X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fstrerror.m4;h=3989844b2235472d0d97d40894247bb113e7db90;hb=23eecb48e39afd0d267d64d40ba6bf97aa865e13;hp=048b03c0c84ae63902c8618e2ba8af9312c41ae3;hpb=0447b703359c908678dc2a5d105026ec73a652bb;p=gnulib.git

diff --git a/m4/strerror.m4 b/m4/strerror.m4
index 048b03c0c..3989844b2 100644
--- a/m4/strerror.m4
+++ b/m4/strerror.m4
@@ -1,5 +1,5 @@
-# strerror.m4 serial 14
-dnl Copyright (C) 2002, 2007-2011 Free Software Foundation, Inc.
+# strerror.m4 serial 17
+dnl Copyright (C) 2002, 2007-2013 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.
@@ -8,33 +8,37 @@ AC_DEFUN([gl_FUNC_STRERROR],
 [
   AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_REQUIRE([gl_HEADER_ERRNO_H])
+  AC_REQUIRE([gl_FUNC_STRERROR_0])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   m4_ifdef([gl_FUNC_STRERROR_R_WORKS], [
     AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
   ])
-  if test -z "$ERRNO_H"; then
+  if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
     AC_CACHE_CHECK([for working strerror function],
      [gl_cv_func_working_strerror],
      [AC_RUN_IFELSE(
         [AC_LANG_PROGRAM(
            [[#include <string.h>
-             #include <errno.h>
            ]],
-           [[int result = 0;
-             if (!*strerror (-2)) result |= 1;
-             errno = 0;
-             if (!*strerror (0)) result |= 2;
-             if (errno) result |= 4;
-             return result;]])],
+           [[if (!*strerror (-2)) return 1;]])],
         [gl_cv_func_working_strerror=yes],
         [gl_cv_func_working_strerror=no],
-        [dnl Be pessimistic on cross-compiles for now.
-         gl_cv_func_working_strerror=no])
+        [case "$host_os" in
+                   # Guess yes on glibc systems.
+           *-gnu*) gl_cv_func_working_strerror="guessing yes" ;;
+                   # If we don't know, assume the worst.
+           *)      gl_cv_func_working_strerror="guessing no" ;;
+         esac
+        ])
     ])
-    if test $gl_cv_func_working_strerror = no; then
-      dnl The system's strerror() fails to return a string for out-of-range
-      dnl integers. Replace it.
-      REPLACE_STRERROR=1
-    fi
+    case "$gl_cv_func_working_strerror" in
+      *yes) ;;
+      *)
+        dnl The system's strerror() fails to return a string for out-of-range
+        dnl integers. Replace it.
+        REPLACE_STRERROR=1
+        ;;
+    esac
     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.
@@ -44,7 +48,49 @@ AC_DEFUN([gl_FUNC_STRERROR],
     ])
   else
     dnl The system's strerror() cannot know about the new errno values we add
-    dnl to <errno.h>. Replace it.
+    dnl to <errno.h>, or any fix for strerror(0). Replace it.
     REPLACE_STRERROR=1
   fi
 ])
+
+dnl Detect if strerror(0) passes (that is, does not set errno, and does not
+dnl return a string that matches strerror(-1)).
+AC_DEFUN([gl_FUNC_STRERROR_0],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  REPLACE_STRERROR_0=0
+  AC_CACHE_CHECK([whether strerror(0) succeeds],
+   [gl_cv_func_strerror_0_works],
+   [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#include <string.h>
+           #include <errno.h>
+         ]],
+         [[int result = 0;
+           char *str;
+           errno = 0;
+           str = strerror (0);
+           if (!*str) result |= 1;
+           if (errno) result |= 2;
+           if (strstr (str, "nknown") || strstr (str, "ndefined"))
+             result |= 4;
+           return result;]])],
+      [gl_cv_func_strerror_0_works=yes],
+      [gl_cv_func_strerror_0_works=no],
+      [case "$host_os" in
+                 # Guess yes on glibc systems.
+         *-gnu*) gl_cv_func_strerror_0_works="guessing yes" ;;
+                 # If we don't know, assume the worst.
+         *)      gl_cv_func_strerror_0_works="guessing no" ;;
+       esac
+      ])
+  ])
+  case "$gl_cv_func_strerror_0_works" in
+    *yes) ;;
+    *)
+      REPLACE_STRERROR_0=1
+      AC_DEFINE([REPLACE_STRERROR_0], [1], [Define to 1 if strerror(0)
+        does not return a message implying success.])
+      ;;
+  esac
+])