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 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
       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 5.10 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)