Windows 的 TransmitFile 函数使得可以在不需要经由应用程序的缓冲区的情况下，将文件数据从磁盘发送到网络。然而，使用 Winsock 完成数据传输时，无法直接使用 TransmitFile 函数，因为它要求使用 SOCKET 套接字。下面的示例代码演示了如何使用 TransmitFile 函数通过 Winsock 发送数据。

#define FILENAME "file.txt"
#define PORT "5000"
#define IP "127.0.0.1"

// 初始化 Winsock 库
WSADATA wsa;
if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) {
    printf("WSAStartup failed with error: %d\n", GetLastError());
    return 1;
}

// 创建 socket
SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET) {
    printf("Failed to create socket with error: %d\n", WSAGetLastError());
    return 1;
}

// 填写服务器地址信息
struct sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(atoi(PORT));
serverAddr.sin_addr.s_addr = inet_addr(IP);

// 连接服务器
if (connect(sock, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
    printf("connect failed with error: %d\n", WSAGetLastError());
    closesocket(sock);
    WSACleanup();
    return 1;
}

// 发送文件
HANDLE hFile = CreateFileA(FILENAME, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
if (hFile == INVALID_HANDLE_VALUE) {
    printf("Failed to open file with error: %d\n", GetLastError());
    return 1;
}

SOCKET filesock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, 0);
if (filesock == INVALID_SOCKET) {
    printf("Failed to create file socket with error: %d\n", WSAGetLastError());
    CloseHandle(hFile);
    return 1;
}

if (