c++ - Can I use decltype (or something similar) for explicit template instantiation without signature duplication?

Question

I want to instantiate

template<typename T> void foo(
    T& t,
    SomeType some_parameter,
    AnotherType another_parameter,
    EtcType yet_another_parameter,
    AsYouCanTell this_is_a_very_long_signature);

that is, a function with a long signature. Now, I know how to do this:

template void foo<int>(
    int& t,
    SomeType some_parameter,
    AnotherType another_parameter,
    EtcType yet_another_parameter,
    AsYouCanTell this_is_a_very_long_signature);

But I have to duplicate the signature. Also, what if want specific instantiation for 5 different types - do I copy it 5 times? Doesn't make sense...

I was thinking maybe I could write

template decltype(foo<int>);

but for some reason this doesn't work. Why?

Answer 1

It actually works but the syntax is different:

template
decltype(foo<int>) foo<int>;

decltype gives you a type but the explicit instantiation requires a declaration which is a type followed by a name.

Tried with GCC 4.9.1; it works as expected and compiles without any warnings even with the -pedantic flag.