zephyr/include/sys/timeutil.h

59 lines
1.5 KiB
C

/*
* Copyright (c) 2019 Peter Bigot Consulting, LLC
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Utilities supporting operation on time data structures.
*
* POSIX defines gmtime() to convert from time_t to struct tm, but all
* inverse transformations are non-standard or require access to time
* zone information. timeutil_timegm() implements the functionality
* of the GNU extension timegm() function, but changes the error value
* as @c EOVERFLOW is not a standard C error identifier.
*
* timeutil_timegm64() is provided to support full precision
* conversion on platforms where @c time_t is limited to 32 bits.
*/
#ifndef ZEPHYR_INCLUDE_SYS_TIMEUTIL_H_
#define ZEPHYR_INCLUDE_SYS_TIMEUTIL_H_
#include <time.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Convert broken-down time to a POSIX epoch offset in seconds.
*
* @param tm pointer to broken down time.
*
* @return the corresponding time in the POSIX epoch time scale.
*
* @see http://man7.org/linux/man-pages/man3/timegm.3.html
*/
s64_t timeutil_timegm64(const struct tm *tm);
/**
* @brief Convert broken-down time to a POSIX epoch offset in seconds.
*
* @param tm pointer to broken down time.
*
* @return the corresponding time in the POSIX epoch time scale. If
* the time cannot be represented then @c (time_t)-1 is returned and
* @c errno is set to @c ERANGE`.
*
* @see http://man7.org/linux/man-pages/man3/timegm.3.html
*/
time_t timeutil_timegm(const struct tm *tm);
#ifdef __cplusplus
}
#endif
#endif /* ZEPHYR_INCLUDE_SYS_TIMEUTIL_H_ */