scoketcan setsockopt用法

下面是一个使用 setsockopt 函数设置 SO_REUSEADDR 选项的例子：

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

int main() {
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1) {
        std::cerr << "Failed to create socket." << std::endl;
        return 1;
    }

    // 设置 SO_REUSEADDR 选项，允许在绑定端口时重用该端口
    int reuse = 1;
    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) == -1) {
        std::cerr << "Failed to set SO_REUSEADDR option." << std::endl;
        close(sockfd);
        return 1;
    }

    sockaddr_in server_address{};
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = INADDR_ANY;
    server_address.sin_port = htons(8080);

    if (bind(sockfd, reinterpret_cast<sockaddr *>(&server_address), sizeof(server_address)) == -1) {
        std::cerr << "Failed to bind socket." << std::endl;
        close(sockfd);
        return 1;
    }

    if (listen(sockfd, SOMAXCONN) == -1) {
        std::cerr << "Failed to listen on socket." << std::endl;
        close(sockfd);
        return 1;
    }

    std::cout << "Listening on port 8080..." << std::endl;

    while (true) {
        int client_sockfd = accept(sockfd, nullptr, nullptr);
        if (client_sockfd == -1) {
            std::cerr << "Failed to accept client connection." << std::endl;
            continue;
        }

        std::cout << "Accepted client connection." << std::endl;

        const char *message = "Hello, client!";
        if (send(client_sockfd, message, strlen(message), 0) < 0) {
            std::cerr << "Failed to send message to client." << std::endl;
        }

        close(client_sockfd);
    }

    close(sockfd);
    return 0;
}

在上面的例子中，我们先创建了一个套接字，然后使用 setsockopt 函数设置 SO_REUSEADDR 选项，允许在绑定端口时重用该端口。接下来绑定端口、监听连接请求，并在循环中接受客户端连接并向客户端发送数据。