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 de-
vice, returning a file descriptor that can be used to refer to that de-
vice.
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 file descriptor (a nonnegative in-
teger) which is the lowest numbered unused file descriptor. On fail-
ure, -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 at-
tributes(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 ob-
tained 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 5.07 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/.
2020-04-11 POSIX_OPENPT(3)