[Log4cpp-devel] getAllAppenders fail on Win32 with log4cpp as DLL

[Dirk L. <di...@no...>]

Hi,

today I had a strange problem with the Categroy::getAllAppenders () 
function. I'm writing a small gui dialog to customize the logging during 
the execution of the program. Right now I can edit the categories with 
the vector returned from getCurrentCategories (). I wanted to display 
also the list of attached appenders so I asked for the AppenderSet via 
the function getAllAppenders (). But the returned set is not valid, 
since the implementation of the _Tree used in the std::set contains a 
static _Nil node, which is not the same in the process and in the DLL.
As a result when I try to iterate the returned set I get an invalid 
AppenderSet::end () iterator and the iteration continues until the 
software crashes.

Perhaps as little longer description: the STL implementation of the 
std::set in Microsoft uses a std::_Tree. The std::_Tree maintains one 
static _Nil and one static _Nilrefs member, that is used to mark the 
ends in the trees. This _Nil is used in within all _Trees with the same 
template arguments. Compiling log4cpp as a DLL will result in having one 
static instance of these to members within the DLL, that are not the 
same static instances of theses members in the Application. So copying 
the AppenderSet within the context of the DLL will use the DLLs instance 
of the _Nil pointer to mark the ends in the _Tree. But iterating through 
the std::set within the application context will result in the usage of 
a different _Nil element. So the iteration through the _Tree will never 
end, since the end of the _Tree will never match the _Nil element.


Any ideas how to circumvent the problem?

Thanks
Dirk