Correct c++-style cast for fixed size arrays?

Question

I have a small question regarding casts.

Basically, I have the following code :

//Array of ALbyte, size is irrelevant
ALbyte buffer[1000];
//...
alcCaptureSamples(m_audioDevice,(ALCvoid*)buffer, sample);

and based on Scott Meyers Effective C++ advice, I'd like to use a c++-style cast for this.

But I don't really know which one I should pick between reinterpret_cast<ALCvoid*> and static_cast<ALCvoid*>. They say on MSDN that reinterpret_cast is used for converting a pointer to another pointer type.

But in Effective C++, I read

reinterpret_cast is intended for low-level casts that yield implementation-dependent (i.e. unportable) results, e.g., casting a pointer to an int

and that these should be very rare.

Then, which cast should I pick ? I obviously eliminated const_cast and dynamic_cast but can't determine which of the remaining I should use... (and this question didn't really help me as I don't know if the fact that I want to cast a fixed size array into a pointer types from OpenAL impacts or not).

Or should I completely avoid the C++-style cast in this case (but why) ?

Answer 1

In this case you probably don't need to do any casting.

Remember that arrays naturally decays to pointers, and that all pointers can be implicitly casted to void* (which I guess ALCvoid* is).

Answer 2

You should use static_cast whenever possible as it performs compile-time checks: the compiler will not let you cast to an invalid pointer type.

reinterpret_cast cannot perform any compile time checks other than const to non-const. It's rarely used unless programming with older interfaces requiring void*.

Better still though is to design your code so you don't need to do casting: exploting polymorphism can help you avoid them.