SYNOPSIS
       #include <stdlib.h>
       #include <fcntl.h>

       int posix_openpt(int flags);

   feature test macro requirements for glibc (see feature_test_macros(7)):

       posix_openpt(): _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600

DESCRIPTION
       The  posix_openpt()  function  opens  an  unused pseudo-terminal master
       device, returning a file descriptor that can be used to refer  to  that
       device.

       The  flags argument is a bit mask that ORs together zero or more of the
       following flags:

       O_RDWR Open the device for both reading and writing.  It  is  usual  to
              specify this flag.

       O_NOCTTY
              Do  not  make  this  device  the  controlling  terminal  for the
              process.

RETURN VALUE
       On success, posix_openpt() returns a non-negative file descriptor which
       is  the lowest numbered unused descriptor.  On failure, -1 is returned,
       and errno is set to indicate the error.

ERRORS
       see open(2).

VERSIONS
       Glibc support for posix_openpt() has been provided since version 2.2.1.

CONFORMING TO
       posix_openpt() is part  of  the  Unix98  pseudo-terminal  support  (see
       pts(4)).  this function is specified in posix.1-2001.

NOTES
       This  function  is  a recent invention in POSIX.  Some Unix implementa-
       tions that support System V (aka Unix 98) pseudo-terminals  don't  have
       this function, but it is easy to implement:

           int
           posix_openpt(int flags)
           {
               return open("/dev/ptmx", flags);
           }

SEE ALSO