c - I am generating signal and facing the strange behaviour -

i have started getting hands of signals in linux here strange behavior happening in code. have started , searched have not found anything, sorry if question lame, here code-

void handler(int sig ){     printf("inside handler\n"); }  int main(int argc, char * argv[], char * envp[]){     if( signal(sigint, handler) ==sig_err )         exit(exit_failure);      for(size_t = 0; ; i++){         printf("%d\n", i);         sleep(2);     } } 

i know printf, signal calls not idea use have not studied sigaction till now. according book , others tutorial if press ctrl+c has call handler every time here strange thing: when pressing ctrl+c once, it's calling handler next time it's terminating program. why strange thing happening?

the manual page signal syscall says:

if signal signum delivered process, 1 of following happens:

• if disposition set sig_ign, signal ignored.

• if disposition set sig_dfl, default action associated signal (see signal(7)) occurs.

• if disposition set function, then first either disposition reset sig_dfl, or signal blocked (see portability below), , handler called argument signum. if invocation of handler caused signal blocked, signal unblocked upon return handler.

since default behavior of sigint terminate once signal reset default behavior, subsequent behavior different.