1/* Convert UTC calendar time to simple time. Like mktime but assumes UTC.
2
3 Copyright (C) 1994-2024 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#ifndef _LIBC
21# include <libc-config.h>
22#endif
23
24#include <time.h>
25#include <errno.h>
26
27#include "mktime-internal.h"
28
29__time64_t
30__timegm64 (struct tm *tmp)
31{
32 static mktime_offset_t gmtime_offset;
33 tmp->tm_isdst = 0;
34 return __mktime_internal (tp: tmp, __gmtime64_r, offset: &gmtime_offset);
35}
36
37#if defined _LIBC && __TIMESIZE != 64
38
39libc_hidden_def (__timegm64)
40
41time_t
42timegm (struct tm *tmp)
43{
44 struct tm tm = *tmp;
45 __time64_t t = __timegm64 (&tm);
46 if (in_time_t_range (t))
47 {
48 *tmp = tm;
49 return t;
50 }
51 else
52 {
53 __set_errno (EOVERFLOW);
54 return -1;
55 }
56}
57
58#endif
59

source code of glibc/time/timegm.c