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



NAME
       unlockpt - unlock a pseudoterminal master/slave pair

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

DESCRIPTION
       The  unlockpt() function unlocks the slave pseudoterminal device corre-
       sponding to the master pseudoterminal referred to by fd.

       unlockpt() should be called before opening the slave side  of  a  pseu-
       doterminal.

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

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 in glibc since version 2.1.

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

       +-----------+---------------+---------+
       |Interface  | Attribute     | Value   |
       +-----------+---------------+---------+
       |unlockpt() | Thread safety | MT-Safe |
       +-----------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

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

COLOPHON
       This page is part of release 4.16 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)