Hi there,

we have this C++ DLL we wrote some time ago to do some Win32 native
stuff for us.

The function we're calling in the DLL returns a boolean value (type
bool) indicating success of the operation.

We declare the import in C# like follows:

DllImport("xyz.dll")]
private static extern bool DoSomething(...);

We call the function like this:

bool result = DoSomething(...);

Now: we're using this in Visual Studio 2008. When we set the target
framework version to 2.0 everything works fine - the function returns
false, the result-variable has the value false.

As soon as we switch the target framework version to 3.5 (no other
changes to the project), the C++ function still returns false, but the
result-variable is set to true!

How could that be?

As a workaround we've change the result type from bool to int, returning
defined values for success or failure, but this is not very satisfactory...

Any advice?

Thanks
Thorsten