unlockpt(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON

UNLOCKPT(3)               Linux Programmer's Manual              UNLOCKPT(3)

NAME         top

       unlockpt - unlock a pseudoterminal master/slave pair

SYNOPSIS         top

       #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 ||
                   (_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED)
           Glibc 2.23 and earlier:
               _XOPEN_SOURCE

DESCRIPTION         top

       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         top

       When successful, unlockpt() returns 0.  Otherwise, it returns -1 and
       sets errno appropriately.

ERRORS         top

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

       EINVAL The fd argument is not associated with a master
              pseudoterminal.

VERSIONS         top

       unlockpt() is provided in glibc since version 2.1.

ATTRIBUTES         top

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

       ┌───────────┬───────────────┬─────────┐
       │Interface  Attribute     Value   │
       ├───────────┼───────────────┼─────────┤
       │unlockpt() │ Thread safety │ MT-Safe │
       └───────────┴───────────────┴─────────┘

CONFORMING TO         top

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

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 5.08 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

                                 2017-07-13                      UNLOCKPT(3)

Pages that refer to this page: ioctl_tty(2)getpt(3)grantpt(3)posix_openpt(3)ptsname(3)ptsname_r(3)ptmx(4)pts(4)tty_ioctl(4)pty(7)