Re: template friends, specialization usage change with gcc 4.0.1

Valentin Samko <>
4 Jun 2006 09:17:45 -0400
Tom Mander wrote:

template <class K, class V>
class Hash
    enum { DEFAULT_SIZE = 64 };
    typedef unsigned int (*HashFunc)(const K&);
    Hash(int size = DEFAULT_SIZE, HashFunc = hashFunc);

class A {
    friend unsigned int hashFunction(const A&); //used by Hash::Hash in
    friend unsigned int hashFunc<A>(const A&); //used by Hash::Hash in

You are missing some code here. Where is the hashFunc template function declared? The same
for the non template hashFunc function. It is very hard to tell the problem without seeing
the code that you are trying to compile. Most likely the difference in behaviour is due to
the two phase template instantiation done by gcc4, where it "parses" templates in two
phases, and not only when they are instantiated (like gcc3).


Valentin Samko -

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