title: Equivalents to MSVC's _countof in other compilers?
body: <p>Are there any builtin equivalents to <a href="http://msdn.microsoft.com/en-us/library/ms175773(v=VS.100).aspx" rel="noreferrer"><code>_countof</code></a> provided by other compilers, in particular GCC and Clang? Are there any non-macro forms?</p>