PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

NAME

       unlockpt — unlock a pseudo-terminal master/slave pair

SYNOPSIS

       #include <stdlib.h>

       int unlockpt(int fildes);

DESCRIPTION

       The unlockpt() function shall unlock the slave pseudo-terminal device associated with the master to which
       fildes refers.

       Conforming applications shall ensure that they call unlockpt() before opening the slave side of a pseudo-
       terminal device.

RETURN VALUE

       Upon  successful  completion,  unlockpt()  shall return 0. Otherwise, it shall return -1 and set errno to
       indicate the error.

ERRORS

       The unlockpt() function may fail if:

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

       EINVAL The fildes argument is not associated with a master pseudo-terminal device.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       See the RATIONALE section for posix_openpt().

FUTURE DIRECTIONS

       None.

SEE ALSO

       grantpt(), open(), posix_openpt(), ptsname()

       The Base Definitions volume of POSIX.1‐2017, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee  document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                      UNLOCKPT(3POSIX)