Storing a 64-bit Value

To store a 64-bit pointer value, use ULONG_PTR. A ULONG_PTR value is 32 bits when compiled with a 32-bit compiler and 64 bits when compiled with a 64-bit compiler.

The following examples use real-world code that has been ported to 64-bit Windows. Commentary on the steps to make the code 64-bit compatible is included.

Example 1: Getting an Address

The following code illustrates a portable way to get an address.

ULONG getAnAddress( )
Int *somePointer
Return( (ULONG) somePointer );

ULONG_PTR getAnAddress( )
Int *somePointer
Return( (ULONG_PTR) somePointer );

Example 2: Calculating an Address

The following code illustrates a portable way to calculate an address.

Int *somePointer;
Int *someOtherPointer;
somePointer = (int *)( (ULONG)someOtherPointer + 0x20 );

Int *somePointer;
Int *someOtherPointer;
somePointer = (int *)( (ULONG_PTR)someOtherPointer + 0x20 );

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Build date: 6/25/2012