isblank: Move AC_LIBOBJ invocations to module description.

[gnulib.git] / m4 / strerror.m4

diff --git a/m4/strerror.m4 b/m4/strerror.m4
index 52f3e3f..03a0b1a 100644 (file)
--- a/m4/strerror.m4
+++ b/m4/strerror.m4
@@ -1,49 +1,54 @@
-# strerror.m4 serial 4
-dnl Copyright (C) 2002, 2007 Free Software Foundation, Inc.
+# strerror.m4 serial 15
+dnl Copyright (C) 2002, 2007-2011 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_STRERROR],
 [
-  AC_REQUIRE([gl_FUNC_STRERROR_SEPARATE])
-  if test $gl_cv_func_working_strerror = no; then
-    AC_LIBOBJ([strerror])
-    AC_DEFINE_UNQUOTED([REPLACE_STRERROR], [$REPLACE_STRERROR],
-      [Define this to 1 if strerror is broken.])
-  fi
-])
-
-# Like gl_FUNC_STRERROR, except prepare for separate compilation (no AC_LIBOBJ).
-AC_DEFUN([gl_FUNC_STRERROR_SEPARATE],
-[
-  AC_CHECK_FUNCS_ONCE([strerror])
-  gl_PREREQ_STRERROR
-  if test $ac_cv_func_strerror = no; then
-    HAVE_DECL_STRERROR=0
-    gl_cv_func_working_strerror=no
-  else
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_ERRNO_H])
+  m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+    AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
+  ])
+  if test -z "$ERRNO_H"; then
     AC_CACHE_CHECK([for working strerror function],
      [gl_cv_func_working_strerror],
      [AC_RUN_IFELSE(
-       [AC_LANG_PROGRAM([
-#include <string.h>
-        ], [return !*strerror (-2);])],
-       [gl_cv_func_working_strerror=yes], [gl_cv_func_working_strerror=no],
-       [dnl assume success except on Interix
-       AC_EGREP_CPP([assuming success], [
-#ifndef __INTERIX
-  assuming success
-#endif
-       ], [gl_cv_func_working_strerror=yes],
-       [gl_cv_func_working_strerror=no])])])
-    if test $gl_cv_func_working_strerror = no ; then
+        [AC_LANG_PROGRAM(
+           [[#include <string.h>
+             #include <errno.h>
+           ]],
+           [[int result = 0;
+             char *str;
+             if (!*strerror (-2)) result |= 1;
+             errno = 0;
+             str = strerror (0);
+             if (!*str) result |= 2;
+             if (errno) result |= 4;
+             if (strstr (str, "nknown") || strstr (str, "ndefined"))
+               result |= 8;
+             return result;]])],
+        [gl_cv_func_working_strerror=yes],
+        [gl_cv_func_working_strerror=no],
+        [dnl Be pessimistic on cross-compiles for now.
+         gl_cv_func_working_strerror=no])
+    ])
+    if test $gl_cv_func_working_strerror = no; then
+      dnl The system's strerror() fails to return a string for out-of-range
+      dnl integers. Replace it.
       REPLACE_STRERROR=1
     fi
+    m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
+      dnl If the system's strerror_r or __xpg_strerror_r clobbers strerror's
+      dnl buffer, we must replace strerror.
+      case "$gl_cv_func_strerror_r_works" in
+        *no) REPLACE_STRERROR=1 ;;
+      esac
+    ])
+  else
+    dnl The system's strerror() cannot know about the new errno values we add
+    dnl to <errno.h>. Replace it.
+    REPLACE_STRERROR=1
   fi
 ])
-
-# Prerequisites of lib/strerror.c.
-AC_DEFUN([gl_PREREQ_STRERROR], [
-  :
-])