accept函数使用例子

下面是一个使用accept函数的例子：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define PORT 8080
#define MAX_CONNECTIONS 5

int main() {
    int server_socket, new_socket, valread;
    struct sockaddr_in address;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};
    const char *hello = "Hello from server!";
    
    // Create socket
    if ((server_socket = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("Failed to create socket");
        exit(EXIT_FAILURE);
    }
    
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

    // Bind socket to port
    if (bind(server_socket, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("Failed to bind socket");
        exit(EXIT_FAILURE);
    }
    
    // Listen for connections
    if (listen(server_socket, MAX_CONNECTIONS) < 0) {
        perror("Failed to listen for connections");
        exit(EXIT_FAILURE);
    }
    
    printf("Server is listening on port %d\n", PORT);
    
    // Accept incoming connections
    if ((new_socket = accept(server_socket, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
        perror("Failed to accept connection");
        exit(EXIT_FAILURE);
    }
    
    printf("New connection established\n");
    
    // Send message to client
    send(new_socket, hello, strlen(hello), 0);
    printf("Hello message sent\n");
    
    // Receive message from client
    valread = read(new_socket, buffer, 1024);
    printf("%s\n", buffer);
    
    return 0;
}

这个例子创建一个TCP服务器，监听指定的端口，等待客户端连接。当一个客户端连接成功后，使用accept函数接受连接，建立一个新的socket用于与客户端通信。随后，服务器向客户端发送一条消息，接收客户端的回复，并打印出来。