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#include <iostream>
#include <csignal>
#include <cstdlib>
#include <unistd.h>
#include <cstring>
#include <unistd.h>
volatile bool running = true;
void print_in_exit() {
std::cout << "Message during exit" << std::endl;
}
void handle_signal(int signal_number) {
std::cout << "Received signal: " << signal_number << std::endl;
std::cout << "Stopping the program" << std::endl;
running = false;
}
void print_process_info(const char* process_type) {
std::cout <<process_type << " | id: " << getpid() << std::endl;
std::cout <<process_type << " | father id: " << getppid() << std::endl;
std::cout <<process_type << " | groupd id: " << getpgrp() << std::endl;
std::cout << rand() % 100 << std::endl;
}
int main(){
std::cout << "started" << std::endl;
if (atexit(print_in_exit) != 0) {
perror("Fail in exit");
exit(EXIT_FAILURE);
}
struct sigaction sa;
sa.sa_handler = handle_signal;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGINT, &sa, nullptr) == -1) {
perror("Fail in exit");
exit(EXIT_FAILURE);
}
if (sigaction(SIGTERM, &sa, nullptr) == -1) {
perror("Fail in exit");
exit(EXIT_FAILURE);
}
pid_t pid = fork();
if (pid == 0) {
while (running) {
print_process_info("Child");
sleep(1);
}
} else {
while (running) {
print_process_info("Parent");
sleep(1);
}
}
std::cout << "finished" << std::endl;
return EXIT_SUCCESS;
}
/*
Ouput:
Parent | id: 26677
Parent | father id: 16628
Parent | groupd id: 26677
23
Child | id: 26678
Child | father id: 26677
Child | groupd id: 26677
23
Parent | id: 26677
Parent | father id: 16628
Parent | groupd id: 26677
67
Child | id: 26678
Child | father id: 26677
Child | groupd id: 26677
67
Parent | id: 26677
Parent | father id: 16628
Parent | groupd id: 26677
35
Child | id: 26678
Child | father id: 26677
Child | groupd id: 26677
35
Parent | id: 26677
Parent | father id: 16628
Parent | groupd id: 26677
29
Child | id: 26678
Child | father id: 26677
Child | groupd id: 26677
29
Parent | id: 26677
Parent | father id: 16628
Parent | groupd id: 26677
2
Child | id: 26678
Child | father id: 26677
Child | groupd id: 26677
2
^CReceived signal: 2
Received signal: 2
Stopping the program
Stopping the program
finished
finished
Message during exit
Message during exit
They have the same group id, and they both stop cin CTR+C because they belong to the same group,
and this singal is sent to all the process in the group
*/