stuff

Examples/ipc/ipcpipe2.c

@@ -0,0 +1,75 @@
+/*
+ * ipcpipe2.c - Pipes are unidirectional and require
+ *              two pipes to send data in two directions
+ */
+
+#include <sys/types.h> // needed for pid_t
+#include <sys/wait.h>  // needed for wait system call
+#include <unistd.h>    // needed for fork, read, write, close system calls
+#include <stdlib.h>    // needed for exit
+#include <stdio.h>     // needed for printf, perror
+
+int main()
+{
+    /* Create pipes */
+    int pipe_to_child[2];
+    if (pipe(pipe_to_child) == -1) {
+        printf("PIPE FAILURE\n");
+        exit(EXIT_FAILURE);
+    }
+    int pipe_from_child[2];
+    if (pipe(pipe_from_child) == -1) {
+        printf("PIPE FAILURE\n");
+        exit(EXIT_FAILURE);
+    }
+
+    pid_t pid = fork(); // fork into 2 processes
+
+    if (pid == -1) // error
+    {
+        perror("fork");
+        exit(EXIT_FAILURE);
+    }
+    else if (pid == 0) //
+    {
+        /* Close unused pipe ends */
+        close(pipe_to_child[1]);
+        close(pipe_from_child[0]);
+
+        /* Write to parent */
+        write(pipe_from_child[1], "CHELLO", 6);
+        close(pipe_from_child[1]);
+
+        /* Read from parent */
+        char data[32];
+        read(pipe_to_child[0], data, sizeof(data));
+        printf("Child received %s from parent\n", data);
+
+        /* Close pipe */
+        close(pipe_to_child[0]);
+
+        return 0; // Return success
+    }
+    else // parent
+    {
+        /* Close unused pipe ends */
+        close(pipe_to_child[0]);
+        close(pipe_from_child[1]);
+
+        /* Write to child */
+        write(pipe_to_child[1], "PHELLO", 6);
+        close(pipe_to_child[1]);
+
+        /* Read from child */
+        char data[32];
+        read(pipe_from_child[0], data, sizeof(data));
+        printf("Parent recieved %s from child\n", data);
+
+        /* Close pipe */
+        close(pipe_from_child[0]);
+
+        /* Wait for child */
+        wait(0);
+    }
+    return 0; // Return success
+}