Signal and alarm function

Question

I require some assistance or advice in a C programming task that I received... The task is that with the alarm(sec) a signal SIGALRM needs to be called. I have to increase a long int number in 1 second and print out on the screen how many times the number was increased in that time. I suspect that it will have to go with the alarm(1); I have the loop to increase the number ... bit have absolutely no idea on how to stop it after 1 second especially with the signal(SIGALRM,xxx) Shall I paste in the code that I have ?

#include <stdio.h> 
#include <unistd.h> 
#include <signal.h> 

int loop_function() { 
    int counter = 1; 
    long int n = 1; 
    while(n!=0) { 
        ++counter; 
        n++; 
        printf("%d: %d\n",counter,n); 
    } 
} 

int main() { 
   loop_function();
}

Answer 1

Probably, this is what you are looking for.

#include<stdio.h>
#include<signal.h>
#include<unistd.h>

void sigalrm_handler(int);
int loop_function();

static int counter = 1;
static long int n = 1;

int main()
{
    signal(SIGALRM, sigalrm_handler);
    //This will set the alarm for the first time.
    //Subsequent alarms will be set from sigalrm_handler() function
    alarm(1);

    printf("Inside main\n");

    while(1)
    {
        loop_function();
    }
    return(0);
}

void sigalrm_handler(int sig)
{
    printf("inside alarm signal handler\n");
    printf("%d: %d\n",counter,n);
    //exit(1);
    alarm(1);
}

int loop_function()
{
        ++counter;
        n++;
}