openpty3

Usage

#include <pty.h>

Library

System utilities library (libutil, -lutil)

Overview

The openpty() function finds an available pseudoterminal and returns file descriptors for the master and slave in amaster and aslave. If name is not NULL, the filename of the slave is returned in name. If termp is not NULL, the terminal parameters of the slave will be set to the values in termp. If winp is not NULL, the window size of the slave will be set to the values in winp.

The login_tty() function prepares for a login on the terminal referred to by the file descriptor fd (which may be a real terminal device, or the slave of a pseudoterminal as returned by openpty()) by creating a new session, making fd the controlling terminal for the calling process, setting fd to be the standard input, output, and error streams of the current process, and closing fd.

The forkpty() function combines openpty(), fork(2), and login_tty() to create a new process operating in a pseudoterminal. A file descriptor referring to master side of the pseudoterminal is returned in amaster. If name is not NULL, the buffer it points to is used to return the filename of the slave. The termp and winp arguments, if not NULL, will determine the terminal attributes and window size of the slave side of the pseudoterminal.

Return value

If a call to openpty(), login_tty(), or forkpty() is not successful, -1 is returned and errno is set to indicate the error. Otherwise, openpty(), login_tty(), and the child process of forkpty() return 0, and the parent process of forkpty() returns the process ID of the child process.

Errors

openpty() fails if:

ENOENT

There are no available terminals.

login_tty() fails if ioctl(2) fails to set fd to the controlling terminal of the calling process.

forkpty() fails if either openpty() or fork(2) fails.

Attributes

For an explanation of the terms used in this section, see attributes(7).