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

int getPidd();

int main(int argc, char* argv[])
{
    printf("\tCommand Center\n");

    if(argc!=1)
    {
        printf("Program is working without parameters.\n");
        exit(1);
    }
    int target_pid;

    target_pid=getPidd();

    switch(kill(target_pid,SIGRTMIN+6))
    {
        case 0:
            printf("Signal send succesfully!\n");
            break;
        default:
            switch(errno)
            {
                case EINVAL:
                    printf("The value of the sig argument is an invalid or unsupported signal number\n");
                    break;
                case EPERM:
                    printf("The process does not have permission to send the signal to any receiving process\n");
                    break;
                case ERSCH:
                    printf("No process or process group can be found corresponding to that specified by pid\n");
                    break;
            }
            break;
    }
}

int getPidd()
{
    char target_pid[6];
    char *endint;
    int pid;
    while(1)
    {
        printf("Provide a PID:\n");
        scanf("%6s",target_pid);

        pid=strtol(target_pid,&endint,10);
        if(*endint || pid<=2 || pid==getpid())
        {
            printf("Incorrect PID!\n");
            continue;
        }
        else
        {
            printf("PID: %d\n",pid);
            break;
        }
    }
    return pid;
}