[Boost-users] Why does gcc require explicit template arguments with my boost::bind

Subject: [Boost-users] Why does gcc require explicit template arguments with my boost::bind
From: Chris Stankevitz (chrisstankevitz_at_[hidden])
Date: 2012-12-06 00:34:06

Hello,

Below I implement a function "Chain" that takes two functions and
executes them both.

The first approach succeeds: direct function call.

The second approach succeeds: call via bind with explicit template arguments

The third and fourth approaches fail: call via bind without explicit
template arguments (with/without boost::protect)

Question: Why do I have to use explicit template arguments when using
bind with Chain?

Thank you,

Chris

===

#include <boost/bind.hpp>
#include <boost/function.hpp>

template <typename TAFunc1, typename TAFunc2>
void Chain(const TAFunc1& Func1, TAFunc2& Func2)
{
   Func1();
   Func2();
}

void f()
{
}

void foo()
{
  boost::function<void()> x = boost::bind(f);

  boost::function<void()> y = boost::bind(f);

  Chain(x, y);

  boost::bind(Chain<boost::function<void()>, boost::function<void()> >, x, y)();

  boost::bind(Chain, x, y)();

  boost::bind(Chain, boost::protect(x), boost::protect(y))();
}