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POSIX_OPENPT(3) Linux Programmer's Manual POSIX_OPENPT(3)

NAME

     posix_openpt - open a pseudoterminal device

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(): _XOPEN_SOURCE >= 600

DESCRIPTION

     The  posix_openpt()  function  opens  an  unused  pseudoterminal 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 nonnegative file descriptor  which
     is  the  lowest  numbered  unused  file  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.

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).

     +---------------+---------------+---------+
     |Interface      | Attribute     | Value   |
     +---------------+---------------+---------+
     |posix_openpt() | Thread safety | MT-Safe |
     +---------------+---------------+---------+

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008.

     posix_openpt() is part of  the  UNIX  98  pseudoterminal  support  (see
     pts(4)).

NOTES

     Some  older  UNIX  implementations  that support System V (aka UNIX 98)
     pseudoterminals don't have this function, but it is easy to implement:

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

     Calling posix_openpt() creates a pathname for the  corresponding  pseu-
     doterminal  slave  device.   The  pathname  of  the slave device can be
     obtained using ptsname(3).  The slave device pathname  exists  only  as
     long as the master device is open.

SEE ALSO

     open(2), getpt(3), grantpt(3), ptsname(3), unlockpt(3), pts(4), pty(7)

COLOPHON

     This  page  is  part of release 4.16 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/.

                                2017-09-15                   POSIX_OPENPT(3)