Where is pointer metadata stored?

Could be that I am overlooking something obvious, but where is pointer metadata stored? For instance if I have a 32-bit int pointer ptr and I execute ptr++ it knows to advance 4 bytes in memory. However, if I have a 64-bit int pointer it knows to advance 8 bytes. S开发者_StackOverflowo who keeps track of what type of pointer ptr is and where is it stored? For simplicity you can limit this to C++.

It isn't stored anywhere, per-se. The compiler looks at the type of the ptr and turns the ++ operation into an increment of the correct number of bytes.

In the symbol table while the compiler runs. Nowhere while your program runs, or rather it is implicit in the lower level code produced by the compiler.

It's not stored anywhere, it's determined at compile time. In fact, take this code as an example:

int *abc = NULL;
cout << abc + 1; /* Prints sizeof(int) */
cout << (void *)((char *)abc + 1); /* Prints 1. Casting it back to void * is necessary,
           otherwise it will try to dereference it and print as a string. */