OPENPTY(3)						     Linux Programmer's Manual							OPENPTY(3)

NAME

       openpty, login_tty, forkpty - tty utility functions

SYNOPSIS

       #include <pty.h>  /* for openpty and forkpty */
       #include <utmp.h> /* for login_tty */

       int openpty(int *amaster, int *aslave, char *name, struct termios *termp, struct winsize * winp);

       int login_tty(int fd);

       pid_t forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp);

DESCRIPTION

       The  openpty() function finds an available pseudo-tty 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 tty fd (which may be a real tty device, or the slave of a pseudo-tty as returned by
       openpty()) by creating a new session, making fd the controlling terminal for the current process, setting fd to be the standard input, out-
       put, and error streams of the current process, and closing fd.

       The  forkpty() function combines openpty(), fork(), and login_tty() to create a new process operating in a pseudo-tty.  The file descriptor
       of the master side of the pseudo-tty is returned in amaster, and the filename of the slave in name if it is not NULL.  The termp  and  winp
       parameters, if not NULL, will determine the terminal attributes and window size of the slave side of the pseudo-tty.

RETURN VALUES

       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() will fail if:

       ENOENT There are no available ttys.

       login_pty() will fail if ioctl() fails to set fd to the controlling terminal of the current process.

       forkpty() will fail if either openpty() or fork() fails.

FILES

       /dev/[pt]ty[pqrstuwxyzabcdePQRST][0123456789abcdef]

CONFORMING TO

       These are BSD functions, present in libc5 and glibc2.

SEE ALSO

       fork(2)

BSD MANPAGE
							    2001-12-13								OPENPTY(3)