Peter Dimov a écrit :

Loïc Joly wrote:

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Hello everybody,

In boost::shared_ptr, there is a trick to get a type convertible to bool that is not a bool... unspecified_bool_type is a function pointer.

However, with MSVC8.0, and at least when I compile with /clr, I seem to have some problem with it : The null fct ptr seems to be coded 0xffffffff. That is just fine in non /clr compilation, where it gets evaluated as false when converted in boolean. But in /clr mode, it is converted to true.

I can't reproduce this problem with the following code [...]

Ok, I'll try to post a code that reproduces the problem, as soon as I can. It may take a while. Best regards, -- Loïc

Loïc Joly wrote:

Peter Dimov a écrit :

...

...

However, with MSVC8.0, and at least when I compile with /clr, I seem to have some problem with it : The null fct ptr seems to be coded 0xffffffff. That is just fine in non /clr compilation, where it gets evaluated as false when converted in boolean. But in /clr mode, it is converted to true.

I can't reproduce this problem with the following code:

#include <boost/shared_ptr.hpp> #include <iostream>

int main() { boost::shared_ptr<int> px; std::cout << ( px? true: false ) << std::endl; }

compiled as /clr. The compiler does seem to encode a NULL member pointer as -1, but the example prints 0, as it should.

Here is finally some code that reproduces the problem. The compilation options are the default ones when creating a "CLR console application" project:

// TestBoostSharde_ptrAnd.NET.cpp : main project file.

#include "stdafx.h"

#pragma unmanaged #include "boost/shared_ptr.hpp"

class A{}; typedef boost::shared_ptr<A> APtr;

#pragma managed

Thanks very much. You should probably report this managed/unmanaged inconsistency as a bug to Microsoft. In the meantime, can you please add the following: #elif defined( _MANAGED ) static void unspecified_bool( this_type*** ) { } typedef void (*unspecified_bool_type)( this_type*** ); operator unspecified_bool_type() const // never throws { return px == 0? 0: unspecified_bool; } at shared_ptr.hpp:333 and verify if everything works for you. I'll commit it to 1.34 after your confirmation. I wonder whether this new and improved unspecified bool could replace the other variations altogether for 1.35. Member pointers traditionally prove problematic. :-)