timegm(3) Library Functions Manual timegm(3) timegm, timelocal - gmtime localtime (libc -lc) #include [[]] time_t timelocal(struct tm *tm); time_t timegm(struct tm *tm); glibc ( feature_test_macros(7)): timelocal() timegm(): glibc 2.19: _DEFAULT_SOURCE glibc 2.19 : _BSD_SOURCE || _SVID_SOURCE timelocal() timegm() localtime(3) gmtime(3). ( 1970-01-01 00:00:00 +0000 UTC). timelocal() timegm() (UTC). ( ) time_t. (time_t) -1 errno . EOVERFLOW . attributes(7). +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ | | | | +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ |timelocal() | | (MT-Safe) | |timegm() | | | +----------------------+------------------------------------+----------------------------------------------------------------------------------------+ BSD. (BSD). timelocal() POSIX mktime(3). . gmtime(3) localtime(3) mktime(3) tzset(3) 3 . . : . 6.18 8 2026 timegm(3)