For some reason, I can't do this


Code:
ULARGE_INTEGER lpTotalBytesUsed, lpTotalNumberOfBytes, lpTotalNumberOfFreeBytes;

lpTotalBytesUsed = lpTotalNumberOfBytes - lpTotalNumberOfFreeBytes;
I get this:

--------------------Configuration: PieGraph - Win32 Debug--------------------
Compiling...
PIEGRAPH.cpp
C:\Windows\Desktop\Matt\Win32 C++\Chapt 5\PieGraph\PIEGRAPH.cpp(97) : error C2676: binary '-' : 'union _ULARGE_INTEGER' does not define this operator or a conversion to a type acceptable to the predefined operator
Error executing cl.exe.

PieGraph.exe - 1 error(s), 0 warning(s)

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Any Ideas?