A C++ question: when to use "friend class"/"friend template"

[Mojca Miklavec]

Hello,

While this might not be the most appropriate list to ask this type
questions, I hope that there is someone who might be able to help.

When trying to upgrade a port (hugin-app in particular) I had to
modify the following code:

 #ifdef __GNUC__
 friend class Notify::self_type;
 #else
 friend typename Notify::self_type;
 #endif

The Clang compiler (Xcode Xcode 4.6.3 on Lion) failed to work with
"friend class Notify::self_type;". As a temporary patch I removed
#ifdef and made the compiler always end up seeing the code "friend
typename Notify::self_type;", but I believe that this will break the
gcc compilers (I didn't try though because compilation takes forever).

Does anyone know what the proper patch should be?

Thank you,
    Mojca

PS: the latest version of hugin-app claims to work with wxWidgets 2.9
even though it's stated to be experimental. But most problems with
compiling that new version arise from linking to boost.