Signal for IPC

Signals/CMakeLists.txt

@@ -0,0 +1,23 @@
+# CMakeList.txt : CMake project for Signals, include source and define
+# project specific logic here.
+#
+cmake_minimum_required (VERSION 3.8)
+
+# Enable Hot Reload for MSVC compilers if supported.
+if (POLICY CMP0141)
+  cmake_policy(SET CMP0141 NEW)
+  set(CMAKE_MSVC_DEBUG_INFORMATION_FORMAT "$<IF:$<AND:$<C_COMPILER_ID:MSVC>,$<CXX_COMPILER_ID:MSVC>>,$<$<CONFIG:Debug,RelWithDebInfo>:EditAndContinue>,$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>>")
+endif()
+
+project(Signals VERSION 1.0.0 LANGUAGES C CXX)
+
+set(CMAKE_CXX_STANDARD          17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS        OFF)
+
+add_executable(SIGINT "ctrl_c.c")
+add_executable(RaiseSysCall "raise.c")
+add_executable(KillSender "kill_sender.c")
+add_executable(KillReceiver "kill_receiver.c")
+
+# TODO: Add tests and install targets if needed.

Signals/ctrl_c.c

@@ -0,0 +1,51 @@
+/*
+	Consider a program below, 
+	There is some special thing attached to SIGABRT signal.
+
+	You can see, in below code, line no 23 registers a handler routine with signal SIGABRT.
+	when abort() is called, it delivers the signal SIGABRT to this process, and  abort_signal_handler() will be invoked.
+	Note that, it is mandatory to terminate the process by calling exit(0) from abort_signal_handler(). Handler routine
+	for SIGABRT signal must not return to caller. It it returns, Kernel will kill the process instead. You can perform experiment
+	by removing the line 16 in below code, and you will notice that process is terminated after execution of abort_signal_handler().
+	Hence, Process either commit suicide or it will be killed by the OS. SIGABRT signal cannot be blocked(= ignore) by the process.
+
+*/
+
+
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static void
+ctrlC_signal_handler(int sig) {
+
+	printf("Ctrl-C pressed\n");
+	printf("Bye Bye\n");
+	exit(0);
+
+}
+
+static void
+abort_signal_handler(int sig) {
+
+	printf("process is aborted\n");
+	printf("Bye Bye\n");
+	exit(0);
+
+}
+
+int
+main(int argc, char* argv[]) {
+
+	signal(SIGINT, ctrlC_signal_handler);
+	signal(SIGABRT, abort_signal_handler);
+
+	char ch;
+	printf("About process (y/n) ?\n");
+	scanf("%c", &ch);
+	if (ch == 'y')
+		abort();
+
+
+	return 0;
+}

Signals/kill_receiver.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <signal.h>
+
+static void
+signal_handler(int sig) {
+
+	printf("Signal %d received\n", sig);
+
+}
+
+int
+main(int argc, char** argv) {
+
+	signal(SIGUSR1, signal_handler);
+	scanf("\n");
+	return 0;
+}

Signals/kill_sender.c

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+#include <stdio.h>
+#include <signal.h>
+
+
+int
+main(int argc, char** argv) {
+
+	kill(5827, SIGUSR1);
+	scanf("\n");
+	return 0;
+}

Signals/raise.c

@@ -0,0 +1,32 @@
+#include <signal.h>
+#include <stdio.h>
+
+void signal_catchfunc(int);
+
+int main() {
+
+	int ret;
+
+	ret = signal(SIGINT, signal_catchfunc);
+
+	if (ret == SIG_ERR) {
+		printf("Error: unable to set signal handler.\n");
+		exit(0);
+	}
+
+	printf("Going to raise a signal\n");
+	ret = raise(SIGINT);
+	if (ret != 0) {
+		printf("Error: unable to raise SIGINT signal.\n");
+		exit(0);
+	}
+
+	printf("Exiting...\n");
+	return 0;
+}
+
+void signal_catchfunc(int signal) {
+
+	printf("!! signal caught !!\n");
+
+}