If I'm understanding correctly, you're saying a compiler will optimize out "void*" to instead be the value put into it, so theres no pointer dereference to get to it?
That's what I am talking about. I don't know much about modern C optimizations.
That's what I am talking about. I don't know much about modern C optimizations.
What can be measureable though is function call overhead - if you write a sort function that takes a function pointer and your sort function calls that, there is a lot of work for saving the local state, preparing all the arguments for the function, etc. That work can potentially be avoided if the compiler can inline the function call into (a copy of) your sort function.
Lets say it's 4 8bit ints. It can be sequentially and directly in memory like:
stack: [0x01, 0x02, 0x03, 0x03]
stack: [0x07002412, 0x0700241A, 0x07002424, 0x070036A0]
heap (or stack, really):
0x07002412: 0x01
0x0700241A: 0x02
0x07002424: 0x03
0x070036A0: 0x04
That is what "void*" is doing. You're using a pointer instead of a value.
In C# this is what generics allow you to avoid.
// This is like my first memory layout above.
struct Foo<T> { public T MyField; }
// This is like the second layout above.
struct Foo { public object MyField; }