Equivalents to MSVC's _countof in other compilers?

Question

Are there any builtin equivalents to _countof provided by other compilers, in particular GCC and Clang? Are there any non-macro forms?

Answer 1

Using C++11, the non-macro form is:

char arrname[5]; size_t count = std::extent< decltype( arrname ) >::value; 

And extent can be found in the type_traits header.

Or if you want it to look a bit nicer, wrap it in this:

template < typename T, size_t N > size_t countof( T ( & arr )[ N ] ) {     return std::extent< T[ N ] >::value; } 

And then it becomes:

char arrname[5]; size_t count = countof( arrname );  char arrtwo[5][6]; size_t count_fst_dim = countof( arrtwo );    // 5 size_t count_snd_dim = countof( arrtwo[0] ); // 6 

Edit: I just noticed the "C" flag rather than "C++". So if you're here for C, please kindly ignore this post. Thanks.

Answer 2

Update: C++ 17 support std::size() (defined in header <iterator>)

You can use boost::size() instead:

#include <boost/range.hpp>  int my_array[10]; boost::size(my_array);