Problem adding std::map< int, std::pair< int, const TGeoNode * > > to TTree

[ajfinch]

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ROOT Version:6.20.04
Platform:Centos 7
Compiler:gcc 4.8.5

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When adding a std::map< int, std::pair< int, const TGeoNode * > > as TBranch of a TTree we get the error message:
Warning in <TStreamerInfo::Build>: pair<int,pair<int,const TGeoNode*> >: pair<int,const TGeoNode*> has no streamer or dictionary, data member "second" will not be saved

So presumably I have somehow get a streamer for a TGeoNode included. How do I do that. I tried adding

#pragma link C++ class TGeoNode+;
to the linkdef file but it didn’t help. I also tried

#pragma link C++ class std::pair<int, TGeoNode>+;

but that fails with the message

Warning: Unused class rule: std::pair<int, TGeoNode>

[Wile_E_Coyote]

How about:
#pragma link C++ class std::pair<int, TGeoNode*>+;
or:
#pragma link C++ class std::pair<int, const TGeoNode*>+;

[ajfinch]

Well that was easy! I assumed the pointer version would be implicitly included.
Thanks.

[pcanal]

You will also need:
#pragma link C++ class std::map< int, std::pair< int, const TGeoNode * > >+;
(actually that should be the only you need).

[ajfinch]

Really? The error message went away with Wile_E_Coyote’s suggestion.

[Wile_E_Coyote]

Well, to be on the “safe side”, I would add three lines (even if some are “redundant”):

#pragma link C++ class TGeoNode+;
#pragma link C++ class std::pair<int, const TGeoNode*>+;
#pragma link C++ class std::map<int, std::pair<int, const TGeoNode*> >+;

[ajfinch]

OK, thanks.