Re: g++ sometimes doesn't find its standard headers

Re: g++ sometimes doesn't find its standard headers

[Markus Gerwinski]

Andres Chavarria wrote:
> using namespace std;
> vector<int> vec;
> 
> or
> 
> #include <vector>
> std::vector<int> vec;

Well, <vector>, <string> etc. are running fine with that, but my problem was
with <ext/hash_map>. As I meanwhile found out, the hash_map class is not inside
the std namespace, but inside some cryptic namespace "__gnu_cxx". If I use that
one, it works fine, but "__gnu_cxx" doesn't really seem to be a namespace for
public use. ;-)

Does someone know if I really should use this one? Or is there maybe some
#define deep inside gcc3.2 transferring this cryptic namespace into something
else, that's intended for use by the app developer?

Thanks,

  Markus

Re: g++ sometimes doesn't find its standard headers

[LLeweLLyn Reese]

Markus Gerwinski <markus@gerwinski.de> writes:

> Andres Chavarria wrote:
> > using namespace std;
> > vector<int> vec;
> > 
> > or
> > 
> > #include <vector>
> > std::vector<int> vec;
> 
> Well, <vector>, <string> etc. are running fine with that, but my problem was
> with <ext/hash_map>. As I meanwhile found out, the hash_map class is not inside
> the std namespace, but inside some cryptic namespace "__gnu_cxx". If I use that
> one, it works fine, but "__gnu_cxx" doesn't really seem to be a namespace for
> public use. ;-)
> 
> Does someone know if I really should use this one? Or is there maybe some
> #define deep inside gcc3.2 transferring this cryptic namespace into something
> else, that's intended for use by the app developer?

The name __gnu_cxx is intended to inform the app developer (you) that
    a gnu extension is in use. It begins with __ because names
    begining with __ are reserved to the implementation; conforming
    user code can be assumed not to use __gnu_cxx, except to
    deliberate use the extensions. See:

gcc.gnu.org/onlinedocs/libstdc++/libstdc++-html-USERS-3.1/namespace____gnu__cxx.html#_details

The maintainers are aware that the situation is confusing. :-)

Re: g++ sometimes doesn't find its standard headers

[Markus Gerwinski]

LLeweLLyn Reese wrote:
> gcc.gnu.org/onlinedocs/libstdc++/libstdc++-html-USERS-3.1/namespace____gnu__cxx.html#_details

Hmm, this means, identifiers taken from that namespace may as well be internal
implementation details as classes for public use?

Would it run against any current or upcoming convention, if I encapsulated the
namespace with a "#define stdext __gnu_cxx" for my own projects, so I can use a
"stdext::hash_map" class?

> The maintainers are aware that the situation is confusing. :-)

Agreed. &:-)