utils-std

utils_timegm.c (628B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _DEFAULT_SOURCE // tm_gmtoff/tm_zone, timegm (POSIX.1-2024 mktime() future directions)
#include "./datetime_parse.h"
#include <time.h>
// Wrap timegm() to still get portable behavior while setting tm_gmtoff directly
// Effectively the opposite of gmtime()
time_t
utils_timegm(struct tm *tm)
{
	long gmtoff = tm->tm_gmtoff;
	tm->tm_isdst = 0;
	tm->tm_gmtoff = 0;
	tm->tm_zone = "UTC";
	time_t ret = timegm(tm);
	return ret - gmtoff;
}