Correct format for separating declaration and definition of C++ template functions

Question

I'm using this method http://www.parashift.com/c++-faq-lite/separate-template-fn-defn-from-decl.html to separate the definition of a C++ template function from its declaration, to avoid cluttering up my header files with code.

The link uses as an example a function with no arguments or return, but suppose I have a function with an argument. The link would suggest the following arrangement:

// File "f.h" 
template <typename T> void f(T t);

---

// File "f.cpp"
#include "f.h"

template <typename T> void f(T t) {
  // do something
}

template void f<int>(int t);
// other specializations as needed

However it seems the specialization also works if you omit the type in angle brackets, as I suppose the compiler deduces it from the argument type:

template void f(int t);

But I'm wondering, is it valid to do that?

Visual C++ 12 (2013)

Answer 1

Yes, it's valid. [temp.explicit] p3 says:

If the explicit instantiation is for a function or member function, the unqualified- id in the declaration shall be either a template-id or, where all template arguments can be deduced, a template-name or operator-function-id.

Your function has one template parameter and it can be deduced from the function argument, when the function parameter is int the template argument can be deduced as int, so you can (optionally) use the template-name, f, instead of the template-id f<int>.