POSIX_OPENPT

Section: Linux Programmer's Manual (3)
Updated: 2007-07-26
Index Return to Main Contents

NAME

posix_openpt - open a pseudo-terminal 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(): _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);
}

COLOPHON

This page is part of release 3.22 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/.