c++设置udp套接字发送和接收缓存区大小

在 C++ 中设置 UDP 套接字发送和接收缓冲区大小可以使用 `setsockopt()` 函数来实现。下面是设置发送缓存区大小和接收缓存区大小的示例代码：

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

using namespace std;

int main()
{
    int sockfd = socket(AF_INET, SOCK_DGRAM, 0);

    if (sockfd < 0) {
        cerr << "Error opening socket" << endl;
        return 1;
    }

    // 设置发送缓存区大小
    int sendbuf = 1024 * 1024; // 1MB
    if (setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, &sendbuf, sizeof(sendbuf)) == -1) {
        cerr << "Error setting send buffer size" << endl;
        return 1;
    }

    // 设置接收缓存区大小
    int recvbuf = 1024 * 1024; // 1MB
    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &recvbuf, sizeof(recvbuf)) == -1) {
        cerr << "Error setting receive buffer size" << endl;
        return 1;
    }

    // 输出设置后的缓存区大小
    int sendbuf_new, recvbuf_new;
    socklen_t len = sizeof(sendbuf_new);
    if (getsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, &sendbuf_new, &len) == -1) {
        cerr << "Error getting send buffer size" << endl;
        return 1;
    }
    cout << "Send buffer size: " << sendbuf_new << endl;

    len = sizeof(recvbuf_new);
    if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &recvbuf_new, &len) == -1) {
        cerr << "Error getting receive buffer size" << endl;
        return 1;
    }
    cout << "Receive buffer size: " << recvbuf_new << endl;

    close(sockfd);

    return 0;
}

在上面的示例代码中，我们首先创建了一个 UDP 套接字，并设置了发送缓存区大小和接收缓存区大小为 1MB。然后，我们使用 `getsockopt()` 函数获取了设置后的缓存区大小，并输出结果。