[Boost-users] [Function][Bind] Strange problem with g++ 4.5

Subject: [Boost-users] [Function][Bind] Strange problem with g++ 4.5
From: Maxime van Noppen (maxime_at_[hidden])
Date: 2010-05-15 14:19:39

Hi,

I've got a very strange problem with Boost.Function used in conjunction
with Boost.Bind with g++ 4.5.0.

Here is the minimal test case:

----------------gtest.cc---------------------------------
#include <boost/bind.hpp>
#include <boost/function.hpp>

#include <iostream>

int fun(const int* id)
{
  std::cout << "id: " << id << std::endl;
  std::cout << *id << std::endl;

  return 0;
}

int main()
{
  typedef boost::function<int ()> func_t;

  int id = 42;

  std::cout << "id: " << &id << std::endl;
  func_t f = boost::bind(&fun, &id);
  //std::cout << f << std::endl;
  func_t g = f;
  g();

  return 0;
}
-------------------------------------------------

When compiled with -O2 the program crashes:

-------------------------------------------------
$ g++ -O2 gtest.cc && ./a.out
id: 0x7fff3f7f85ec
id: 0
Segmentation fault
-------------------------------------------------

The problem seems to be inlining, when compiled with -O0 or -O2
-fno-inline everything works fine:

-------------------------------------------------
$ g++ -O2 -fno-inline gtest.cc && ./a.out
id: 0x7fff32b81a9c
id: 0x7fff32b81a9c
42
$ g++ -O0 gtest.cc && ./a.out
id: 0x7fff960b270c
id: 0x7fff960b270c
42
-------------------------------------------------

What is very strange is that if I uncomment the std::cout of f
everything works fine:

-------------------------------------------------
$ g++ -O2 gtest.cc && ./a.out
id: 0x7fff738619ac
1
id: 0x7fff738619ac
42
-------------------------------------------------

If the Boost.Function is not copied to g (ie, use f) everything works.

Everything works fine with g++ (GCC) 4.4.3 20100316 (prerelease). I'm
using Linux x86_64 with boost 1.42 and 1.43.

Any idea of what may be going wrong here?

-- 
Maxime