NAME
unlockpt — unlock a STREAMS pty master and slave pair
SYNOPSIS
int unlockpt (int fildes);
DESCRIPTION
The passed parameter,
fildes,
is a file descriptor that is returned from a successful open of
a master pty (pseudo-terminal) device. The
unlockpt()
function unlocks a slave pty from its associated master counterpart.
It does this by clearing a lock flag so that the slave pty can be
opened. For security reason,
grantpt(3C)
must be executed before
unlockpt(3C).
RETURN VALUE
Upon successful completion, the
unlockpt()
function returns a value of 0 (zero). Otherwise, it returns a value of -1.
Failure may result under the following conditions:
The file descriptor specified by the
fildes
parameter is not an open file descriptor.
The file descriptor specified by the
fildes
parameter is not associated with a STREAMS pty master device.
EXAMPLES
The following example shows how
unlockpt
is typically used.
int fd_master, fd_slave;
char *slave;
...
fd_master = open("/dev/ptmx", O_RDWR);
grantpt(fd_master);
unlockpt(fd_master);
slave = ptsname(fd_master);
fd_slave = open(slave, O_RDWR);
ioctl(fd_slave, I_PUSH, "ptem");
ioctl(fd_slave, I_PUSH, "ldterm");
AUTHOR
unlockpt()
was developed by HP and OSF.
