int main(int argc, char** argv){
     ...
    fileFd=open(...)
    signal(SIGUSR1, signalHandler)
    ...
}


void signalHandler(int signo){
    switch(signo){

    case SIGUSR1:
        myExit(EXIT_FAILURE);
        break;

    default:
        break;

    }
}

void myExit(int ret){

    ...DO STUFF...
    close(fileFd);
    exit(ret);

}