glibc/time/mktime-internal.h

80 lines
3.0 KiB
C

/* Internals of mktime and related functions
Copyright 2016-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Eggert <eggert@cs.ucla.edu>.
The GNU C Library 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.
The GNU C Library 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 the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _LIBC
# include <time.h>
#endif
/* 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. In Glibc, it is always long int.
When in Gnulib, 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. */
#ifdef _LIBC
typedef long int mktime_offset_t;
#elif defined TIME_T_IS_SIGNED
typedef time_t mktime_offset_t;
#else
typedef int mktime_offset_t;
#endif
/* The source code uses identifiers like __time64_t for glibc
timestamps that can contain 64-bit values even when time_t is only
32 bits. These are just macros for the ordinary identifiers unless
compiling within glibc when time_t is 32 bits. */
#if ! (defined _LIBC && __TIMESIZE != 64)
# undef __time64_t
# define __time64_t time_t
# define __gmtime64_r __gmtime_r
# define __localtime64_r __localtime_r
# define __mktime64 mktime
# define __timegm64 timegm
#endif
#ifndef _LIBC
/* Although glibc source code uses leading underscores, Gnulib wants
ordinary names.
Portable standalone applications should supply a <time.h> that
declares a POSIX-compliant localtime_r, for the benefit of older
implementations that lack localtime_r or have a nonstandard one.
Similarly for gmtime_r. See the gnulib time_r module for one way
to implement this. */
# undef __gmtime_r
# undef __localtime_r
# define __gmtime_r gmtime_r
# define __localtime_r localtime_r
# define __mktime_internal mktime_internal
#endif
/* Subroutine of mktime. Return the time_t representation of TP and
normalize TP, given that a struct tm * maps to a time_t as performed
by FUNC. Record next guess for localtime-gmtime offset in *OFFSET. */
extern __time64_t __mktime_internal (struct tm *tp,
struct tm *(*func) (__time64_t const *,
struct tm *),
mktime_offset_t *offset) attribute_hidden;