NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       posix_openpt - open a pseudoterminal device

SYNOPSIS         top

       #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         top

       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         top

       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         top

       See open(2).

VERSIONS         top

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

ATTRIBUTES         top

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

       ┌───────────────┬───────────────┬─────────┐
       │Interface      Attribute     Value   │
       ├───────────────┼───────────────┼─────────┤
       │posix_openpt() │ Thread safety │ MT-Safe │
       └───────────────┴───────────────┴─────────┘

CONFORMING TO         top

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

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

NOTES         top

       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
       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         top

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

COLOPHON         top

       This page is part of release 4.07 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/.

                                 2016-03-15                  POSIX_OPENPT(3)