利用recv函数实现C++服务器接收数据

下面是一个简单的C++服务器端程序，利用recv函数接收数据：

#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>

int main() {
    // 创建socket
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd == -1) {
        std::cerr << "Error creating socket" << std::endl;
        return 1;
    }

    // 绑定端口
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(8888);

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        std::cerr << "Bind failed" << std::endl;
        return 1;
    }

    // 监听端口
    listen(server_fd, 3);

    // 接受连接
    int client_fd;
    struct sockaddr_in client_addr;
    int addr_len = sizeof(client_addr);
    client_fd = accept(server_fd, (struct sockaddr *)&client_addr, (socklen_t *)&addr_len);

    // 接收数据
    char buffer[1024] = {0};
    int valread = recv(client_fd, buffer, 1024, 0);
    
    std::cout << "Received: " << buffer << std::endl;

    return 0;
}

这个程序创建一个服务器端socket，绑定端口，监听端口，并接受连接。接受到连接后，利用recv函数从客户端接收数据，并输出到控制台。