#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>

void handler(int signum)
{
    if (signum == SIGUSR1)
    {
        FILE *fp;
        fp = fopen("test.txt", "w");
        fprintf(fp, "coucou, je suis bien en vie!\n");
        fclose(fp);
    }
    else if (signum == SIGUSR2)
    {
        exit(EXIT_SUCCESS);
    }
    else
    {
        printf("received signal %d\n", signum);
    }
}

int main(void)
{
    if (signal(SIGUSR1, handler) == SIG_ERR)
        printf("can't catch SIGUSR1\n");
    if (signal(SIGUSR2, handler) == SIG_ERR)
        printf("can't catch SIGUSR2\n");
    for (;;)
        pause();
}