1 #ifndef BENCHMARK_ARRAYSIZE_H_
2 #define BENCHMARK_ARRAYSIZE_H_
3 
4 #include "internal_macros.h"
5 
6 namespace benchmark {
7 namespace internal {
8 // The arraysize(arr) macro returns the # of elements in an array arr.
9 // The expression is a compile-time constant, and therefore can be
10 // used in defining new arrays, for example.  If you use arraysize on
11 // a pointer by mistake, you will get a compile-time error.
12 //
13 
14 // This template function declaration is used in defining arraysize.
15 // Note that the function doesn't need an implementation, as we only
16 // use its type.
17 template <typename T, size_t N>
18 char (&ArraySizeHelper(T (&array)[N]))[N];
19 
20 // That gcc wants both of these prototypes seems mysterious. VC, for
21 // its part, can't decide which to use (another mystery). Matching of
22 // template overloads: the final frontier.
23 #ifndef COMPILER_MSVC
24 template <typename T, size_t N>
25 char (&ArraySizeHelper(const T (&array)[N]))[N];
26 #endif
27 
28 #define arraysize(array) (sizeof(::benchmark::internal::ArraySizeHelper(array)))
29 
30 }  // end namespace internal
31 }  // end namespace benchmark
32 
33 #endif  // BENCHMARK_ARRAYSIZE_H_
34