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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 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).

       ┌───────────┬───────────────┬─────────┐
       │InterfaceAttributeValue   │
       ├───────────┼───────────────┼─────────┤
       │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 5.02 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)