Re: [bug-gnulib] gettimeofday() for Win32

[Martin Lambers]

On Thu, 25. Aug 2005, 15:32:00 +0200, Bruno Haible wrote:
> > If so, how can this be done?
> 
> It can be done by merging your .m4 file with Jim's one, and put a big
> #if inside lib/gettimeofday.c. 

OK, I had no better idea than defining GETTIMEOFDAY_USE_REPLACEMENTS if
the replacement functions should be used, and let the big #if test that.
Besides introducing another constat, this has the disadvantage that
rpl_tzset is compiled even when it is not activated by the tzset module.
There's probably a better way to do it.

> But first, can you please bring your proposed code up to gnulib
> standards?

Done.

> And compare the code with GNU clisp's gettimeofday emulations. (I wrote
> that code => no copyright problems when porting it to gnulib.)

I used your code, with one exception:

> What's the right way to fill the struct timezone?

Newer descriptions of the gettimeofday function replaced 'struct
timezone * tzp' with 'void * tzp' and state that "If tzp is not a null
pointer, the behavior is unspecified." See
http://www.opengroup.org/onlinepubs/009695399/functions/gettimeofday.html
The code below therefore simply ignores the tzp argument.

I also added a test module, using the test code from Jim Meyering's
tests in gettimeofday.m4.

Thanks for your comments,
Martin


diff -uNr gnulib/lib/gettimeofday.c gnulib-gettimeofday-work/lib/gettimeofday.c
--- gnulib/lib/gettimeofday.c   2005-05-14 08:03:58.000000000 +0200
+++ gnulib-gettimeofday-work/lib/gettimeofday.c 2005-08-25 17:01:47.000000000 
+0200
@@ -1,8 +1,9 @@
-/* Work around the bug in some systems whereby gettimeofday clobbers the
+/* Provide gettimeofday for systems that don't have it, or 
+   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.
    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.
+   Copyright (C) 2001, 2002, 2003, 2005 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
@@ -31,19 +32,35 @@
 
 #include <sys/types.h>
 
-#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
+#include <stdlib.h>
+
+#ifdef _WIN32
+#include <sys/timeb.h>
 #endif
 
-#include <stdlib.h>
+#include "gettimeofday.h"
+
+#ifndef HAVE_GETTIMEOFDAY
+int 
+gettimeofday (struct timeval *tp, void *tzp)
+{
+  if (tp != NULL)
+    {
+#ifdef _WIN32    
+      struct _timeb timebuf;
+      _ftime (&timebuf);
+      tp->tv_sec = timebuf.time;
+      tp->tv_usec = (long)(timebuf.millitm) * (1000000/1000);
+#else    
+      tp->tv_sec = time (NULL);
+      tp->tv_usec = 0;
+#endif
+    }
+  return 0;
+}
+#endif /* HAVE_GETTIMEOFDAY */
 
+#ifdef GETTIMEOFDAY_USE_REPLACEMENTS
 static struct tm *localtime_buffer_addr;
 
 /* This is a wrapper for localtime.  It is used only on systems for which
@@ -119,3 +136,4 @@
   tzset ();
   *localtime_buffer_addr = save;
 }
+#endif /* GETTIMEOFDAY_USE_REPLACEMENTS */
diff -uNr gnulib/lib/gettimeofday.h gnulib-gettimeofday-work/lib/gettimeofday.h
--- gnulib/lib/gettimeofday.h   1970-01-01 01:00:00.000000000 +0100
+++ gnulib-gettimeofday-work/lib/gettimeofday.h 2005-08-25 17:28:06.908471216 
+0200
@@ -0,0 +1,50 @@
+/* Provide gettimeofday for systems that don't have it, or 
+   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.
+   The tzset replacement is necessary for at least Solaris 2.5, 2.5.1, and 2.6.
+   Copyright (C) 2001, 2002, 2003, 2005 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
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef GETTIMEOFDAY_H
+#define GETTIMEOFDAY_H
+
+#include <config.h>
+
+#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
+
+#ifndef HAVE_STRUCT_TIMEVAL
+struct timeval
+{
+  time_t tv_sec;
+  suseconds_t tv_usec;
+};
+#endif
+
+#ifndef HAVE_GETTIMEOFDAY
+int gettimeofday (struct timeval *tp, void *tzp);
+#endif
+
+#endif /* GETTIMEOFDAY_H */
diff -uNr gnulib/m4/gettimeofday.m4 gnulib-gettimeofday-work/m4/gettimeofday.m4
--- gnulib/m4/gettimeofday.m4   2005-05-18 21:47:30.000000000 +0200
+++ gnulib-gettimeofday-work/m4/gettimeofday.m4 2005-08-25 17:57:28.232709232 
+0200
@@ -1,10 +1,20 @@
-#serial 7
+#serial 8
 
