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$FreeBSD: releng/10.2/share/man/man4/pty.4 213573 2010-10-08 12:40:16Z uqs $
.Dd August 20, 2008 .Dt PTY 4 .Os .Sh NAME .Nm pty .Nd BSD-style and System V-style compatibility pseudo-terminal driver .Sh SYNOPSIS .Cd "device pty" .Sh DESCRIPTION The .Nm driver provides support for the traditional BSD naming scheme that was used for accessing pseudo-terminals. When the device
a /dev/ptyXX is being opened, a new terminal shall be created with the .Xr pts 4 driver. A device node for this terminal shall be created, which has the name
p The .Nm driver also provides a cloning System V
p New code should not try to allocate pseudo-terminals using this interface. It is only provided for compatibility with older C libraries that tried to open such devices when .Xr posix_openpt 2 was being called. .Sh FILES The BSD-style compatibility pseudo-terminal driver uses the following device names: l -tag -width ".Pa /dev/pty[l-sL-S][0-9a-v]" t Pa /dev/pty[l-sL-S][0-9a-v] Pseudo-terminal master devices. t Pa /dev/tty[l-sL-S][0-9a-v] Pseudo-terminal slave devices. t Pa /dev/ptmx Control device, returns a file descriptor to a new master pseudo-terminal when opened. .El .Sh DIAGNOSTICS None. .Sh SEE ALSO .Xr posix_openpt 2 , .Xr pts 4 , .Xr tty 4 .Sh HISTORY A pseudo-terminal driver appeared in x 4.2 . .Sh BUGS Unlike previous implementations, the master and slave device nodes are destroyed when the PTY becomes unused. A call to .Xr stat 2 on a nonexistent master device will already cause a new master device node to be created. The master device can only be destroyed by opening and closing it.
p The .Nm driver cannot be unloaded, because it cannot determine if it is being used.