Which bits of this are required? There are a couple of typo's in your code sample, no semi-colon after AcquireFastMutex and no closing curly bracket.
The underlining is being caused by the curly brackets inside the class, VA is not expecting these. Simplifying this down, VA is confused by:
class Xxx
{
{
void ExAcquireFastMutex();
}
}
which is understandable, since this does not actually compile.
Interestingly enough this does not compile either:
class Xxx
{
#pragma warning(suppress:28167)
{
void ExAcquireFastMutex();
}
}
I am using VS2005 and compiling this as C++. Are you actually compiling this as C++? Or as some other language?
I do not recognise PREfast and do not know anything about it.