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

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       grantpt() , open() , ptsname() , the  Base  Definitions  volume  of  IEEE Std 1003.1-2001,
       <stdlib.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .