unlockpt - Man Page

unlock a pseudoterminal master/slave pair

Library

Standard C library (libc, -lc)

Synopsis

#define _XOPEN_SOURCE
#include <stdlib.h>

int unlockpt(int fd);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

unlockpt():

    Since glibc 2.24:
        _XOPEN_SOURCE >= 500
    Glibc 2.23 and earlier:
        _XOPEN_SOURCE

Description

The unlockpt() function unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by the file descriptor fd.

unlockpt() should be called before opening the slave side of a pseudoterminal.

Return Value

When successful, unlockpt() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

Errors

EBADF

The fd argument is not a file descriptor open for writing.

EINVAL

The fd argument is not associated with a master pseudoterminal.

Versions

unlockpt() is provided since glibc 2.1.

Attributes

For an explanation of the terms used in this section, see attributes(7).

InterfaceAttributeValue
unlockpt()Thread safetyMT-Safe

Standards

POSIX.1-2001, POSIX.1-2008.

See Also

grantpt(3), posix_openpt(3), ptsname(3), pts(4), pty(7)

Referenced By

getpt(3), grantpt(3), ioctl_tty(2), posix_openpt(3), pts(4), ptsname(3), pty(7).

2022-12-15 Linux man-pages 6.02