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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 4.15 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)