44 #define _MEMORYFWD_H 1 
   46 #pragma GCC system_header 
   50 namespace std _GLIBCXX_VISIBILITY(default)
 
   52 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   67     class allocator<void>;
 
   70   template<
typename, 
typename>
 
   75 _GLIBCXX_END_NAMESPACE_VERSION
 
Declare uses_allocator so it can be specialized in  etc. 
ISO C++ entities toplevel namespace is std.