UDP套接字编程在C中，printf在调用recvfrom()后不能工作？

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define BUF_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in server_addr, client_addr;
    char buffer[BUF_SIZE];
    socklen_t addr_len = sizeof(client_addr);

    // 创建UDP套接字
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 绑定套接字
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(12345);

    if (bind(sockfd, (const struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    // 接收数据
    if (recvfrom(sockfd, buffer, BUF_SIZE, 0, (struct sockaddr *)&client_addr, &addr_len) < 0) {
        perror("recvfrom failed");
        exit(EXIT_FAILURE);
    }

    // 处理数据
    // 这里可以根据需要对接收到的数据进行处理

    // 使用printf()函数打印数据
    printf("Received message: %s\n", buffer);

    // 关闭套接字
    close(sockfd);

    return 0;
}