view lib/mktime-internal.h @ 18303:8b34efae5441

Port mktime_internal offset to unsigned time_t This avoids some assumptions about wraparound arithmetic on signed integer overflow. * lib/mktime-internal.h (mktime_offset_t): New type. (mktime_internal): Use it in decl. * lib/mktime.c, lib/timegm.c (mktime_offset_t) [_LIBC]: New type. * lib/mktime.c (__mktime_internal, localtime_offset): * lib/timegm.c (timegm): Use it. * m4/mktime.m4 (gl_TIME_T_IS_SIGNED): New macro. (gl_FUNC_MKTIME): Require it.
author Paul Eggert <eggert@cs.ucla.edu>
date Sun, 01 May 2016 11:44:51 -0700
parents 465038ef6bc4
children 12df2165ec1c
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/* mktime variant that also uses an offset guess

   Copyright 2016 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this program; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <time.h>

/* mktime_offset_t is a signed type wide enough to hold a UTC offset
   in seconds, and used as part of the type of the offset-guess
   argument to mktime_internal.  Use time_t on platforms where time_t
   is signed, to be compatible with platforms like BeOS that export
   this implementation detail of mktime.  On platforms where time_t is
   unsigned, GNU and POSIX code can assume 'int' is at least 32 bits
   which is wide enough for a UTC offset.  */

#if TIME_T_IS_SIGNED
typedef time_t mktime_offset_t;
#else
typedef int mktime_offset_t;
#endif

time_t mktime_internal (struct tm *,
                        struct tm * (*) (time_t const *, struct tm *),
                        mktime_offset_t *);