Man Forkpty en anglais
OPENPTY(3)                 Linux Programmer's Manual                OPENPTY(3)



 

NAME


       openpty, login_tty, forkpty - tty utility functions

 

SYNOPSIS


       #include   /* for openpty and forkpty */
       #include  /* 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);

       Link with -lutil.

 

DESCRIPTION






       The  openpty()  function finds an available pseudo-terminal 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-terminal as returned by
       openpty()) by creating a new session, making fd the controlling  termi-
       nal  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-terminal.  The file descrip-
       tor of the master side of the pseudo-terminal 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-terminal.

 

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.

 

NOTES


       These functions are included in  libutil,  hence  you'll  need  to  add
       -lutil to your compiler command line.

       In  versions of glibc before 2.0.92, openpty() returns file descriptors
       for a BSD pseudo-terminal pair; since glibc 2.0.92, it  first  attempts
       to open a Unix 98 pseudo-terminal pair, and falls back to opening a BSD
       pseudo-terminal pair if that fails.

 

CONFORMING TO


       These are BSD functions, present in libc5 and glibc2.

 

BUGS


       Nobody knows how much space should be reserved for name.   So,  calling
       openpty() or forkpty() with non-NULL name may not be secure.

 

SEE ALSO


       fork(2), pty(7)



BSD                               2003-07-18                        OPENPTY(3)