HP-UX Reference (11i v2 07/12) - 3 Library Functions N-Z (vol 7)

unlockpt(3C) unlockpt(3C)

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 coun-

terpart. 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.