How to implement reflection in C++

[Siegfried]

Java, C# and other languages allow one to enumerate all the data
members of a class or struct thru their respective reflection APIs.

Varios Microsoft specific extensions to their C++ compiler allows one
to do the same (I'm thinking of both the COM extentions as wells as the
managed extensions).

I don't believe g++ supports either of these. Does anyone have some
sample code that will read a g++ .o file (that was compiled with the
debug option turned on), or a g++ executable image and extract the meta
data about a type so I can enumerate the datamembers?

Thanks,
Siegfried

 

[roberts.noah]

Java, C# and other languages allow one to enumerate all the data
members of a class or struct thru their respective reflection APIs.

Varios Microsoft specific extensions to their C++ compiler allows one
to do the same (I'm thinking of both the COM extentions as wells as the
managed extensions).

I don't believe g++ supports either of these. Does anyone have some
sample code that will read a g++ .o file (that was compiled with the
debug option turned on), or a g++ executable image and extract the meta
data about a type so I can enumerate the datamembers?

I'm gonna bet that such a thing isn't available. Maybe if you explain
why you need it, or think you need it, someone could help you find a
more available solution.

 

[peter steiner]

Java, C# and other languages allow one to enumerate all the data
members of a class or struct thru their respective reflection APIs.

Varios Microsoft specific extensions to their C++ compiler allows one
to do the same (I'm thinking of both the COM extentions as wells as the
managed extensions).

I don't believe g++ supports either of these. Does anyone have some
sample code that will read a g++ .o file (that was compiled with the
debug option turned on), or a g++ executable image and extract the meta
data about a type so I can enumerate the datamembers?

have a look at the objdump(1) sources which reads symbols from gcc
generated object files.

but i don't think you will be able to get the information that you need
from the object files, as these linker input files do not necessarily
contain the original C++ object layout in processable form.

you will need C++ parser output to get full identifier information for
C++ source files.

if you don't want to use a full-blown C++ parser implementation, for
example the wrapper/interface generator tool swig has a mode to output
a XML or lisp s-expression formatted abstract syntax tree for given
source files. this gives you parseable data to further work with.

see http://www.swig.org

-- peter

 

[Roland Pibinger]

have a look at the objdump(1) sources which reads symbols from gcc
generated object files.

or nm
(http://www.gnu.org/software/binutils/manual/html_chapter/binutils_2.html)
on Unix or dumpbin for VC++.

Best wishes,
Roland Pibinger

 

[=?ISO-8859-15?Q?Juli=E1n?= Albo]

I don't believe g++ supports either of these. Does anyone have some
sample code that will read a g++ .o file (that was compiled with the
debug option turned on), or a g++ executable image and extract the meta
data about a type so I can enumerate the datamembers?

Supposing that you find or write such a tool, you must consider that the
member functions of a class can be spawned over several .o files.

 

[Gianni Mariani]

Java, C# and other languages allow one to enumerate all the data
members of a class or struct thru their respective reflection APIs.

Varios Microsoft specific extensions to their C++ compiler allows one
to do the same (I'm thinking of both the COM extentions as wells as the
managed extensions).

I don't believe g++ supports either of these. Does anyone have some
sample code that will read a g++ .o file (that was compiled with the
debug option turned on), or a g++ executable image and extract the meta
data about a type so I can enumerate the datamembers?

Go ask the gcc people. It's not standard C++ (I wish it was too) so
it's off topic here.

 

[WaRCHieFX]

Take a look at the RTTI chapter in Thinking in C++
(www.bruceeckel.com), i don't remember which volume.

 

[Ira Baxter]

you will need C++ parser output to get full identifier information for
C++ source files.

A front end C++ parser that can be straightforwardly configure to do this
can be seen at
www.semanticdesigns.com/Products/FrontEnds/CppFrontEnd
It handles full GCC.