PTHREAD_TESTCANCEL (man3p)
pthread_testcancel — set cancelability state
pthread_testcancel — set cancelability state
getgrgid, getgrgid_r — get group database entry for a group ID
seed48 — seed a uniformly distributed pseudo-random non-negative long integer generator
llrint, llrintf, llrintl — round to the nearest integer value using current rounding direction
iswspace, iswspace_l — test for a white-space wide-character code
link, linkat — link one file to another file
putchar — put a byte on a stdout stream
tcsetattr — set the parameters associated with the terminal
strsignal — get name of signal
tsearch — search a binary search tree