Originally Posted by
Narue 
>seem it is trick question.
It is a trick question. Not only can the size of a pointer vary depending on the system, the size of pointers to different types aren't required to be the same. The best answer to this question would be sizeof p , where p is defined as the pointer one wants to test.
>It's so simple: exactly sizeof(void*) .
How do you propose this to be meaningful for pointers to functions?
1. The void* type size is the supremum of all pointer type sizes because it's possible to assign arbitrary pointer type value (including function pointers) to the void* type variable and get back the original value. It's impossible to do if sizeof(void*) < sizeof(wide_pointer_type) for wide_pointer_type (set theory).
Of course, a schizophrenical software architect is capable to invent the C or C++ implementation with unused data fields in all pointers except void* ones. Well, let's remember default argument promotion rules and %p format specification. It's too hard job for lunatic to implement all these features with such exotic pointers...
Make a compromise:
sizeof(pointer_type) <= sizeof(void*)
2. Don't tread on me with member pointers
, otherwise it was an ill-formed question...
3. The only type sizes in C and C++ are introduced via operator sizeof. Strictly speaking any answer without sizeof is incorrect (or the question is ill-formed
)...
Last edited by ArkM; Dec 1st, 2008 at 1:53 pm.