update NEWS.stable

[gnulib.git] / lib / mktime.c

diff --git a/lib/mktime.c b/lib/mktime.c
index d35bdd0..fc27adf 100644 (file)
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -1,5 +1,5 @@
-/* Convert a `struct tm' to a time_t value.
-   Copyright (C) 1993-1999, 2002-2007, 2009-2011 Free Software Foundation, Inc.
+/* Convert a 'struct tm' to a time_t value.
+   Copyright (C) 1993-1999, 2002-2007, 2009-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Paul Eggert <eggert@twinsun.com>.
 
@@ -14,8 +14,7 @@
    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. */
+   with this program; if not, see <http://www.gnu.org/licenses/>.  */
 
 /* Define this to have a standalone program to test this implementation of
    mktime.  */
@@ -25,26 +24,8 @@
 # include <config.h>
 #endif
 
-/* Some of the code in this file assumes that signed integer overflow
-   silently wraps around.  This assumption can't easily be programmed
-   around, nor can it be checked for portably at compile-time or
-   easily eliminated at run-time.
-
-   Define WRAPV to 1 if the assumption is valid.  Otherwise, define it
-   to 0; this forces the use of slower code that, while not guaranteed
-   by the C Standard, works on all production platforms that we know
-   about.  */
-#ifndef WRAPV
-# if (__GNUC__ == 4 && 4 <= __GNUC_MINOR__) || 4 < __GNUC__
-#  pragma GCC optimize ("wrapv")
-#  define WRAPV 1
-# else
-#  define WRAPV 0
-# endif
-#endif
-
 /* Assume that leap seconds are possible, unless told otherwise.
-   If the host has a `zic' command with a `-L leapsecondfilename' option,
+   If the host has a 'zic' command with a '-L leapsecondfilename' option,
    then it supports leap seconds; otherwise it probably doesn't.  */
 #ifndef LEAP_SECONDS_POSSIBLE
 # define LEAP_SECONDS_POSSIBLE 1
@@ -64,12 +45,36 @@
 # define mktime my_mktime
 #endif /* DEBUG */
 
+/* Some of the code in this file assumes that signed integer overflow
+   silently wraps around.  This assumption can't easily be programmed
+   around, nor can it be checked for portably at compile-time or
+   easily eliminated at run-time.
+
+   Define WRAPV to 1 if the assumption is valid and if
+     #pragma GCC optimize ("wrapv")
+   does not trigger GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793>.
+   Otherwise, define it to 0; this forces the use of slower code that,
+   while not guaranteed by the C Standard, works on all production
+   platforms that we know about.  */
+#ifndef WRAPV
+# if ((__GNUC__ == 4 && 4 <= __GNUC_MINOR__) || 4 < __GNUC__) && defined __GLIBC__
+#  pragma GCC optimize ("wrapv")
+#  define WRAPV 1
+# else
+#  define WRAPV 0
+# endif
+#endif
+
+/* Verify a requirement at compile-time (unlike assert, which is runtime).  */
+#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
+
 /* A signed type that is at least one bit wider than int.  */
 #if INT_MAX <= LONG_MAX / 2
 typedef long int long_int;
 #else
 typedef long long int long_int;
 #endif
+verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
 
 /* Shift A right by B bits portably, by dividing A by 2**B and
    truncating towards minus infinity.  A and B should be free of side
@@ -113,7 +118,7 @@ typedef long long int long_int;
 #define TYPE_MAXIMUM(t) \
   ((t) (! TYPE_SIGNED (t) \
         ? (t) -1 \
-        : (((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) << 1) + 1)))
+        : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
 
 #ifndef TIME_T_MIN
 # define TIME_T_MIN TYPE_MINIMUM (time_t)
@@ -123,9 +128,6 @@ typedef long long int long_int;
 #endif
 #define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
 
-/* Verify a requirement at compile-time (unlike assert, which is runtime).  */
-#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
-
 verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
 verify (twos_complement_arithmetic,
         (TYPE_TWOS_COMPLEMENT (int)
@@ -196,8 +198,6 @@ ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1,
             int year0, int yday0, int hour0, int min0, int sec0)
 {
   verify (C99_integer_division, -1 / 2 == 0);
-  verify (long_int_year_and_yday_are_wide_enough,
-          INT_MAX == INT_MAX * (long_int) 2 / 2);
 
   /* Compute intervening leap days correctly even if year is negative.
      Take care to avoid integer overflow here.  */
@@ -580,7 +580,7 @@ mktime (struct tm *tp)
 {
 #ifdef _LIBC
   /* POSIX.1 8.1.1 requires that whenever mktime() is called, the
-     time zone names contained in the external variable `tzname' shall
+     time zone names contained in the external variable 'tzname' shall
      be set as if the tzset() function had been called.  */
   __tzset ();
 #endif
@@ -733,6 +733,6 @@ main (int argc, char **argv)
 \f
 /*
 Local Variables:
-compile-command: "gcc -DDEBUG -Wall -W -O2 -g mktime.c -o mktime"
+compile-command: "gcc -DDEBUG -I. -Wall -W -O2 -g mktime.c -o mktime"
 End:
 */