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

int main(int argc, char*argv[])
{
    int pid;
    if (argc <= 1) {
        printf("No PID given\n");
        return(1);
    } else if (argc > 2) {
        printf("Too many arguments\n");
        return(1);
    } else {
    long val;
        char *next;
    val = strtol(argv[1], &next, 10);
    if ((next == argv[1]) || (*next != '\0')) {
        printf("Argument '%s' is not a number\n", argv[1]);
        return(1);
    } else {
            pid = val;
    }
    }
    kill(pid, SIGUSR1);
    return(0);
}