__declspec(noinline)
__declspec(noinline) tells the compiler to never inline a particular member function (function in a class).
It may be worthwhile to not inline a function if it is small and not critical to the performance of your code. That is, if the function is small and not likely to be called often, such as a function that handles an error condition.
Keep in mind that if a function is marked noinline, the calling function will be smaller and thus, itself a candidate for compiler inlining.