Resetting 8087CW in C++ causing exception in .NET application

Question

I am working with a .NET 3.5 application in C# that calls some legacy C++ code regularly. I've noticed that calling into the C++ sometimes leads to an "Overflow or underflow arithmetic operation" when I mouse over an Infragistics UltraGrid that has a dropdown list. I've discovered that this only happens when the C++ codes does the following:

Word SavedWord = Default8087CW;
Set8087CW(0x133f); // Disable all fpu exceptions

...

Set8087CW(SavedWord);

If I comment out the last line, I no longer get the error in my .NET application. I haven't noticed any other side effects in the rest of the application. As a quick fix, I would like to leave this line commented out. What are the consequences of disabling FPU exceptions and not resetting the control word?

Answer 1

The solution is found here: "StackOverFlowException in WPF when call method from C++ library".

Thanks to Hans Passant for this.

Answer 2

After testing on other machines, it appears that commenting out the Set8087CW(SavedWord); line only fixes the issue on my machine. There appears to be a bug in my version of Infragistics (8.2.20082.2204). Rolling back to 8.2.20082.1000 fixed the issue.