second question

server_2.c

+#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;
+}
+
+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);
+    }
+
+
+
+    while(running){
+        std::cout << "id: " << getpid() << std::endl;
+        std::cout << "father id: " << getppid() << std::endl;
+        std::cout << "groupd id: "  << getpgrp() << std::endl;
+        std::cout << rand() % 100 << std::endl;
+        sleep(1);
+    }
+    std::cout << "finished" << std::endl;
+
+    return EXIT_SUCCESS;
+}
+
+/*
+father id: 15834
+groupd id: 16168
+62
+^CReceived signal: 2
+Stopping the program
+finished
+
+using kill -s INT 17116 here is the result:
+
+46
+Received signal: 2
+Stopping the program
+finished
+
+now with only kill:
+
+id: 17828
+father id: 15834
+groupd id: 17828
+62
+[1]    17828 terminated  ./a.out
+
+
+after the change in the code:
+id: 18796
+father id: 15834
+groupd id: 18796
+90
+Received signal: 15
+Stopping the program
+finished
+~/workspace: 
+
+
+after -s KILL:
+
+id: 19282
+father id: 15834
+groupd id: 19282
+11
+[1]    19282 killed     ./a.out
+
+
+SIGKILL cannot be shown: https://stackoverflow.com/questions/35569659/the-signals-sigkill-and-sigstop-cannot-be-caught-blocked-or-ignored-why
+
+
+when I used kill without -s INT, nothing happened, but when I used it with -s INT, the first terminal got deleted
+
+It's not stopping with CTR+C, neither with kill, but I'm getting the signals
+With -s KILL it stopped
+
+
+groupd id: 22843
+86
+id: 22843
+father id: 16628
+groupd id: 22843
+77
+^CReceived signal: 2
+Stopping the program
+finished
+Message during exit
+
+
+I just saw that I forgot to add the perror() part
+
+With kill:
+
+21
+Received signal: 15
+Stopping the program
+finished
+Message during exit
+
+With kill -s KILL:
+
+id: 24595
+father id: 16628
+groupd id: 24595
+62
+[1]    24595 killed     ./a.out
+
+*/
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