直接上代码
VOID CALLBACK test_io_completion_routine(
DWORD dwErrorCode,
DWORD dwNumberOfBytesTransfered,
LPOVERLAPPED lpOverlapped
)
{
printf("dwErrorCode %d, dwNumberOfBytesTransfered %d ", dwErrorCode, dwNumberOfBytesTransfered);
printf("%s ", (char*)(lpOverlapped + 1));
free(lpOverlapped);
}
BOOL
queue_read_req(
HANDLE hFile,
DWORD nNumberOfBytesToRead,
DWORD Offset)
{
BOOL bResult = FALSE;
OVERLAPPED* olv = (OVERLAPPED* )malloc(sizeof(OVERLAPPED) + nNumberOfBytesToRead);
if(olv)
{
DWORD nBytesRead = 0;
ZeroMemory(olv, sizeof(OVERLAPPED) + nNumberOfBytesToRead);
olv->Offset = Offset;
bResult = ReadFile(hFile, (void*)(olv + 1), nNumberOfBytesToRead, &nBytesRead, olv) ;
if (!bResult)
{
DWORD dwError = 0;
switch (dwError = GetLastError())
{
case ERROR_HANDLE_EOF:
free(olv);
break;
case ERROR_IO_PENDING:
break;
default:
break;
}
}
}
return bResult;
}
void test_io_port()
{
LPCWSTR FileTest = L"C:\NTDLL.txt";
HANDLE hFile = CreateFileW(FileTest, // file to open
GENERIC_READ, // open for reading
FILE_SHARE_READ, // share for reading
NULL, // default security
OPEN_EXISTING, // existing file only
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, // normal file
NULL); // no attr. template
if(hFile != INVALID_HANDLE_VALUE)
{
BindIoCompletionCallback(hFile, test_io_completion_routine, 0);
for(int i = 0; i < 5; i++)
{
queue_read_req(hFile, 1024, i*1024 );
}
Sleep(5000);
CloseHandle(hFile);
}
}