Differences between current version and previous revision of ProcessGroup.
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| Newer page: | version 11 | Last edited on Tuesday, September 4, 2007 6:09:44 pm | by BenStaz | |
| Older page: | version 10 | Last edited on Tuesday, September 4, 2007 5:50:31 pm | by BenStaz | Revert |
@@ -10,16 +10,30 @@
!Background Process Groups
* A background process does not have read access to the terminal.
* If a background process attempts to read from its controlling terminal its process group will be sent a [SIGTTIN].
+
+!Example
+
+Notice that cat, sort and uniq all have the same PGID (Process Group ID).
+<verbatim>
+staz@tokra:~/log$ cat results | sort | uniq & ps -jf
+[1] 1239
+UID PID PPID PGID SID C STIME TTY TIME CMD
+staz 1237 28341 1237 28341 0 17:55 pts/6 00:00:00 cat results
+staz 1238 28341 1237 28341 0 17:55 pts/6 00:00:00 sort
+staz 1239 28341 1237 28341 0 17:55 pts/6 00:00:00 uniq
+</verbatim>
The [TIOCGPGRP] and [TIOCSPGRP] calls described in termios(4) are used to get/set the process group of the control terminal.
If a ProcessGroup has a ControllingTerminal, [CLOCAL] is not set and a hangup occurs, then the ProcessGroup is sent a [SIGHUP].
If a ProcessGroup Leader exits, all children processes are sent a [SIGHUP]
If the exit of the process causes a process group to become orphaned, and if any member of the newly-orphaned process group is stopped, then a [SIGHUP] signal followed by a [SIGCONT] signal will be sent to each process in the newly-orphaned process group.
+
+
!! See Also
* ProcessRelationships
