View Source: Signal - Waikato Linux Users Group

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A signal is basically a message sent from one process to another, indicating a change of state.

Different versions of [Unix] use different names and/or numbers for some of the lesser used signals. See the signal(7) man-page. You can find the signals and numbers used in the [POSIX] standard, in <tt>/usr/include/bits/signum.h</tt> on a [Linux] system, or by invoking <tt>kill -l</tt>.

# [SIGHUP]
# [SIGINT]
# [SIGQUIT]
# [SIGILL]
# [SIGTRAP]
# [SIGABRT] (aka [SIGIOT])
# [SIGBUS]
# [SIGFPE]
# [SIGKILL]
# [SIGUSR1]
# [SIGSEGV]
# [SIGUSR2]
# [SIGPIPE]
# [SIGALRM]
# [SIGTERM]
# [SIGSTKFLT]
# [SIGCHLD]
# [SIGCONT]
# [SIGSTOP]
# [SIGTSTP]
# [SIGTTIN]
# [SIGTTOU]
# [SIGURG]
# [SIGXCPU]
# [SIGXFSZ]
# [SIGVTALRM]
# [SIGPROF]
# [SIGWINCH]
# [SIGIO]
# [SIGPWR]
# [SIGSYS]

!Hotkeys for some of the above symbols.

These hotkeys can be found by typing:

*stty -a

intr = ^C; quit = ^\; susp = ^Z
<verbatim>
intr = [SIGINT]
quit = [SIGQUIT]
susp = [SIGSTOP]
</verbatim>

Some people have a misconception that CTRL-S and CTRL-Q send a [SIGSTOP] and [SIGCONT] signal respectively.

This is not the case!

CTRL-S and CTRL-Q are used to control the flow of output to the terminal. CTRL-S tells the system not to send any more data to the screen until a CTRL-Q is pressed. You can use these to control fast scrolling output.

Here are a couple of pages that show how to code for signals:<br>
http://users.actcom.co.il/~choo/lupg/tutorials/signals/signals-programming.html<br>
http://www.gnu.org/software/libc/manual/html_node/Signal-Handling.html

5 pages link to Signal:

Last edited on Thursday, April 16, 2009 6:03:00 am by "AndreasFerber"

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