Library Functions Manual
NAME unlockpt — unlock the slave pseudo-terminal device
LIBRARY Standard C Library (libc, -lc)
SYNOPSIS #include <stdlib.h>
DESCRIPTION The unlockpt() unlocks access to the pseudo-terminal device corresponding to the master pseudo-terminal device associated with fildes. Conforming applications must call this function before opening the slave pseudo-terminal device.
RETURN VALUES If successful, unlockpt() returns 0; otherwise a value of -1 is returned and errno is set to indicate the error.
() function will fail if:
the corresponding pseudo-terminal device could not be accessed.
fildes is not a valid descriptor.
fildes is not associated with a master pseudo-terminal device.
NOTES In NetBSD unlockpt() does nothing.
STANDARDS The unlockpt() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”). Its first release was in X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”).