Use templates for making sure expression is constant

This commit is contained in:
Behdad Esfahbod 2015-10-26 14:05:05 -07:00
parent 5c8174eda3
commit 672ca3b4e6

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@ -240,9 +240,9 @@ static inline unsigned int ARRAY_LENGTH (const Type (&)[n]) { return n; }
#define _ASSERT_STATIC0(_line, _cond) _ASSERT_STATIC1 (_line, (_cond))
#define ASSERT_STATIC(_cond) _ASSERT_STATIC0 (__LINE__, (_cond))
/* Note: C++ allows sizeof() of variable-lengh arrays. So, if _cond is not
* constant, it still compiles (ouch!), but at least we'll get a -Wvla warning. */
#define ASSERT_STATIC_EXPR_ZERO(_cond) (0 * (unsigned int) sizeof (char[(_cond) ? 1 : -1]))
template <unsigned int cond> class hb_assert_constant_t {};
#define ASSERT_STATIC_EXPR_ZERO(_cond) (0 * (unsigned int) sizeof (hb_assert_constant_t<_cond>))
#define _PASTE1(a,b) a##b
#define PASTE(a,b) _PASTE1(a,b)