XtVaGetValues() returns incorrect information on 64 bit platforms (38829)

When I call XtVaGetValues() on an XRT widget to retrieve a resource value, and then I use that returned value in calculations, I find that the value I'm retrieving is incorrect. It can be 0, or can be some completely random numbers. What's the problem?

Ensure that the variables to which you retrieve the values in the XtVaGetValues() call are of the correct type. Please reference the Programmer's Guide and Reference Manual for the XRT product you are using to ensure the type is correct. If you are using the wrong type, you may not have noticed any problems under 32 bit, but depending on your 64 bit architecture, some variable types are different sizes, and could be incorrect now.