Question

I have a chunk of code where it appears that a variable is changing at the end of a pre-processor block of code.

int initialKeyCount; #if(DEBUG) //          int initialKeyCount = _root.CountAllKeys();       initialKeyCount = 20000; #endif       currNode = currNode.EnsureDegreeKeysPresent(parent); //initialKeyCount = 19969 here #if(DEBUG)       int currentKeyCount = _root.CountAllKeys();       Debug.Assert(initialKeyCount == currentKeyCount,                string.Format('EnsureDegreeNodesPresent changed the node count from {0} to {1}.', initialKeyCount, currentKeyCount)); #endif 

When executing this in the debugger initialKeyCount = 19969 after supposedly assigning 20000. I have played around with this a bit and found that assignment to initialKeyCount is correct inside the first pre-processor block, but as soon as the code leaves the first pre-processor block the value magically changes to 19969.

This behavior is the same regardless of whether the variable is declared inside or outside the first pre-processor block. The value remains 19969 inside the second pre-processor block.

Are assignments made in a pre-processor block undefined outside of that block? That seems wrong but appears to be what is happening here.

Answer 1

Sounds like Visual Studio got confused. Try these steps in order

1. Use the Clean command
2. Restart Visual Studio
3. Delete every DLL and EXE that even remotely looks like your program
4. Double check every BIN and OBJ folder to see if you missed anything.
5. Search your whole hard drive for any DLL and EXE that even remotely looks like your program and delete them too

I used to see this once a week at an IT company I worked for. It usually happens when you have multiple copies of the same project, but I’ve seen it even without that.