pmCtime man page
pmCtime — format the date and time for a reporting timezone
char *pmCtime(const time_t *clock, char *buf);
cc ... -lpcp
pmCtime is very similar to ctime(3), except the timezone used is the current “reporting timezone” (rather than the default TZ environment variable scheme), and the result is returned into a caller-declared buffer (rather than a private buffer).
Like ctime(3) the time to be converted is passed via clock, and the result in buf is fixed width fields in the format:
Fri Sep 13 00:00:00 1986\n\0
The result buffer buf must be at least 26 bytes long, and no attempt is made to check this. pmCtime returns buf as the value of the function.
The default current reporting timezone is as defined by the TZ environment variable, so pmCtime and ctime(3) will initially produce similar encoding of the date and time.
Use pmNewZone(3), pmNewContextZone(3) or pmUseZone(3) to establish a new current reporting timezone that will effect pmCtime but not ctime(3).
ctime(3), PMAPI(3), pmLocaltime(3), pmNewContextZone(3), pmNewZone(3) and pmUseZone(3).
pmLocaltime(3), __pmMktime(3), pmNewContextZone(3), pmNewZone(3), pmUseZone(3), pmWhichZone(3).