GETPTY(3)                                                            GETPTY(3)


NAME
     _getpty, mkpts - get a PTY or Pseudo-TTY

SYNOPSIS
     #include <sys/types.h>
     #include <sys/stat.h>
     #include <unistd.h>
     #include <fcntl.h>

     char *_getpty(int *fildes, int oflag, mode_t mode,
                    int nofork);

DESCRIPTION
     This function finds and allocates a pair of devices making a pseudo-TTY,
     described in pty(7M).

     If filedes is not null, then the file descriptor for the master or
     controlling side of the pty is stored through the pointer.  If
     successful, a pointer to an internal, static area containing the name of
     the slave device node is returned.  The file descriptor is opened with
     the value oflag, constructed as described in open(2).

     The access bits of the slave device node are set to mode.  The owner of
     the slave device is set to the real UID of the caller, and the GID is
     reset.

     If nofork is 0 and the process does not have effective UID 0, then this
     function may execute /usr/sbin/mkpts to change the owner and permissions
     of the node for the slave device.

     The slave device file in /dev will be created if it does not already
     exist.

     This function may also use the facilities described in getgrent(3C) to
     set the group of the slave device node.

SEE ALSO
     chmod(2), chown(2), getgrent(3C), open(2), pty(7M), tty(1), tty(7)

DIAGNOSTICS
     A returned value of 0 indicates failure, with errno indicating the nature
     of the problem.

BUGS
     When _getpty(3) uses /usr/sbin/mkpts, it waits for it to finish with
     waitpid(2).  This requires that the caller not have set SIGCLD to
     SIG_IGN.  Instead, _getpty(3) should save and restore the signal handler.
     See wait(2) and signal(2).  The nofork argument can used to avoid
     undesirable forks.


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