I am trying to write a small program where I can send signals and then ask for an action to be triggered if that signal is received. For example, here is an example where I am trying to write a programme that will say you pressed ctrl*c when someone presses ctrl+c. My questions are what you would expect from a beginner so bear with me. First, how can I get ro test the functionality of my program? My udnerstanding is you get the process ID and then through kill -signalnumber PID you will be able to send the signal? For example kill -2 2345 to send teh SIGINT to PID 2345. But mine doesn't work. First I opened a new shell then used shellname & on the terminal to get the PID, then on the terminal wrote kill -2 2345 if the PID was that for example. But I always recieve '... No such process'. Where I am getting it wrong?
HI,
I need to handle SIGUSR2 signal in my application to change the state of the application dynamically. I have implemented the signal handler. However the application is able to catch only one SIGUSR2 signal. The second SIGUSR2 signal causes the application to crash. This is happning only with... (3 Replies)
Hi folks
I'm trying to write a signal handler (in c on HPUX) that will catch the child process launched by execl when it's finished so that I can check a compliance file.
The signal handler appears to catch the child process terminating however when the signal handler completes the parent... (3 Replies)
Guys,
I'm doing signal handling in Perl. I'm trying to catch ^C signal inside the script.
There two scripts : one shell script and one perl script.
The shell script calls the perl script.
For e.g. shell script a.sh and perl scipt sig.pl.
Shell script a.sh looks something like this :... (6 Replies)
Hello all,
I am starting to learn signal handling in Linux and have been trying out some simple codes to deal with SIGALRM. The code shown below sets a timer to count down. When the timer is finished a SIGALRM is produced. The handler for the signal just increments a variable called count. This... (7 Replies)
Hi,
I have a main loop which calls a sub loop, which finally returns to the main loop itself. The main loop runs when a flag is set. Now, I have a signal handler for SIGINT, which resets the flag and thus stops the main loop. Suppose I send SIGINT while the program is in subloop, I get an error... (1 Reply)
Hi guys,
this is my first posting, so at first hi to everyone! ;)
I have a problem with ucontext_t in connection with signal handling. I want to simulate a preemptive scheduler. I am using the iTimer with ITIMER_PROF, to schedule the interrupts. You find the code below:
#include <stdio.h>... (18 Replies)
i wrote handler for sigsegv such that i can allocate memory for a variable to which
sigsegv generated for illlegal acces of memory.
my code is
#include <signal.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
char *j;
void segv_handler(int dummy)
{
j=(char *)malloc(10);
... (4 Replies)
hi friends i have a problem in signal handling ...
let me explain my problem clearly..
i have four process ..
main process forks two child process and each child process again forks another new process respectively...
the problem is whenever i kill the child process it is reforking and the... (2 Replies)
Discussion started by: senvenugopal
2 Replies
LEARN ABOUT DEBIAN
signal
signal(3tcl)signal(3tcl)NAME
signal - dynamically loadable signal handling for Tcl/Tk
SYNOPSIS
signal (add|delete|print|version) [options]
COMMANDS
add signo proc [-async]
Adds a signal handler for signal signo through proc proc. Signals can be provided by number, or the most common ones are provided by name
(e.g., SIGHUP). The proc is any Tcl procedure, and it is evaluated when the signal comes in. It will be provided no arguments.
Signal handlers have Posix semantics - they persist until reset.
If -async is used, the signal handler is created using Tcl_AsyncCreate(). Checks for the signal are very frequent (each evaluation) using
this technique, but one doesn't know quite where evaluation is or how to handle errors in this situation. The code will evaluate the pro-
vided procedure in the current interpreter if available, and in the interpreter which added the signal handler otherwise. At least until a
better scheme is suggested.
The -async is especially useful to interrupt "runaway" procs, or to cause a quick exit; the default mechanism simply waits for another
MainLoop cycle.
signal delete signo
Restores handling of signal signo to the default ( SIG_DFL ).
signal print
Prints the handling of all signals with handlers. Formatted as
signal ----> procedure or as
signal !---> procedure
if the signal is handled asynchronously
signal print signo
Prints the procedure for handling signal signo. Prints the word UNHANDLED if no signal handler is active for that signal.
signal version
Returns the string representing the current version of the package
AUTHOR
Michael Schwartz <mschwart@nyx.net>. Tilman Kranz <tilde@tk-sls.de> patched this for wider portability on Linux
Tcl Signal Extension 1.4.0.1 Tcl signal(3tcl)