getpt(3) -- Linux man page
NAMEgetpt - open the pseudo-terminal master (PTM)
#include <stdlib.h> int getpt(void)
DESCRIPTIONgetpt() opens a pseudo-terminal master and returns its file descriptor. It is equivalent to open(/dev/ptmx,O_RDWR|O_NOCTTY) on Linux systems, though the pseudo-terminal master is located elsewhere on some systems that use GNU Libc.
RETURN VALUEgetpt() returns an open file descriptor upon successful completion. Otherwise, it returns -1 and sets errno to indicate the error.
CONFORMING TOgetpt() is specific to GNU Libc.
SEE ALSOptmx(4), grantpt(3), unlockpt(3), ptsname(3)