NAME
ptm —
pseudo-terminal multiplexor
device
SYNOPSIS
pseudo-device pty
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[PATH_MAX];
char sn[PATH_MAX];
};
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.