client.c

《Beginning Linux Programming》书的配置实例源代码。

// Here's the client, client.c. The first part of this program opens the server FIFO,
// if it already exists, as a file. It then gets its own process ID, which forms some
// of the data that will be sent to the server. The client FIFO is created, ready for
// the next section.

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

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

    server_fifo_fd = open(SERVER_FIFO_NAME, O_WRONLY);
    if (server_fifo_fd == -1) {
        fprintf(stderr, "Sorry, no server\n");
        exit(EXIT_FAILURE);
    }

    my_data.client_pid = getpid();
    sprintf(client_fifo, CLIENT_FIFO_NAME, my_data.client_pid);
    if (mkfifo(client_fifo, 0777) == -1) {
        fprintf(stderr, "Sorry, can't make %s\n", client_fifo);
        exit(EXIT_FAILURE);
    }

// For each of the five loops, the client data is sent to the server.
// Then the client FIFO is opened (read-only, blocking mode) and the data read back.
// Finally, the server FIFO is closed and the client FIFO removed from memory.

    for (times_to_send = 0; times_to_send < 5; times_to_send++) {
        sprintf(my_data.some_data, "Hello from %d", my_data.client_pid); 
        printf("%d sent %s, ", my_data.client_pid, my_data.some_data);
        write(server_fifo_fd, &my_data, sizeof(my_data));
        client_fifo_fd = open(client_fifo, O_RDONLY);
        if (client_fifo_fd != -1) {
            if (read(client_fifo_fd, &my_data, sizeof(my_data)) > 0) {
                printf("received: %s\n", my_data.some_data);
            }
            close(client_fifo_fd);
        }
    }
    close(server_fifo_fd);
    unlink(client_fifo);
    exit(EXIT_SUCCESS);
}