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PTS(4) Kernel Interfaces Manual PTS(4) NAME pts -- pseudo-terminal driver DESCRIPTION The pts driver provides support for a device-pair termed a pseudo-terminal. A pseudo-terminal is a pair of character devices, a master device and a slave device. The slave device provides to a process an interface identical to that described in tty(4). However, whereas all other devices which provide the interface described in tty(4) have a hardware device of some sort behind them, the slave de- vice has, instead, another process manipulating it through the master half of the pseudo-terminal. That is, anything written on the master device is given to the slave device as input and anything written on the slave device is presented as input on the master device. The following ioctl(2) calls apply only to pseudo-terminals: TIOCPKT Enable/disable packet mode. Packet mode is enabled by specifying (by reference) a nonzero parameter and dis- abled by specifying (by reference) a zero parameter. When applied to the master side of a pseudo-terminal, each subsequent read(2) from the terminal will return data written on the slave part of the pseudo-terminal preceded by a zero byte (symbolically defined as TIOCPKT_DATA), or a single byte reflecting control status information. In the latter case, the byte is an inclu- sive-or of zero or more of the bits: TIOCPKT_FLUSHREAD whenever the read queue for the ter- minal is flushed. TIOCPKT_FLUSHWRITE whenever the write queue for the ter- minal is flushed. TIOCPKT_STOP whenever output to the terminal is stopped a la `^S'. TIOCPKT_START whenever output to the terminal is restarted. TIOCPKT_DOSTOP whenever VSTOP is `^S' and VSTART is `^Q'. TIOCPKT_NOSTOP whenever the start and stop charac- ters are not `^S/^Q'. While this mode is in use, the presence of control status information to be read from the master side may be de- tected by a select(2) for exceptional conditions. This mode is used by rlogin(1) and rlogind(8) to imple- ment a remote-echoed, locally `^S/^Q' flow-controlled re- mote login with proper back-flushing of output; it can be used by other similar programs. TIOCGPTN Obtain device unit number, which can be used to generate the filename of the pseudo-terminal slave device. This ioctl(2) should not be used directly. Instead, the ptsname(3) function should be used. TIOCPTMASTER Determine whether the file descriptor is pointing to a pseudo-terminal master device. This ioctl(2) should not be used directly. It is used to implement routines like grantpt(3). FILES The files used by this pseudo-terminals implementation are: /dev/pts/[num] Pseudo-terminal slave devices. DIAGNOSTICS None. SEE ALSO posix_openpt(2), grantpt(3), ptsname(3), pty(4), tty(4) HISTORY A pseudo-terminal driver appeared in 4.2BSD. In FreeBSD 8.0, it was replaced with the pts driver. FreeBSD 14.3 August 20, 2008 PTS(4)
NAME | DESCRIPTION | FILES | DIAGNOSTICS | SEE ALSO | HISTORY
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