c++ setsockopt怎樣設置接收緩沖區

在C++中，使用setsockopt()函數可以設置套接字的選項

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

int main() {
    int sockfd;
    struct sockaddr_in server_addr;
    int recv_buffer_size = 4096; // 設置接收緩沖區大小為4KB

    // 創建套接字
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        std::cerr << "Error creating socket" << std::endl;
        return 1;
    }

    // 配置服務器地址
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(8080);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    // 連接到服務器
    if (connect(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
        std::cerr << "Error connecting to server" << std::endl;
        return 1;
    }

    // 設置接收緩沖區大小
    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &recv_buffer_size, sizeof(recv_buffer_size)) == -1) {
        std::cerr << "Error setting receive buffer size" << std::endl;
        return 1;
    }

    std::cout << "Receive buffer size set to " << recv_buffer_size << " bytes" << std::endl;

    // 接收數據
    char buffer[recv_buffer_size];
    ssize_t received = recv(sockfd, buffer, recv_buffer_size, 0);
    if (received == -1) {
        std::cerr << "Error receiving data" << std::endl;
        return 1;
    }

    std::cout << "Received " << received << " bytes: " << std::string(buffer, received) << std::endl;

    // 關閉套接字
    close(sockfd);

    return 0;
}

在這個示例中，我們首先創建了一個套接字，然后配置了服務器地址。接下來，我們使用setsockopt()函數設置了接收緩沖區的大小。最后，我們接收了一些數據并打印出來。