POSIX_OPENPT(3)

NAME
posix_openpt - open a pseudo-terminal device

SYNOPSIS
#define _XOPEN_SOURCE
#include <stdlib.h>
#include <fcntl.h>

char *posix_openpt(int flags);

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, ptsname() 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).

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), unlock(3), pts(4), pty(7)