调用 WriteFile写数据时出错,用GetLastError得到错误代码为87(无效参数)。
代码片段如下:
if ((!WriteFile( m_hDevEx, pBuf, size, &WriteBytes, &Overlapped)) && (GetLastError() != ERROR_IO_PENDING)) { OutputDebugString("Write error\n"); return false; }
问题出在最后一个参数Overlapped,初始化是这样的:
OVERLAPPED Overlapped; Overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
这种初始化在ReadFile时时没有问题的,而WriteFile时需要将该结构体中的Offset,OffsetHigh两个参数设置成零,即:
OVERLAPPED Overlapped; Overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); Overlapped.Offset = 0; Overlapped.OffsetHigh = 0;
以上这样初始化之后,错误消失!
WriteFile操作时返回87错误
时间: 2024-10-09 04:34:01