21a.c

/*
============================================================================
Name : 21a
Author : Piyush Singh
Description : Write two programs so that both can communicate by FIFO -Use two way communications.
Date: 21th Sep, 2025.
============================================================================
*/

// Before we are about to run the program we will be first creating a 2 fifo
// mkfifo fifo_A_to_B
// mkfifo fifo_B_to_A

// Program A: Client — sends message to server and waits for reply

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

int main() 
{
    const char *fifo_out = "fifo_A_to_B"; // Client → Server
    const char *fifo_in  = "fifo_B_to_A"; // Server → Client

    char send_msg[] = "👋 Hello Server, this is Client!";
    char recv_buffer[100];

    // Open FIFOs
    int fd_out = open(fifo_out, O_WRONLY);
    int fd_in  = open(fifo_in, O_RDONLY);

    if (fd_out == -1 || fd_in == -1) 
    {
        perror("❌ Client failed to open FIFOs");
        exit(1);
    }

    // Send message to server
    write(fd_out, send_msg, strlen(send_msg));
    printf("📤 Client sent: %s\n", send_msg);

    // Read reply from server
    ssize_t bytes_read = read(fd_in, recv_buffer, sizeof(recv_buffer));
    if (bytes_read > 0) 
    {
        recv_buffer[bytes_read] = '\0';
        printf("📥 Client received: %s\n", recv_buffer);
    }

    close(fd_out);
    close(fd_in);
    return 0;
}

/*
Output:
╰─ ./21a                                                                      ─╯
📤 Client sent: 👋 Hello Server, this is Client!
📥 Client received: 🤝 Hello Client, message received!
*/