Template specialization works with int and fails with double as a class

Question

I hava a following simple template:

template<class T, T N>
bool VerifyGT(T value) {
  return value > N;
}

bool (*test1)(int) = &VerifyGE< int, (int) 0>;  // (1)
bool (*test2)(double) = &VerifyGE< double, (double) 0.0>;  // (2)

When compiling: test1 initialization succeeds, test2 fails with "doesn not match required type". Any ideas?

non-type template parameters have to be intergal types or enumerations. — juanchopanza, Jun 17 '13 at 14:56
Same problem and some discussion http://stackoverflow.com/questions/3800867/templatefloating-point-non-type — Paweł Szczur, Jun 17 '13 at 15:12

score 10 · Accepted Answer · answered Jun 17 '13 at 14:56

10

Non-type template arguments cannot be of floating-point type. Only integral types, enumerations, pointers and references are allowed.

answered Jun 17 '13 at 14:56

Angew is no longer proud of SO

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i hope you don't just copied the answer from juanchopanza's comment :D otherwise i'll take back my +1. – user1810087 Jun 17 '13 at 15:08
@itwasntpete The comment wasn't loaded when I posted the answer. And it doesn't list pointers/refs. – Angew is no longer proud of SO Jun 17 '13 at 15:10

Template specialization works with int and fails with double as a class

1 Answers1