stuff

Examples/ipc/ipcsignal.c

@@ -0,0 +1,46 @@
+/*
+ * ipcsignal.c - Shows how to use the kill system call
+ *               to send a signal from one process to another
+ */
+
+#include <sys/types.h> // needed for pid_t
+#include <sys/wait.h>  // needed for wait system call
+#include <unistd.h>    // needed for fork, getpid, getppid, kill system calls
+#include <stdlib.h>    // needed for exit
+#include <signal.h>    // needed for signal system call
+#include <stdio.h>     // needed for printf, perror
+
+void signal_handler(int sig)
+{
+    pid_t pid = getpid();
+    printf("Process %d received signal %d\n", pid, sig);
+}
+
+int main()
+{
+    // Set a signal handler for a user defined signal number 1
+    signal(SIGUSR1, signal_handler);
+
+    pid_t pid = fork(); // fork into 2 processes
+
+    if(pid < 0) // error
+    {
+        perror("fork");
+        exit(EXIT_FAILURE);
+    }
+    else if(pid == 0) // child
+    {
+        // Send a signal to the parent by its PID
+        pid_t parent_pid = getppid();
+        printf("Sending SIGUSR1(%d) to %d\n", SIGUSR1, parent_pid);
+        kill(parent_pid, SIGUSR1);
+
+        return 0; // Return success
+    }
+    else // parent
+    {
+        // Wait for child
+        wait(0);
+    }
+    return 0; // Return success
+}