Monday November 06, 2006

Upcoming SunStudio Express 3 will include one more c++ language extension. Recently I have implemented explicit template definition aka forward declaration of explicit instantiations. Now this extension is available under -Qoption ccfe -features=gcc command line option.

In the code below compiler will not instantiate (explicitly and implicitly) any members of class S<int>. So it will not waste a time on code generation and optimization. The only source code file should contain explicit template instantiation to successfully link the program.

% cat test.h
template <typename T>
struct S
{
  void foo();
};

template <typename T>
void S<T>::foo()
{
  // a lot of code here
}

extern template struct S<int>;

% cat inst.cc
#include "test.h"

template struct S<int>;

% cat main.cc
#include "test.h"

int main()
{
  S<int> s;
  s.foo();
}

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