 # Copyright (C) 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
+[
+  AC_LIBSOURCES([gettimeofday.c, gettimeofday.h])
+  gl_PREREQ_GETTIMEOFDAY
+  AC_REPLACE_FUNCS(gettimeofday)
+  if test $ac_cv_func_gettimeofday = yes; then
+    AC_FUNC_GETTIMEOFDAY_CLOBBER
+  fi
+])
+
 dnl From Jim Meyering.
 dnl
 dnl See if gettimeofday clobbers the static buffer that localtime uses
@@ -62,11 +72,12 @@
 
     AC_DEFINE(gettimeofday, rpl_gettimeofday,
       [Define to rpl_gettimeofday if the replacement function should be used.])
-    gl_PREREQ_GETTIMEOFDAY
   fi
 ])
 
 AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
+  AC_DEFINE(GETTIMEOFDAY_USE_REPLACEMENTS, 1, 
+    [Define if some time related replacement functions should be used.])
   AC_LIBOBJ(gettimeofday)
   AC_DEFINE(gmtime, rpl_gmtime,
     [Define to rpl_gmtime if the replacement function should be used.])
@@ -77,4 +88,45 @@
 # Prerequisites of lib/gettimeofday.c.
 AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [
   AC_REQUIRE([AC_HEADER_TIME])
+
+  AC_CHECK_TYPE([suseconds_t], ,
+    [AC_DEFINE([suseconds_t], [int],
+       [Define to `int' if `suseconds_t' is missing.])
+    ],
+    [
+#    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
+    ])
+  
+  AC_CACHE_CHECK([for struct timeval], fu_cv_sys_struct_timeval,
+    [AC_TRY_COMPILE(
+      [
+#      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
+      ],
+      [static struct timeval x; x.tv_sec = x.tv_usec;],
+      fu_cv_sys_struct_timeval=yes,
+      fu_cv_sys_struct_timeval=no)
+    ])
+ 
+  if test $fu_cv_sys_struct_timeval = yes; then
+    AC_DEFINE(HAVE_STRUCT_TIMEVAL, 1,
+              [Define if struct timeval is declared in <time.h> or 
<sys/time.h>. ])
+  fi
 ])
diff -uNr gnulib/modules/gettimeofday 
gnulib-gettimeofday-work/modules/gettimeofday
--- gnulib/modules/gettimeofday 2004-09-22 17:11:04.000000000 +0200
+++ gnulib-gettimeofday-work/modules/gettimeofday       2005-08-25 
16:46:22.870142904 +0200
@@ -3,17 +3,19 @@
 
 Files:
 lib/gettimeofday.c
+lib/gettimeofday.h
 m4/gettimeofday.m4
 
 Depends-on:
 
 configure.ac:
-AC_FUNC_GETTIMEOFDAY_CLOBBER
+gl_FUNC_GETTIMEOFDAY
 
 Makefile.am:
 
 Include:
 <sys/time.h>
+"gettimeofday.h"
 
 License:
 GPL
diff -uNr gnulib/modules/gettimeofday-tests 
gnulib-gettimeofday-work/modules/gettimeofday-tests
--- gnulib/modules/gettimeofday-tests   1970-01-01 01:00:00.000000000 +0100
+++ gnulib-gettimeofday-work/modules/gettimeofday-tests 2005-08-25 
17:27:35.780203432 +0200
@@ -0,0 +1,11 @@
+Files:
+tests/test-gettimeofday.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-gettimeofday
+test_gettimeofday_SOURCES = test-gettimeofday.c
+
diff -uNr gnulib/tests/test-gettimeofday.c 
gnulib-gettimeofday-work/tests/test-gettimeofday.c
--- gnulib/tests/test-gettimeofday.c    1970-01-01 01:00:00.000000000 +0100
+++ gnulib-gettimeofday-work/tests/test-gettimeofday.c  2005-08-25 
17:25:15.797484040 +0200
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2005 Free Software Foundation
+ * Written by Jim Meyering.
+ *
+ * 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
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+
+#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 "gettimeofday.h"
+
+int
+main (int argc, char *argv[])
+{
+  suseconds_t dummy = 0;       /* just to test if this type is available */
+  time_t t = 0;
+  struct tm *lt;
+  struct tm saved_lt;
+  struct timeval tv;
+  lt = localtime (&t);
+  saved_lt = *lt;
+  gettimeofday (&tv, NULL);
+  if (memcmp (lt, &saved_lt, sizeof (struct tm)) != 0)
+    {
+      fprintf (stderr, "gettimeofday still clobbers the localtime buffer!\n");
+      return 1;
+    }
+  else
+    {
+      return 0;
+    }
+}