
AC_CHECK_HEADERS_ONCE([unistd.h])
])