怎样获取成功发送了多少数据

[tanweijian2009]

用WriteFile()向并口发送数据后，调用什么函数能返回某个时刻成功发送多少呢

[tanweijian2009]

UP

[stjay]

BOOL WriteFile(
　　HANDLE hFile, // 文件句柄
　　LPCVOID lpBuffer, // 数据缓存区指针
　　DWORD nNumberOfBytesToWrite, // 你要写的字节数
　　LPDWORD lpNumberOfBytesWritten, // 用于保存实际写入字节数的存储区域的指针
　　LPOVERLAPPED lpOverlapped // OVERLAPPED结构体指针
　　);

阻塞模式：
*lpNumberOfBytesWritten就是发送字节

异步模式：
用，重叠IO
BOOL GetOverlappedResult(
HANDLE hFile,
LPOVERLAPPED lpOverlapped,
LPDWORD lpNumberOfBytesTransferred,
BOOL bWait
);
*lpNumberOfBytesTransferred为传送的字节
或完成端口
BOOL GetQueuedCompletionStatus(
HANDLE CompletionPort,
LPDWORD lpNumberOfBytes,
PULONG_PTR lpCompletionKey,
LPOVERLAPPED* lpOverlapped,
DWORD dwMilliseconds
);
*lpNumberOfBytes为传送字节

[tanweijian2009]

楼上的朋友能给个简单的例子吗，谢谢啦

[一条晚起的虫]

//同步方式
BYTE *lpBuffer;
DWORD nNumberOfBytesToWrite = 100; //需要写入100个数据
DWORD NumberOfBytesWritten; //返回实际写入的数据字节数
int rtn = WriteFile(hFile, lpBuffer, nNumberOfBytesToWrite, &NumberOfBytesWritten, NULL);
if(!rtn)
{
DWORD dwError = GetLastError(); //返回具体错误代码
}
else
{
TRACE("%d", NumberOfBytesWritten);
}