c - Custom SIGINT signal handler - Program still terminates even after signal is caught -

i playing signal.h , unistd.h libraries, , having issues. in code below, when send sigint signal running program calling ctrl-c, signal caught. however, when pressing ctrl-c again, program terminates. understand it, print statement "received signal 2" should printed every time press ctrl-c.

is understanding of signal incorrect, or there bug in code?

thanks input!

#include "handle_signals.h"   void sig_handler(int signum) {     printf("\nreceived signal %d\n", signum); }  int main() {     signal(sigint, sig_handler);     while(1)     {         sleep(1);     }     return 0; } 

terminal output:

xxx@ubuntu:~/dropbox/xxx/handle_signals$ ./handle_signals  ^c received signal 2 ^c xxx@ubuntu:~/dropbox/xxx/handle_signals$  

edit: here header i've included

#include <stdio.h> #include <stdlib.h> #include <signal.h> #include <unistd.h>   void sig_handler(int signum); 

thanks responses. reading through them now!

don't use signal, use sigaction:

the behavior of signal() varies across unix versions, , has varied historically across different versions of linux. avoid use: use sigaction(2) instead.

http://man7.org/linux/man-pages/man2/signal.2.html

in original unix systems, when handler established using signal() invoked delivery of signal, disposition of signal reset sig_dfl, , system did not block delivery of further instances of signal.

linux implements same semantics: handler reset when signal delivered.