I have problem compiling examples for catching a signal.

I get: no matching converting function 'handler' to type void (*) (int)
on sa.sa_handler = handler;

the same error happens for signal(sig,handler) method.

This is om a mandrake 9.1 and I use gcc with kdevelop.

Are linux signals not compatible with unix or is it any thing else?

Any idees?

Example:
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

/* Simple signal handler */
void handler(int sig) {
if (sig == SIGINT)
printf("got SIGINT\n");
else
printf("got SIGTSTP\n");
};

int main(void) {
struct sigaction sa;
struct sigaction oldint;

/* Initialize the sa structure */
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;

/* Set up the signal handlers; remember the old
handler for SIGINT so we can restore it later */
sigaction(SIGINT, &sa, &oldint);
sigaction(SIGTSTP, &sa, NULL);

/* Sleep for five seconds, or until a signal wakes
us up*/
sleep(5);

/* Restore the behavior of SIGINT just to show it can
be done. */
sigaction(SIGINT, &oldint, NULL);

return 0;
};

Why don't you use `signal ()' istead? Its more easy to use I think. Take a look at the man page.

Works perfectly copied - pasted from your post.
Compiled on Debian with gcc 3.3.

Ya, I am with Hko... I usually use the signal function not sigaction, but your code runs just fine on my machine with gcc version 3.3.2 20040119 (Gentoo Linux 3.3.2-r7, propolice-3.3-7).

I think the problem is kdevelop. I will try to compile in a shell.

signal() gives the same error.

Thanks!

Ok I solved the problem:

I tried to make the handler a class member function and it did not work. So I made a handler that calls a static function in my class since I only got one(desktop and WM).
It compiles but is it some design faults here?

I will use the signal() since all of you recommended it.

By the way. NICE spellchecker on this site.

My test prog.
catsig.h:

#ifndef CATSIG_H
#define CATSIG_H

class catsig {
public:
catsig();
~catsig();
static void amethod();
};

#endif

catsig.cpp:
catsig::catsig(){

struct sigaction sa;
struct sigaction oldint;

/* Initialize the sa structure */
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;

/* Set up the signal handlers; remember the old
handler for SIGINT so we can restore it later */
sigaction(SIGINT, &sa, &oldint);
sigaction(SIGTSTP, &sa, NULL);

/* Sleep for five seconds, or until a signal wakes
us up*/
sleep(5);

/* Restore the behavior of SIGINT just to show it can
be done. */
sigaction(SIGINT, &oldint, NULL);
}

catsig::~catsig(){}

void catsig::amethod(){}

sorry the handler did not join the code:

Here is the code:

catsig.h
class catsig
{
public:
catsig();
~catsig();
static void amethod();
};


catsig.cpp
#include "catsig.h"
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

/* Simple signal handler */
void handler(int sig)
{
if (sig == SIGINT)
printf("got SIGINT\n");
else
printf("got SIGTSTP\n");

catsig::amethod();
};

catsig::catsig()
{
struct sigaction sa;
struct sigaction oldint;

/* Initialize the sa structure */
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;

/* Set up the signal handlers; remember the old handler for SIGINT so we can restore it later */
sigaction(SIGINT, &sa, &oldint);
sigaction(SIGTSTP, &sa, NULL);

/* Sleep for five seconds, or until a signal wakes us up*/
sleep(5);

/* Restore the behavior of SIGINT just to show it can be done. */
sigaction(SIGINT, &oldint, NULL);
}

catsig::~catsig(){}

void catsig::amethod(){}