Re: [Patch, libfortran, committed] PR 47802 Hack around POSIX draft localtime_r

[Janne Blomqvist]

On Fri, Mar 4, 2011 at 20:06, Jakub Jelinek <ja...@redhat.com> wrote:
> On Fri, Mar 04, 2011 at 07:54:29PM +0200, Janne Blomqvist wrote:
>> This should fix the problem reported on HP-UX 10.2. Committed as obvious:
>
> Well, it is not so obvious, you shouldn't be ignoring the return value from
> strftime, because if it fails, ltm will contain raondom undefined values.
> If there are different return values, you should just
> __builtin_choose_expr (__builtin_classify_type (localtime_r (timep, &ltm)) == 
> 5,
>                       failed = localtime_r (timep, &ltm) == NULL,
>                       failed = localtime_r (timep, &ltm) != 0);
> if (failed)
>  return 0;
> or something similar.

Fair enough, that does the trick. Patch that I just committed below.

Index: intrinsics/ctime.c
===================================================================
--- intrinsics/ctime.c  (revision 170680)
+++ intrinsics/ctime.c  (working copy)
@@ -40,11 +40,16 @@ strctime (char *s, size_t max, const tim
 {
 #ifdef HAVE_STRFTIME
   struct tm ltm;
-  /* Note: We can't use the return value of localtime_r, as some
-     targets provide localtime_r based on a draft of the POSIX
+  int failed;
+  /* Some targets provide a localtime_r based on a draft of the POSIX
      standard where the return type is int rather than the
      standardized struct tm*.  */
-  localtime_r (timep, &ltm);
+  __builtin_choose_expr (__builtin_classify_type (localtime_r (timep, &ltm))
+                        == 5,
+                        failed = localtime_r (timep, &ltm) == NULL,
+                        failed = localtime_r (timep, &ltm) != 0);
+  if (failed)
+    return 0;
   return strftime (s, max, "%c", &ltm);
 #else
   return 0;
Index: ChangeLog
===================================================================
--- ChangeLog   (revision 170680)
+++ ChangeLog   (working copy)
@@ -1,6 +1,12 @@
 2011-03-04  Janne Blomqvist  <j...@gcc.gnu.org>

        PR libfortran/47802
+       * intrinsics/ctime.c (strctime): Use builtins to check localtime_r
+       return value.
+
+2011-03-04  Janne Blomqvist  <j...@gcc.gnu.org>
+
+       PR libfortran/47802
        * intrinsics/ctime.c (strctime): Don't use return value of
        localtime_r.





-- 
Janne Blomqvist