1 # strerror.m4 serial 16
2 dnl Copyright (C) 2002, 2007-2011 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.
7 AC_DEFUN([gl_FUNC_STRERROR],
9 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
10 AC_REQUIRE([gl_HEADER_ERRNO_H])
11 AC_REQUIRE([gl_FUNC_STRERROR_0])
12 m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
13 AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
15 if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
16 AC_CACHE_CHECK([for working strerror function],
17 [gl_cv_func_working_strerror],
22 [[if (!*strerror (-2)) return 1;]])],
23 [gl_cv_func_working_strerror=yes],
24 [gl_cv_func_working_strerror=no],
25 [dnl Be pessimistic on cross-compiles for now.
26 gl_cv_func_working_strerror="guessing no"])
28 if test "$gl_cv_func_working_strerror" != yes; then
29 dnl The system's strerror() fails to return a string for out-of-range
30 dnl integers. Replace it.
33 m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
34 dnl If the system's strerror_r or __xpg_strerror_r clobbers strerror's
35 dnl buffer, we must replace strerror.
36 case "$gl_cv_func_strerror_r_works" in
37 *no) REPLACE_STRERROR=1 ;;
41 dnl The system's strerror() cannot know about the new errno values we add
42 dnl to <errno.h>, or any fix for strerror(0). Replace it.
47 dnl Detect if strerror(0) passes (that is, does not set errno, and does not
48 dnl return a string that matches strerror(-1)).
49 AC_DEFUN([gl_FUNC_STRERROR_0],
52 AC_CACHE_CHECK([whether strerror(0) succeeds],
53 [gl_cv_func_strerror_0_works],
63 if (!*str) result |= 1;
64 if (errno) result |= 2;
65 if (strstr (str, "nknown") || strstr (str, "ndefined"))
68 [gl_cv_func_strerror_0_works=yes],
69 [gl_cv_func_strerror_0_works=no],
70 [dnl Be pessimistic on cross-compiles for now.
71 gl_cv_func_strerror_0_works="guessing no"])
73 if test "$gl_cv_func_strerror_0_works" != yes; then
75 AC_DEFINE([REPLACE_STRERROR_0], [1], [Define to 1 if strerror(0)
76 does not return a message implying success.])