openpty(3) [freebsd man page]

PTY(3)							   BSD Library Functions Manual 						    PTY(3)

NAME

     openpty, forkpty -- auxiliary functions to obtain a pseudo-terminal

LIBRARY

     System Utilities Library (libutil, -lutil)

SYNOPSIS

     #include <sys/types.h>
     #include <sys/ioctl.h>
     #include <termios.h>
     #include <libutil.h>

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

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

DESCRIPTION

     The function openpty() attempts to obtain the next available pseudo-terminal from the system (see pty(4)).  If it successfully finds one, it
     subsequently changes the ownership of the slave device to the real UID of the current process, the group membership to the group ``tty'' (if
     such a group exists in the system), the access permissions for reading and writing by the owner, and for writing by the group, and invali-
     dates any current use of the line by calling revoke(2).

     If the argument name is not NULL, openpty() copies the pathname of the slave pty to this area.  The caller is responsible for allocating the
     required space in this array.

     If the arguments termp or winp are not NULL, openpty() initializes the termios and window size settings from the structures these arguments
     point to, respectively.

     Upon return, the open file descriptors for the master and slave side of the pty are returned in the locations pointed to by amaster and
     aslave, respectively.

     The forkpty() function first calls openpty() to obtain the next available pseudo-terminal from the system.  Upon success, it forks off a new
     process.  In the child process, it closes the descriptor for the master side of the pty, and calls login_tty(3) for the slave pty.  In the
     parent process, it closes the descriptor for the slave side of the pty.  The arguments amaster, name, termp, and winp have the same meaning
     as described for openpty().

RETURN VALUES

     The openpty() function returns 0 on success, or -1 on failure.

     The forkpty() function returns -1 on failure, 0 in the slave process, and the process ID of the slave process in the parent process.

ERRORS

     The openpty() function may fail and set the global variable errno for any of the errors specified for the grantpt(3), posix_openpt(3),
     ptsname(3), and unlockpt(3) functions and the revoke(2) system call.

     In addition to this, forkpty() may set it to any value as described for fork(2).

SEE ALSO

     chmod(2), chown(2), fork(2), getuid(2), open(2), revoke(2), login_tty(3), pty(4), termios(4), group(5)

BSD
								 December 29, 1996							       BSD

Check Out this Related Man Page

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)

Linux and UNIX Man Pages

openpty(3) [freebsd man page]

Check Out this Related Man Page