/* Execute simultaneously with something like:
   while [ 1 ]; do kill -s USR1 13314; done
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include <signal.h>

int COUNTER; /* Weak symbol */

void sigHandler( int sig){
    printf("Process %d: Counter: %d (sigHandler())\n", getpid(), COUNTER); /* Unsafe */
    COUNTER--;
}

int main(){
    int i;

    printf("Process %d\n", getpid()); /*, Child's PID = %d\n", getpid(), pid); */
    fflush( stdout);
    COUNTER = 0;

    signal( SIGUSR1, sigHandler);

    while( 1){
        printf("Process %d: Counter: %d (main())\n", getpid(), COUNTER); /* Unsafe */
        COUNTER++;
    }

    exit(0);
}