server.c

Example for linux,hope you like it

#include "client.h"
#include <ctype.h>

int main()
{
    int server_fifo_fd, client_fifo_fd;
    struct data_to_pass_st my_data;
    int read_res;
    char client_fifo[256];
    char *tmp_char_ptr;

    mkfifo(SERVER_FIFO_NAME, 0777);
    server_fifo_fd = open(SERVER_FIFO_NAME, O_RDONLY);
    if (server_fifo_fd == -1) {
        fprintf(stderr, "Server fifo failure\n");
        exit(EXIT_FAILURE);
    }

    sleep(10); /* lets clients queue for demo purposes */

    do {
        read_res = read(server_fifo_fd, &my_data, sizeof(my_data));
        if (read_res > 0) {

// In this next stage, we perform some processing on the data just read from the client.
// We convert all the characters in some_data to uppercase and combine the CLIENT_FIFO_NAME
// with the received client_pid.

            tmp_char_ptr = my_data.some_data;
            while (*tmp_char_ptr) {
                *tmp_char_ptr = toupper(*tmp_char_ptr);
                tmp_char_ptr++;
            }
            sprintf(client_fifo, CLIENT_FIFO_NAME, my_data.client_pid);

// Then we send the processed data back, opening the client pipe in write-only, blocking mode.
// Finally, we shut down the server FIFO by closing the file and then unlinking the FIFO.

            client_fifo_fd = open(client_fifo, O_WRONLY);
            if (client_fifo_fd != -1) {
                write(client_fifo_fd, &my_data, sizeof(my_data));
                close(client_fifo_fd);
            }
        }
    } while (read_res > 0);
    close(server_fifo_fd);
    unlink(SERVER_FIFO_NAME);
    exit(EXIT_SUCCESS);
}