On Sun, 20 Nov 2022, 19:45 Tan, Qiye via Libstdc++, <libstdc++@gcc.gnu.org>
wrote:

> Hi all,
>
> I'm new in C++ who have an interest in the implementation of C++ STL.
> Recently, I tried to implement my own vector template. However, when I
> implemented my own iterator, I found that I had no idea how to
> detect whether it is dereferencable. Therefore, I began to explore the
> libstdc++, but I found that for some member functions, I can only find the
> declaration but no definition. For example, the 'bool
> __gnu_debug::_Safe_iterator_base::_M_singular(  ) const', 'void
> __gnu_debug::_Safe_iterator_base::_M_detach(  )', etc. They are declared in
> 'libstdc++-v3/include/debug/safe_base.h'. I can guess that '_M_singular'
> may just check if '_M_sequence' is NULL, but I still want to find their
> definition. Can someone help me? Thank you so much.
>

François and Arsen gave the answer already, but for future reference you
could clone the git repository and use 'git grep _M_singular' to find that.



> Best,
> Qiye Tan
>