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  num‐
       bered  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.

ATTRIBUTES
   Multithreading (see pthreads(7))
       The posix_openpt() function is thread-safe.

CONFORMING TO
       posix_openpt() is part of the UNIX 98 pseudoterminal support (see pts(4)).  This  function
       is specified in POSIX.1-2001.

NOTES
       The  posix_openpt()  function  is  a recent invention in POSIX.  Some 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 pseudoterminal 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 3.74 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 http://www.kernel.org/doc/man-pages/.



                                            2014-06-03                            POSIX_OPENPT(3)