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posix_openpt

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)