GMTIME (man3p)
gmtime, gmtime_r — convert a time value to a broken-down UTC time
gmtime, gmtime_r — convert a time value to a broken-down UTC time
mktime — convert broken-down time into time since the Epoch
pthread_mutex_lock, pthread_mutex_trylock, pthread_mutex_unlock — lock and unlock a mutex
aio_write — asynchronous write to a file
posix_trace_create, posix_trace_create_withlog, posix_trace_flush, posix_trace_shutdown — trace stream initialization, flush, and shutdown from a process (TRACING)
creat — create a new file or rewrite an existing one
msgctl — XSI message control operations
getnetbyaddr, getnetbyname, getnetent — network database functions
inet_ntop, inet_pton — convert IPv4 and IPv6 addresses between binary and text form
fegetexceptflag, fesetexceptflag — get and set floating-point status flags