How can I/O priority of a process be increased?

Question

I want to increase the I/O priority of a process. Answers for both .NET and Windows Vista would be nice. processexplorer is ok as well.

Answer 1

Be sure to align FILE_IO_PRIORITY_HINT_INFO structure properly when calling SetFileInformationByHandle.

Otherwise, you will get a ERROR_NOACCESS (error 998, 0x000003E6).

_declspec(align(8)) FILE_IO_PRIORITY_HINT_INFO priorityHint;
priorityHint.PriorityHint = IoPriorityHintLow;

BOOL ret = SetFileInformationByHandle(hFile, FileIoPriorityHintInfo, &priorityHint, sizeof(FILE_IO_PRIORITY_HINT_INFO));
DWORD err = GetLastError();