Name

posix_openpt — open a pseudo-terminal device

Synopsis

#include <stdlib.h>
#include <fcntl.h>
int posix_openpt( int   flags);
[Note] Note
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 implementations 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

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

COLOPHON

This page is part of release 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


Copyright (C) 2004 Michael Kerrisk

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