RE:[ROOT] ROOT 2.23.12: Accessing functions

From: Masaharu Goto (MXJ02154@nifty.ne.jp)
Date: Tue Apr 04 2000 - 23:50:12 MEST


Hello Matthew,

You need to use 

#pragma link C++ nestedclass;
#pragma link C++ nestedtypedef;

together with what you have tried. There is a historical reason that 
cint does not activated nested classes by default.

Thank you
Masaharu Goto

>
>How do I export a function, which is nested in a namespace, from a
>shared library so that it is available from the CINT interpreter?
>
>Here is a concrete example of the function that I am trying to export
>from a shared library to CINT.  The function, named "cross_section" (see
>below), is nested inside of multiple namespaces.  Here is the contents
>of the header file which declares "cross_section":
>
>  // cross_section.hxx
>  namespace MDL
>  {
>     namespace WAB
>     {
>        double cross_section( double* variables, double* parameters );
>     }
>  }
>
>
>Finally, here is the relevant part of the LinkDef.h file that I am
>trying to use to export "cross_section" from the shared library to the
>CINT interpreter:
>
>
>  // LinkDef.h
>  #pragma link C++ function MDL::WAB::cross_section;
>
>
>This doesn't work, as evidenced by the following error message when I
>try to run rootcint on these two files:
>
>
>  $ rootcint -f cross_sectionDict.cxx -c cross_section.hxx LinkDef.h
>  Note: link requested for unknown function MDL::WAB::cross_section
>FILE:LinkDef.h LINE:21
>
>
>The pragma that I used (above) was the most straightforward method I
>could think of to export the function "cross_section".  Since it didn't
>work, I also tried various combinations of the pragmas documented in the
>CINT Reference Manual (see http://root.cern.ch/root/Cint.phtml?ref and
>search for "#pragma").  In particular, I tried various combinations of
>the following two pragmas that seemed to have something to do with
>namespaces:
>
>
>  #pragma link [C|C++|off] [class|struct|union|enum|namespace] [name];
>  #pragma link [C|C++|off] defined_in [class/struct/namespace name];
>
>
>However, I could find no documentation on how to use these two specific
>pragmas.  Would someone knowledgeable please instruct us in the use of
>these two pragmas?  Would the use of some combination of these two
>pragmas solve my problem with exporting the "cross_section" function
>from a shared library to the CINT interpreter?
>
>I have attached both of the files "cross_section.hxx" and "LinkDef.h" in
>their entirety to this e-mail so that others could try and run the
>command
>
>  $ rootcint -f cross_sectionDict.cxx -c cross_section.hxx LinkDef.h
>
>on them.  Please let us know if you can find the correct combination of
>the CINT pragmas that allow rootcint to run properly on these two files.
>Thank you.
>
>
>--
>Matthew D. Langston
>SLD, Stanford Linear Accelerator Center
>langston@SLAC.Stanford.EDU



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