GETCHAR (man3p)
getchar — get a byte from a stdin stream
getchar — get a byte from a stdin stream
strtoumax — convert a string to an integer type
nearbyint, nearbyintf, nearbyintl — floating-point rounding functions
pthread_attr_getschedparam, pthread_attr_setschedparam — get and set the schedparam attribute
setprotoent — network protocol database functions
poll — input/output multiplexing
pthread_self — get the calling thread ID
mbrlen — get number of bytes in a character (restartable)
cpow, cpowf, cpowl — complex power functions
atoi — convert a string to an integer