PTM(4)							   BSD Kernel Interfaces Manual 						    PTM(4)

NAME

     ptm -- pseudo-terminal multiplexor device

SYNOPSIS

     pseudo-device pty [count]

DESCRIPTION

     The ptm driver is the backend for the /dev/ptm device.  It supports three ioctl(2)s.  The first is TIOCPTMGET, which allocates a free pseudo-
     terminal device, sets its user ID to the calling user, revoke(2)s it, and returns the opened file descriptors for both the master and the
     slave pseudo-terminal device to the caller in a struct ptmget.  This struct has the following content:

	   struct ptmget {
		   int	   cfd;
		   int	   sfd;
		   char    cn[16];
		   char    sn[16];
	   };

     where cfd and sfd contain the master resp. slave device's file descriptor and cn and sn the corresponding paths in the file system.

     The /dev/ptmx device supports two more ioctl(2)s, TIOCGRANTPT, which is used by grantpt(3), TIOCPTSNAME, which is used by ptsname(3).

     The ptm device is included with the pseudo-device pty(4).	It can be disabled by adding ``options NO_DEV_PTM'' to the kernel configuration.

FILES

     /dev/ptm			       ptm access device

     /dev/ptmx			       ptm cloning device, used to implement Unix98 ptys

SEE ALSO

     grantpt(3), openpty(3), posix_openpt(3), ptsname(3), unlockpt(3), pty(4)

HISTORY

     The /dev/ptm device appeared in OpenBSD 3.5 and was ported to NetBSD 3.0.

BSD
								 November 12, 2005							       BSD