posix_openpt (2)

Leading comments

Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
All rights reserved.

Portions of this software were developed under sponsorship from Snow
B.V., the Netherlands.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce t...

(The comments found at the beginning of the groff file "man2/posix_openpt.2freebsd".)

NAME

posix_openpt - open a pseudo-terminal device

LIBRARY

Lb libc

SYNOPSIS

In stdlib.h In fcntl.h Ft int Fn posix_openpt int oflag

DESCRIPTION

The Fn posix_openpt function allocates a new pseudo-terminal and establishes a connection with its master device. A slave device shall be created in /dev/pts After the pseudo-terminal has been allocated, the slave device should have the proper permissions before it can be used (see grantpt(3)). The name of the slave device can be determined by calling ptsname(3).

The file status flags and file access modes of the open file description shall be set according to the value of Fa oflag . Values for Fa oflag are constructed by a bitwise-inclusive OR of flags from the following list, defined in In fcntl.h :

O_RDWR

Open for reading and writing.

O_NOCTTY

If set Fn posix_openpt shall not cause the terminal device to become the controlling terminal for the process.

O_CLOEXEC

Set the close-on-exec flag for the new file descriptor.

The Fn posix_openpt function shall fail when Fa oflag contains other values.

RETURN VALUES

Upon successful completion, the Fn posix_openpt function shall allocate a new pseudo-terminal device and return a non-negative integer representing a file descriptor, which is connected to its master device. Otherwise, -1 shall be returned and errno set to indicate the error.

ERRORS

The Fn posix_openpt function shall fail if:

Bq Er ENFILE

The system file table is full.

Bq Er EINVAL

The value of Fa oflag is not valid.

Bq Er EAGAIN

Out of pseudo-terminal resources.

SEE ALSO

pts(4), ptsname(3), tty(4)

STANDARDS

The Fn posix_openpt function conforms to St -p1003.1-2001 . The ability to use O_CLOEXEC is an extension to the standard.

HISTORY

The Fn posix_openpt function appeared in Fx 5.0 . In Fx 8.0 , this function was changed to a system call.

NOTES

The flag O_NOCTTY is included for compatibility; in Fx , opening a terminal does not cause it to become a process's controlling terminal.

AUTHORS

An Ed Schouten Aq ed@FreeBSD.org