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PTY(4) Kernel Interfaces Manual PTY(4) NAME pty -- old-style compatibility pseudo-terminal driver SYNOPSIS device pty DESCRIPTION The pty driver provides support for the traditional BSD naming scheme that was used for accessing pseudo-terminals before it was replaced by pts(4). This traditional naming is still used in Linux. When the de- vice /dev/ptyXX is being opened, a new terminal shall be created with the pts(4) driver. A device node for this terminal shall be created, which has the name /dev/ttyXX. The pty driver also provides a cloning System V /dev/ptmx device. New code should not try to allocate pseudo-terminals using this inter- face. It is only provided for compatibility with older C libraries that tried to open such devices when posix_openpt(2) was being called, and for running Linux binaries. FILES The BSD-style compatibility pseudo-terminal driver uses the following device names: /dev/pty[l-sL-S][0-9a-v] Pseudo-terminal master devices. /dev/tty[l-sL-S][0-9a-v] Pseudo-terminal slave devices. /dev/ptmx Control device, returns a file descriptor to a new master pseudo-terminal when opened. DIAGNOSTICS None. SEE ALSO posix_openpt(2), pts(4), tty(4) HISTORY A pseudo-terminal driver appeared in 4.2BSD. BUGS Unlike previous implementations, the master and slave device nodes are destroyed when the PTY becomes unused. A call to stat(2) on a nonexis- tent master device will already cause a new master device node to be created. The master device can only be destroyed by opening and clos- ing it. The pty driver cannot be unloaded, because it cannot determine if it is being used. FreeBSD 14.3 October 28, 2019 PTY(4)
NAME | SYNOPSIS | DESCRIPTION | FILES | DIAGNOSTICS | SEE ALSO | HISTORY | BUGS
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