signal doubt

[nnair]

Hi,
Given below is a sample pgm which I read in a book. Acc, to the book, this pgm should call function ‘abc’ the 1st time Ctrl^C is pressed & when Ctrl^C is pressed 2nd time it should terminate the pgm. But when I tried executing the same pgm in Linux, every time, Ctrl^C was pressed, the pgm called ‘abc’ function & went in infinite loop.
Could anyone tell me why did this happen & what is the default beavior?

#include<signal.h>

void abc();
main()
{
printf(“Press Key\n”);
signal(SIGINT,abc);
for(;;
}

void abc()
{
printf(“U have pressed the key”):
}

Thanx,
N

 

[MikeLacey]

Don't know a lot about signal handlers -- but don't you have to uninstall the handler as your first action *in* the handler? Mike

&quot;Experience is the comb that Nature gives us, after we are bald.&quot;

Is that a haiku?
I never could get the hang
of writing those things.

 

[mramo]

I think it depends on Unix implementation. In LINUX the handler keeps installed until you uninstall it by calling, for example, the sigignore(SIGINT) function, but in another Unix systems ( i have tried in HP-UX ) every time the signal is caught it is unistalled automatically and you must call again the signal function to maintain the handler active.