[Bug-gnulib] new module tzset; fixes for gettimeofday

[Paul Eggert]

I merged the following changes from coreutils.  The
gl_GETTIMEOFDAY_REPLACE_LOCALTIME macro is my own invention, though;
it removes duplication from gettimeofday.m4 and tzset.m4.

2003-08-14  Paul Eggert  <address@hidden>

        * lib/gettimeofday.c (rpl_gmtime, rpl_tzset): New functions.
        * m4/gettimeofday.m4 (gl_GETTIMEOFDAY_REPLACE_LOCALTIME): New macro.
        (AC_FUNC_GETTIMEOFDAY_CLOBBER): Use it.
        * m4/tzset.m4: New file.
        * modules/tzset: New file.

Index: lib/gettimeofday.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/gettimeofday.c,v
retrieving revision 1.4
diff -p -u -r1.4 gettimeofday.c
--- lib/gettimeofday.c  27 May 2002 16:42:55 -0000      1.4
+++ lib/gettimeofday.c  14 Aug 2003 21:51:23 -0000
@@ -1,7 +1,8 @@
 /* Work around the bug in some systems whereby gettimeofday clobbers the
    static buffer that localtime uses for it's return value.  The gettimeofday
    function from Mac OS X 10.0.4, i.e. Darwin 1.3.7 has this problem.
-   Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+   The tzset replacement is necessary for at least Solaris 2.5, 2.5.1, and 2.6.
+   Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,10 +22,12 @@
 
 #include <config.h>
 
-/* Disable the definitions of gettimeofday and localtime (from config.h)
+/* Disable the definitions of these functions (from config.h)
    so we can use the library versions here.  */
 #undef gettimeofday
+#undef gmtime
 #undef localtime
+#undef tzset
 
 #include <sys/types.h>
 
@@ -60,6 +63,18 @@ rpl_localtime (const time_t *timep)
   return tm;
 }
 
+/* Same as above, since gmtime and localtime use the same buffer.  */
+struct tm *
+rpl_gmtime (const time_t *timep)
+{
+  struct tm *tm = gmtime (timep);
+
+  if (! localtime_buffer_addr)
+    localtime_buffer_addr = tm;
+
+  return tm;
+}
+
 /* This is a wrapper for gettimeofday.  It is used only on systems for which
    gettimeofday clobbers the static buffer used for localtime's result.
 
@@ -83,4 +98,24 @@ rpl_gettimeofday (struct timeval *tv, st
   *localtime_buffer_addr = save;
 
   return result;
+}
+
+/* This is a wrapper for tzset. It is used only on systems for which
+   tzset may clobber the static buffer used for localtime's result.
+   Save and restore the contents of the buffer used for localtime's
+   result around the call to tzset.  */
+void
+rpl_tzset (void)
+{
+  struct tm save;
+
+  if (! localtime_buffer_addr)
+    {
+      time_t t = 0;
+      localtime_buffer_addr = localtime (&t);
+    }
+
+  save = *localtime_buffer_addr;
+  tzset ();
+  *localtime_buffer_addr = save;
 }
Index: m4/gettimeofday.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/gettimeofday.m4,v
retrieving revision 1.6
diff -p -u -r1.6 gettimeofday.m4
--- m4/gettimeofday.m4  31 Dec 2002 13:43:06 -0000      1.6
+++ m4/gettimeofday.m4  14 Aug 2003 21:51:23 -0000
@@ -1,4 +1,4 @@
-#serial 3
+#serial 4
 
 dnl From Jim Meyering.
 dnl
@@ -58,15 +58,22 @@ main ()
         jm_cv_func_gettimeofday_clobber=yes)
   ])
   if test $jm_cv_func_gettimeofday_clobber = yes; then
-    AC_LIBOBJ(gettimeofday)
-    AC_DEFINE(localtime, rpl_localtime,
-      [Define to rpl_localtime if the replacement function should be used.])
+    gl_GETTIMEOFDAY_REPLACE_LOCALTIME
+
     AC_DEFINE(gettimeofday, rpl_gettimeofday,
       [Define to rpl_gettimeofday if the replacement function should be used.])
     AC_DEFINE(GETTIMEOFDAY_CLOBBERS_LOCALTIME_BUFFER, 1,
       [Define if gettimeofday clobbers localtime's static buffer.])
     gl_PREREQ_GETTIMEOFDAY
   fi
+])
+
+AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
+  AC_LIBOBJ(gettimeofday)
+  AC_DEFINE(gmtime, rpl_gmtime,
+    [Define to rpl_gmtime if the replacement function should be used.])
+  AC_DEFINE(localtime, rpl_localtime,
+    [Define to rpl_localtime if the replacement function should be used.])
 ])
 
 # Prerequisites of lib/gettimeofday.c.
--- /dev/null   Tue Mar 18 13:55:57 2003
+++ modules/tzset       Mon Aug 11 21:22:49 2003
@@ -0,0 +1,20 @@
+Description:
+tzset - initialize time conversion information
+
+Files:
+m4/tzset.m4
+
+Depends-on:
+gettimeofday
+
+configure.ac:
+gl_FUNC_TZSET_CLOBBER
+
+Makefile.am:
+
+Include:
+<time.h>
+
+Maintainer:
+Jim Meyering
+
--- /dev/null   Tue Mar 18 13:55:57 2003
+++ m4/tzset.m4 Mon Aug 11 21:24:17 2003
@@ -0,0 +1,62 @@
+#serial 1
+# See if we have a working tzset function.
+# If so, arrange to compile the wrapper function.
+# For at least Solaris 2.5.1 and 2.6, this is necessary
+# because tzset can clobber the contents of the buffer
+# used by localtime.
+
+# Written by Paul Eggert and Jim Meyering.
+
+AC_DEFUN([gl_FUNC_TZSET_CLOBBER],
+[
+  AC_REQUIRE([AC_HEADER_TIME])
+  AC_CACHE_CHECK([whether tzset clobbers localtime buffer],
+                 gl_cv_func_tzset_clobber,
+  [
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+#include <stdlib.h>
+
+int
+main ()
+{
+  time_t t1 = 853958121;
+  struct tm *p, s;
+  putenv ("TZ=GMT0");
+  p = localtime (&t1);
+  s = *p;
+  putenv ("TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00");
+  tzset ();
+  exit (p->tm_year != s.tm_year
+        || p->tm_mon != s.tm_mon
+        || p->tm_mday != s.tm_mday
+        || p->tm_hour != s.tm_hour
+        || p->tm_min != s.tm_min
+        || p->tm_sec != s.tm_sec);
+}
+  ]])],
+       [gl_cv_func_tzset_clobber=no],
+       [gl_cv_func_tzset_clobber=yes],
+       [gl_cv_func_tzset_clobber=yes])])
+
+  AC_DEFINE(HAVE_RUN_TZSET_TEST, 1,
+    [Define to 1 if you have run the test for working tzset.])
+
+  if test $gl_cv_func_tzset_clobber = yes; then
+    gl_GETTIMEOFDAY_REPLACE_LOCALTIME
+
+    AC_DEFINE(tzset, rpl_tzset,
+      [Define to rpl_tzset if the wrapper function should be used.])
+    AC_DEFINE(TZSET_CLOBBERS_LOCALTIME_BUFFER, 1,
+      [Define if tzset clobbers localtime's static buffer.])
+  fi
+])