核心是使用socket API实现TCP通信，服务端依次创建套接字、绑定、监听、接受连接并收发数据，客户端则连接后发送消息并接收响应，需注意跨平台差异与错误处理。
想快速上手 C++ Socket 编程？其实核心就是使用操作系统提供的 socket API，通过创建套接字、绑定地址、监听连接（服务端）或发起连接（客户端），实现网络通信。下面以 TCP 为例，给出一个简单但完整的 C++ 网络通信实例，包含服务端和客户端代码，适用于 Linux 和 Windows（稍作调整）。
服务端代码：接收客户端消息并回传
服务端负责监听指定端口，等待客户端连接，收到数据后原样返回。
Linux / macOS 版本（g++ 编译）：
#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
int main() {
int server_fd, new_socket;
struct sockaddr_in address;
int addrlen = sizeof(address);
char buffer[1024] = {0};
// 创建套接字
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}
// 配置地址结构
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);
// 绑定
if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
// 监听
if (listen(server_fd, 3) < 0) {
perror("listen");
exit(EXIT_FAILURE);
}
std::cout << "Server listening on port 8080...\n";
// 接受连接
if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0) {
perror("accept");
exit(EXIT_FAILURE);
}
// 读取客户端消息
read(new_socket, buffer, 1024);
std::cout << "Client: " << buffer << "\n";
// 回传消息
const char *response = "Hello from server";
send(new_socket, response, strlen(response), 0);
std::cout << "Response sent\n";
close(new_socket);
close(server_fd);
return 0;
}
Windows 版本需包含 Winsock：
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#include <iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#pragma comment(lib, "ws2_32.lib")
int main() {
WSADATA wsa;
SOCKET server_fd, new_socket;
struct sockaddr_in address;
int addrlen = sizeof(address);
char buffer[1024] = {0};
if (WSAStartup(MAKEWORD(2,2), &wsa) != 0) {
std::cerr << "WSAStartup failed\n";
return 1;
}
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
std::cerr << "Socket creation error\n";
WSACleanup();
return 1;
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);
if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) == SOCKET_ERROR) {
std::cerr << "Bind failed\n";
closesocket(server_fd);
WSACleanup();
return 1;
}
if (listen(server_fd, 3) == SOCKET_ERROR) {
std::cerr << "Listen failed\n";
closesocket(server_fd);
WSACleanup();
return 1;
}
std::cout << "Server listening on port 8080...\n";
if ((new_socket = accept(server_fd, (struct sockaddr *)&address, &addrlen)) == INVALID_SOCKET) {
std::cerr << "Accept failed\n";
closesocket(server_fd);
WSACleanup();
return 1;
}
recv(new_socket, buffer, 1024, 0);
std::cout << "Client: " << buffer << "\n";
const char *response = "Hello from server";
send(new_socket, response, strlen(response), 0);
std::cout << "Response sent\n";
closesocket(new_socket);
closesocket(server_fd);
WSACleanup();
return 0;
}
客户端代码：连接服务端并发送消息
客户端主动连接服务端，发送一条消息，并接收响应。
Linux / macOS 客户端：
#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
int main() {
int sock = 0;
struct sockaddr_in serv_addr;
char *hello = "Hello from client";
char buffer[1024] = {0};
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
std::cerr << "Socket creation error\n";
return -1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(8080);
// 将 IP 地址从文本转换为二进制
if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
std::cerr << "Invalid address / Address not supported\n";
return -1;
}
if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
std::cerr << "Connection Failed\n";
return -1;
}
send(sock, hello, strlen(hello), 0);
std::cout << "Message sent to server\n";
read(sock, buffer, 1024);
std::cout << "Server response: " << buffer << "\n";
close(sock);
return 0;
}
Windows 客户端： 同样需要初始化 Winsock，其余逻辑一致，把 socket、connect、send、recv 替换为 Windows 对应函数即可。
编译与运行（Linux 示例）
保存服务端代码为 server.cpp，客户端为 client.cpp。
g++ server.cpp -o server g++ client.cpp -o client
终端1运行服务端：./server
终端2运行客户端：./client
观察输出，确认通信成功。
关键点说明
- AF_INET 表示 IPv4 协议族，SOCK_STREAM 表示 TCP 流式套接字。
- 服务端依次调用 socket → bind → listen → accept。
- 客户端调用 socket → connect → send/recv。
- 注意错误检查，真实项目中不能忽略返回值。
- 跨平台开发建议封装接口，或使用 Boost.Asio 等库简化操作。
