sigusr.c

#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
volatile sig_atomic_t n_sigusr1 = 0;

static void sig_handler(int);

int main(int argc, char *argv[])
{

    if (signal(SIGUSR1, sig_handler) == SIG_ERR)
    {
        perror("signal");
        exit(EXIT_FAILURE);
    }

    while ((n_sigusr1) < 5)
    {
        // vide
    }

    printf("Fin du processus\n");
    printf("Reçu %d SIGUSR1\n", n_sigusr1);
    return (EXIT_SUCCESS);
}

static void sig_handler(int signum)
{

    if (signum == SIGUSR1)
    {
        n_sigusr1++;
    }
    else
    {
        char *msg = "Reçu signal inattendu\n";
        write(STDERR_FILENO, msg, strlen(msg));
        _exit(EXIT_FAILURE);
    }
}