(AC_FUNC_STRERROR_R): Pass a reasonably large buffer to strerror_r.

[gnulib.git] / m4 / strerror_r.m4

diff --git a/m4/strerror_r.m4 b/m4/strerror_r.m4
index 410dfdf..1e57f27 100644 (file)
--- a/m4/strerror_r.m4
+++ b/m4/strerror_r.m4
@@ -1,40 +1,67 @@
-#serial 2
+#serial 1001
+# Experimental replacement for the function in the latest CVS autoconf.
+# If the compile-test says strerror_r doesn't work, then resort to a
+# `run'-test that works on BeOS and segfaults on DEC Unix.
+# Use with the error.c file in ../lib.
 
-dnl From Jim Meyering.
-dnl Determine whether the strerror_r implementation is one of
-dnl the broken ones that returns `int' rather than `char*'.
-dnl Actually, this tests only whether it returns a scalar
-dnl or an array, but that should be enough.
-dnl On at least DEC UNIX 4.0[A-D] and HP-UX B.10.20, strerror_r
-dnl returns `int'.  This is used by lib/error.c.
+undefine([AC_FUNC_STRERROR_R])
 
-AC_DEFUN(jm_FUNC_STRERROR_R,
-[
-  # Check strerror_r
-  AC_CHECK_FUNCS([strerror_r])
-  if test $ac_cv_func_strerror_r = yes; then
-    AC_CHECK_HEADERS(string.h)
-    AC_CACHE_CHECK([for working strerror_r],
-                   jm_cv_func_working_strerror_r,
+# AC_FUNC_STRERROR_R
+# ------------------
+AC_DEFUN([AC_FUNC_STRERROR_R],
+[# Check strerror_r
+AC_CHECK_DECLS([strerror_r])
+AC_CHECK_FUNCS([strerror_r])
+if test $ac_cv_func_strerror_r = yes; then
+  AC_CHECK_HEADERS(string.h)
+  AC_CACHE_CHECK([for working strerror_r],
+                 ac_cv_func_strerror_r_works,
+   [
+    AC_TRY_COMPILE(
      [
-      AC_TRY_COMPILE(
-       [
 #       include <stdio.h>
 #       if HAVE_STRING_H
 #        include <string.h>
 #       endif
-       ],
+     ],
+     [
+       char buf[100];
+       char x = *strerror_r (0, buf, sizeof buf);
+     ],
+     ac_cv_func_strerror_r_works=yes,
+     ac_cv_func_strerror_r_works=no
+    )
+    if test $ac_cv_func_strerror_r_works = no; then
+      # strerror_r seems not to work, but now we have to choose between
+      # systems that have relatively inaccessible declarations for the
+      # function.  BeOS and DEC UNIX 4.0 fall in this category, but the
+      # former has a strerror_r that returns char*, while the latter
+      # has a strerror_r that returns `int'.
+      # This test should segfault on the DEC system.
+      AC_TRY_RUN(
        [
-        int buf; /* avoiding square brackets makes this easier */
-        char x = *strerror_r (0, buf, sizeof buf);
+#       include <stdio.h>
+#       include <string.h>
+
+       extern char *strerror_r ();
+
+       int
+       main ()
+       {
+         char buf[100];
+         char x = *strerror_r (0, buf, sizeof buf);
+         exit (!isalpha (x));
+       }
        ],
-       jm_cv_func_working_strerror_r=yes,
-       jm_cv_func_working_strerror_r=no
-      )
-      if test $jm_cv_func_working_strerror_r = yes; then
-       AC_DEFINE_UNQUOTED(HAVE_WORKING_STRERROR_R, 1,
-         [Define to 1 if strerror_r returns a string.])
-      fi
-    ])
-  fi
-])
+       ac_cv_func_strerror_r_works=yes,
+       ac_cv_func_strerror_r_works=no,
+       ac_cv_func_strerror_r_works=no)
+    fi
+
+    if test $ac_cv_func_strerror_r_works = yes; then
+      AC_DEFINE_UNQUOTED(HAVE_WORKING_STRERROR_R, 1,
+        [Define to 1 if `strerror_r' returns a string.])
+    fi
+  ])
+fi
+])# AC_FUNC_STRERROR_R