C System Programming: POSIX System Calls, Processes & IPC Masterclass

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/wait.h>

int main(void) {
    int pipefd[2]; // pipefd[0] = read, pipefd[1] = write
    if (pipe(pipefd) == -1) { perror("pipe"); return 1; }

    pid_t pid = fork();
    if (pid < 0) { perror("fork"); return 1; }

    if (pid == 0) { // CHILD PROCESS
        close(pipefd[1]); // Close unused write end
        char buffer[128];
        ssize_t bytesRead = read(pipefd[0], buffer, sizeof(buffer) - 1);
        if (bytesRead > 0) {
            buffer[bytesRead] = '\0';
            printf("[Child Received]: %s\n", buffer);
        }
        close(pipefd[0]);
        exit(0);
    } else { // PARENT PROCESS
        close(pipefd[0]); // Close unused read end
        const char *msg = "Hello from Parent Process!";
        write(pipefd[1], msg, strlen(msg));
        close(pipefd[1]);
        wait(NULL); // Wait for child to exit
        printf("[Parent]: Child finished execution.\n");
    }
    return 0;
}