How do C++ functions establish and close network connections in network programming?-C++-php.cn

In C network programming, establishing a network connection involves the following functions: socket(): Create a socket. connect(): Connect the socket to the remote host and port. To close a network connection, you need to use the close() function.

C++ 函数在网络编程中如何建立和关闭网络连接？

C function establishes and closes connections in network programming

In network programming, establishing and closing network connections is crucial important. C provides several functions for handling these operations.

Establishing a network connection

socket(): Create a socket for network communication.
connect(): Connect the socket to the remote host and port.

Code example: Establish TCP connection

#include  #include  int main() { // 创建套接字 int socket_fd = socket(AF_INET, SOCK_STREAM, 0); // 设置服务器地址信息 struct sockaddr_in server_addr; server_addr.sin_family = AF_INET; server_addr.sin_port = htons(8080); server_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); // 连接到服务器 connect(socket_fd, (struct sockaddr *) &server_addr, sizeof(server_addr)); // ... 继续执行其他操作 ... }

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Close network connection

close (): Close a socket.

Code example: Close TCP connection

#include  int main() { // ... 获取已连接的套接字 fd ... // 关闭套接字 close(socket_fd); }

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Practical case

Using the above function, you can easily Implement connection establishment and closing in network programming in C. For example, write a simple TCP client and server to demonstrate what these functions do.

Client code:

#include  #include  #include  int main() { // 创建套接字并连接到服务器 int socket_fd = socket(AF_INET, SOCK_STREAM, 0); struct sockaddr_in server_addr; server_addr.sin_family = AF_INET; server_addr.sin_port = htons(8080); server_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); connect(socket_fd, (struct sockaddr *) &server_addr, sizeof(server_addr)); // 发送数据到服务器 std::string msg = "Hello from client!"; send(socket_fd, msg.c_str(), msg.size(), 0); // 关闭连接 close(socket_fd); return 0; }

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Server code:

#include  #include  #include  int main() { // 创建套接字并绑定到端口 int socket_fd = socket(AF_INET, SOCK_STREAM, 0); struct sockaddr_in server_addr; server_addr.sin_family = AF_INET; server_addr.sin_port = htons(8080); server_addr.sin_addr.s_addr = INADDR_ANY; bind(socket_fd, (struct sockaddr *) &server_addr, sizeof(server_addr)); // 监听连接 listen(socket_fd, 5); // 接受连接 int client_socket_fd = accept(socket_fd, NULL, NULL); // 从客户端接收数据 char buffer[256]; recv(client_socket_fd, buffer, sizeof(buffer), 0); std::cout << "Received from client: " << buffer << std::endl; // 发送响应到客户端 std::string msg = "Hello from server!"; send(client_socket_fd, msg.c_str(), msg.size(), 0); // 关闭连接 close(client_socket_fd); close(socket_fd); return 0; }

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