Where is the dictionary for basic_string?

ROOT
1

Hi,
If I do the following from the command line:

TClass *c = TClass::GetClass("basic_ostream<char,char_traits<char> >"); c->Property();

I get a reasonable number for the Property. However, if I do the following in a C++ program I’ve built:

[code] int nargs = 2;
char *argv[2];
argv[0] = “t_Template_Class.exe”;
argv[1] = “-b”;
TApplication *app = new TApplication (“t_Template_Class”, &nargs, argv);

TClass *c = TClass::GetClass(“basic_ostream<char,char_traits >”);
cout << "Proprety() = " << c->Property() << endl;[/code]

I get zero for property, but probably more importantly I also get the error message:

Warning in <TClass::TClass>: no dictionary for class basic_ostream<char,char_traits<char> > is available OBJ: TClass basic_ostream<char,char_traits<char> >

I’m guessing I need to do something like gSystem->Load(“blah”) in order to get this to work properly, but I can’t figure out which library I need to fetch. And my usual trick of doing c->GetSharedLibs() returns “” for this class - so I can’t figure it out that way either. Further, making sure the 4 libraries that are loaded when I do gSystem->GetLibraries() (Core, Cint, Mathcore, and Rint) doesn’t make the above error go away.

i’m running ROOT v5.19/4.

Many thanks!

2

Hi Gordon,

that class is known to CINT under its typedef name “ostream”. So TClass::GetClass(“ostream”)->Property() gets you there.

Pretty surprising subject, by the way :slight_smile:

Cheers, Axel.

3

The subject was actally correct – that was the one that I wanted to write about. However, that one I cut/pasted in was a different template I was having similar problems with. Also, I’m on owl shift here at DZERO, so I’m not really thinking straight. :slight_smile:

This is weird – because there are places in the type system where I get back the full template specification. How does root know the two are the same? What trick can I use to figure that out for myself?

And, finally, does your answer explain the behavior I see? Why it works in root but not in my own compiled porgram?

4

Cheers,
Philippe.

5

Hi,

The dictionary for iostream is properly setup by loading (into CINT) the iostream header. Hence in your application use:gROOT->ProcessLine("#include <iostream>");In the ROOT executable this is done by the object of type TRint (which inherits from TApplication).

Cheers,
Philippe.

6

Perfect. Thanks, I’ll try that out.