C++ - User aborts - exiting normally?

[Tobias Oed]

Darko M. wrote:

> Hello.
>
> I want to permit exiting without executing the object destructors. If a
> user kills the process, by CTRL-C etc., the process ends abnormaly without
> executing the proper destructors.

You want the destructors called or not? Anyway, I have no idea about how to
achieve this, I'll just comment on your jumping stuff.

> Now, I tried making a signal handler like this:
> void signal_routine(int SIG)
> {
> if (SIG==2 || SIG==3 || SIG==6 || SIG==15)
> exit();
> }
> , in hope that the "exit()" will make the programme exit properly.
> Unfortunately, it didn't work. I figured out that the exit() would
> make it work if called from within the main() function. So, I wrote a code
> like this:
>
> jmp_buf env;
> int signal_routine(int SIG);
> main()
> {
> signal(2, signal_routine);
> /* ... other signals' catchers ... */
> /* ... programme code ... */
> if (setjmp(env)!=0)
> exit();
> return 0;
> }
> int signal_routine(int SIG)
> {
> if (/* appropriate signal */)
> longjmp(env, 128);
> , if (/* other signals */)
> /* ... */
> }
>
> But, here's the problem: setjmp() needs to be executed once before the
> longjmp() jumps to the location. Now I got desperate so I ended with two

Are afraid of a race? The signal gets delivered before main reaches setjump?
Can't you simply install the signal handlers after calling setjmp?
Something like,

int main(void){
if(setjmp(env)!=0){
exit();
}else{
signal(....);
}
}

btw, there are macros in one of the standard headers (signal.h I think) that
look much better than those ugly numbers you use (and are also portable).

> unconditional jumps, where the first one jumps from the beginning of the
> programme to the execution of setjmp() and the second from the setjmp()
> back to the beginning of the programme. A little bit annoying, isn't it?

longjump is ugly, and what you suggest is a nightmare :(
good luck anyhow!
Tobias.

--
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[Darko M.]

Hello.

I want to permit exiting without executing the object destructors. If a
user kills the process, by CTRL-C etc., the process ends abnormaly without
executing the proper destructors.

Now, I tried making a signal handler like this:
void signal_routine(int SIG)
{
if (SIG==2 || SIG==3 || SIG==6 || SIG==15)
exit();
}
, in hope that the "exit()" will make the programme exit properly.
Unfortunately, it didn't work. I figured out that the exit() would
make it work if called from within the main() function. So, I wrote a code
like this:

jmp_buf env;
int signal_routine(int SIG);
main()
{
signal(2, signal_routine);
/* ... other signals' catchers ... */
/* ... programme code ... */
if (setjmp(env)!=0)
exit();
return 0;
}
int signal_routine(int SIG)
{
if (/* appropriate signal */)
longjmp(env, 128);
, if (/* other signals */)
/* ... */
}

But, here's the problem: setjmp() needs to be executed once before the
longjmp() jumps to the location. Now I got desperate so I ended with two
unconditional jumps, where the first one jumps from the beginning of the
programme to the execution of setjmp() and the second from the setjmp()
back to the beginning of the programme. A little bit annoying, isn't it? And
it doesn't work properly, yet!

Now, I'm sorry if I protracted the topic, but I wonder if you have a
better solution to this simple problem?

Thanks, in advance.

Darko M.

[Fletcher Glenn]

"Darko M." wrote:

>
> Hello.
>
> I want to permit exiting without executing the object destructors. If a
> user kills the process, by CTRL-C etc., the process ends abnormaly without
> executing the proper destructors.
>
> Now, I tried making a signal handler like this:
> void signal_routine(int SIG)
> {
> if (SIG==2 || SIG==3 || SIG==6 || SIG==15)
> exit();
> }
> , in hope that the "exit()" will make the programme exit properly.
> Unfortunately, it didn't work. I figured out that the exit() would
> make it work if called from within the main() function. So, I wrote a code
> like this:
>
> jmp_buf env;
> int signal_routine(int SIG);
> main()
> {
> signal(2, signal_routine);
> /* ... other signals' catchers ... */
> /* ... programme code ... */
> if (setjmp(env)!=0)
> exit();
> return 0;
> }
> int signal_routine(int SIG)
> {
> if (/* appropriate signal */)
> longjmp(env, 128);
> , if (/* other signals */)
> /* ... */
> }
>
> But, here's the problem: setjmp() needs to be executed once before the
> longjmp() jumps to the location. Now I got desperate so I ended with two
> unconditional jumps, where the first one jumps from the beginning of the
> programme to the execution of setjmp() and the second from the setjmp()
> back to the beginning of the programme. A little bit annoying, isn't it? And
> it doesn't work properly, yet!
>
> Now, I'm sorry if I protracted the topic, but I wonder if you have a
> better solution to this simple problem?
>
> Thanks, in advance.
>
> Darko M.

C++ exception handling is supposed to remove the need
for setjmp/longjmp.

What is wrong with the following?

main()
{
try
{
your code here
}
catch(signal_exception)
{
exit(whatever);
}
}

signal_handler()
{
throw signal_exception;
}

--
Fletcher Glenn
email [email]f-g-l-e-n-n@quest.com[/email] (remove the dashes)

[nal]

i think the fuction _exit() exits without calling the destructors.