The __declspec(noinline) attribute suppresses the inlining of a function at the call points of the function.

__declspec(noinline) can also be applied to constant data, to prevent the compiler from using the value for optimization purposes, without affecting its placement in the object. This is a feature that can be used for patchable constants, that is, data that is later patched to a different value. It is an error to try to use such constants in a context where a constant value is required. For example, an array dimension.

/* Prevent y being used for optimization */
__declspec(noinline) const int y = 5;
/* Suppress inlining of foo() wherever foo() is called */ 
__declspec(noinline) int foo(void);