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