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Diffstat (limited to 'man7/pty.7')
| -rw-r--r-- | man7/pty.7 | 65 |
1 files changed, 34 insertions, 31 deletions
diff --git a/man7/pty.7 b/man7/pty.7 index ecc1a6bec6..e8b6c95391 100644 --- a/man7/pty.7 +++ b/man7/pty.7 @@ -26,36 +26,39 @@ .SH NAME pty \- pseudoterminal interfaces .SH DESCRIPTION -A pseudoterminal (sometimes abbreviated "pty") +A pseudoterminal (sometimes abbreviated "pty") device pair is a pair of virtual character devices that provide a bidirectional communication channel. One end of the channel is called the -.IR master ; +.IR "pseudoterminal device" ; the other end is called the -.IR slave . +.IR "terminal device" . .PP -The slave end of the pseudoterminal provides an interface +The terminal end of the device pair provides an interface that behaves exactly like a classical terminal. -A process that expects to be connected to a terminal, -can open the slave end of a pseudoterminal and -then be driven by a program that has opened the master end. -Anything that is written on the master end is provided to the process -on the slave end as though it was input typed on a terminal. +A process that expects to be connected to a terminal +can open the terminal end of a pseudoterminal device pair and +then be driven by a program that has opened the pseudoterminal end +of the device pair. +Anything that is written on the pseudoterminal end is provided to the process +on the terminal end as though it was input typed on a terminal. For example, writing the interrupt character (usually control-C) -to the master device would cause an interrupt signal +to the pseudoterminal end of the device pair would cause an interrupt signal .RB ( SIGINT ) to be generated for the foreground process group -that is connected to the slave. -Conversely, anything that is written to the slave end of the -pseudoterminal can be read by the process that is connected to -the master end. +that is connected to the terminal end. +Conversely, anything that is written to the terminal end of the +device pair can be read by the process that is connected to +the pseudoterminal end. .PP -Data flow between master and slave is handled asynchronously, +Data flow between the two ends of the device pair is handled asynchronously, much like data flow with a physical terminal. -Data written to the slave will be available at the master promptly, +Data written to the terminal end will be available at +the pseudoterminal end promptly, but may not be available immediately. Similarly, there may be a small processing delay between -a write to the master, and the effect being visible at the slave. +a write to the pseudoterminal end, +and the effect being visible at the terminal end. .PP Historically, two pseudoterminal APIs have evolved: BSD and System V. SUSv1 standardized a pseudoterminal API based on the System V API, @@ -75,18 +78,18 @@ option. that option is disabled by default in the mainline kernel.) UNIX 98 pseudoterminals should be used in new applications. .SS UNIX 98 pseudoterminals -An unused UNIX 98 pseudoterminal master is opened by calling +An unused UNIX 98 pseudoterminal device is opened by calling .BR posix_openpt (3). -(This function opens the master clone device, +(This function opens the pseudoterminal multiplexor device, .IR /dev/ptmx ; see .BR pts (4).) After performing any program-specific initializations, -changing the ownership and permissions of the slave device using +changing the ownership and permissions of the terminal device using .BR grantpt (3), -and unlocking the slave using +and unlocking the terminal using .BR unlockpt (3)), -the corresponding slave device can be opened by passing +the corresponding terminal device can be opened by passing the name returned by .BR ptsname (3) in a call to @@ -110,9 +113,9 @@ For further details on these two files, see BSD-style pseudoterminals are provided as precreated pairs, with names of the form .I /dev/ptyXY -(master) and +(pseudoterminal) and .I /dev/ttyXY -(slave), +(corresponding terminal), where X is a letter from the 16-character set [p\-za\-e], and Y is a letter from the 16-character set [0\-9a\-f]. (The precise range of letters in these two sets varies across UNIX @@ -124,22 +127,22 @@ and constitute a BSD pseudoterminal pair. A process finds an unused pseudoterminal pair by trying to .BR open (2) -each pseudoterminal master until an open succeeds. -The corresponding pseudoterminal slave (substitute "tty" -for "pty" in the name of the master) can then be opened. +each pseudoterminal device until an open succeeds. +The corresponding terminal device (substitute "tty" +for "pty" in the name of the pseudoterminal device) can then be opened. .SH FILES .TP .I /dev/ptmx -UNIX 98 master clone device +UNIX 98 pseudoterminal multiplexor device .TP .I /dev/pts/* -UNIX 98 slave devices +UNIX 98 terminal devices .TP .I /dev/pty[p\-za\-e][0\-9a\-f] -BSD master devices +The BSD pseudoterminal devices .TP .I /dev/tty[p\-za\-e][0\-9a\-f] -BSD slave devices +The corresponding BSD terminal devices .SH NOTES Pseudoterminals are used by applications such as network login services .RB ( ssh "(1), " rlogin "(1), " telnet (1)), |