Peter Dimov wrote:

Markus Schöpflin wrote:

...

Hello,

as part of its interface intrusive_ptr requires the user to supply two functions:

void intrusive_ptr_add_ref(T * p); void intrusive_ptr_release(T * p);

These are called from within the implementation of the intrusive_ptr class. When compiling intrusive_ptr_test, cxx complains that intrusive_ptr uses undeclared functions, because the test includes the header file for intrusive_ptr before declaring those two functions.

Are you sure that the compiler is correct? A dependent unqualified call is resolved at instantiation time.

Hmm, have a look at this: ---%<--- template <class T> struct foo { void bar() { foobar(); } }; void foobar() {} void argl() { foo<int> f; f.bar(); } --->%--- Comeau Online has this to say: ---%<--- "ComeauTest.c", line 2: error: identifier "foobar" is undefined void bar() { foobar(); } ^ 1 error detected in the compilation of "ComeauTest.c". --->%--- What do you think? Markus

Peter Dimov wrote:

Markus Schöpflin wrote:

...

Hmm, have a look at this:

---%<--- template <class T> struct foo { void bar() { foobar(); } };

This call to foobar is not dependent on T. Try

template <class T> struct foo { void bar( T * p ) { foobar( p ); } };

OK, what about this: ---%<--- template <class T> struct foo { T *p; void bar() { foobar(p); } }; void foobar(int *p) {} void argl() { foo<int> f; f.bar(); } --->%--- I think this resembles the situation at hand now. I still get: ---%<--- "ComeauTest.c", line 3: error: identifier "foobar" is undefined void bar() { foobar(p); } ^ detected during instantiation of "void foo<T>::bar() [with T=int]" at line 10 --->%--- And it works if you insert 'void foobar(int *p);' before struct foo. Markus

Johan Nilsson wrote:

Markus Schöpflin wrote:

[...]

...

---%<--- template <class T> struct foo { T *p; void bar() { foobar(p); } };

void foobar(int *p) {}

void argl() { foo<int> f; f.bar(); } --->%---

I don't think lookup works with built-in types. Try the above with e.g. "struct bar{};" instead of "int".

You are right. Sigh, obviously I don't manage to create a small reproducer for the error seen at http://preview.tinyurl.com/23towf. (Scroll down to the last five errors, ignore the rest, this has been fixed by now.) But yet I have learned by now that usually this compiler knows the standard better than me. Could anyone confirm or deny that this is indeed an error? TIA, Markus

Peter Dimov wrote:

Markus Schöpflin wrote:

...

Sigh, obviously I don't manage to create a small reproducer for the error seen at http://preview.tinyurl.com/23towf. (Scroll down to the last five errors, ignore the rest, this has been fixed by now.)

Can you please try changing

intrusive_ptr_add_ref( detail::get_pointer( m_ptr ) );

to

T * p = detail::get_pointer( m_ptr ); intrusive_ptr_add_ref( p );

?

It could be the intermediate get_pointer call that is tricking the compiler into thinking that the call is not dependent.

I modified the constructor into: intrusive_ptr(const pointer &p, bool add_ref = true): m_ptr(p) { if(m_ptr != 0 && add_ref) { T* p = detail::get_pointer(m_ptr); intrusive_ptr_add_ref(p); } } But I still get: cxx: Error: ../../../boost/interprocess/smart_ptr/intrusive_ptr.hpp, line 77: identifier "intrusive_ptr_add_ref" is undefined (undeclared) detected during instantiation of "boost::interprocess::intrusive_ptr<T, VoidPointer>::intrusive_ptr(const boost::interprocess::intrusive_ptr<T, VoidPointer>::pointer &, bool) [with T=n_transitive::X, VoidPointer=VP]" at line 468 of "intrusive_ptr_test.cpp" intrusive_ptr_add_ref(p); --------^ Markus

Peter Dimov schrieb:

Markus Schöpflin wrote:

...

But I still get:

cxx: Error: ../../../boost/interprocess/smart_ptr/intrusive_ptr.hpp, line 77: identifier "intrusive_ptr_add_ref" is undefined (undeclared) detected during instantiation of "boost::interprocess::intrusive_ptr<T, VoidPointer>::intrusive_ptr(const boost::interprocess::intrusive_ptr<T, VoidPointer>::pointer &, bool) [with T=n_transitive::X, VoidPointer=VP]" at line 468 of "intrusive_ptr_test.cpp" intrusive_ptr_add_ref(p); --------^

This is a point of instantiation error. It's caused by intrusive_ptr_add_ref not being defined in one of the associated namespaces of n_transitive::X. Looking at the test, it looks like namespace N, the home of N::base, is the appropriate place for standard-conforming compilers.

In

http://svn.boost.org/trac/boost/browser/trunk/libs/smart_ptr/test/intrusive_...

I've defined intrusive_ptr_* as inline friends of base, but an out of class definition in N will also work.

Thank you very much for your help, tomorrow I'll try to move those two functions to N to see if it works then. But I still think that this kind of implicit interfacing with client code should be avoided. Or is this considered OK by others? Markus

Peter Dimov schrieb: [...]

Thanks Peter for your explanations.

...

Markus Schöpflin wrote:

Thank you very much for your help, tomorrow I'll try to move those two functions to N to see if it works then.

But I still think that this kind of implicit interfacing with client code should be avoided. Or is this considered OK by others?

I just followed boost::intrusive_ptr path, but I admit that I really don't understand unqualified calls and ADL. I will move those functions and check several platforms to see if everything is OK.

Markus

Ion