Re: context pointer always NULL for "c-tor" when created w/ Reflex::ClassBuilder::AddFunctionMember ?

From: Sebastien Binet <binet_at_cern.ch>
Date: Tue, 17 May 2011 12:22:16 +0200

On Tue, 17 May 2011 11:04:10 +0200, Axel Naumann <Axel.Naumann_at_cern.ch> wrote:
> Hi Sebastien,
>
> I don't know how you bind it to Go. How does the constructor get
> invoked?

that's probably done by TTree/TBranch... I am not calling it directly.

> I.e. is Reflex::FunctionMember::Invoke() really called? Can you
> send the backtrace?

ah! got it.
it is probably b/c of:

http://root.cern.ch/lxr/source/cint/reflex/src/Object.cxx#89
 80 //-------------------------------------------------------------------------------
 81 // Invoke a data member of this object. Sign can be used for finding overloaded funs.
 82 // Put return value(if not void) into ret.

 83 Member m = TypeOf().FunctionMemberByName(fm, sign);  84
 85 if (!m) {
 86 throw RuntimeError("No such MemberAt " + fm);  87 }
 88
 89 m.Invoke(*this, ret, args);
 90 }

Object::Invoke not passing m.Stubcontext() to m.Invoke...

-s

>
> Cheers, Axel.
>
>
> Sebastien Binet wrote on 05/17/2011 10:46 AM:
> >
> > hi there,
> >
> > (still playing with Go)
> > I am seeing something rather strange:
> >
> > say I have these structs:
> >
> > /** edm **/
> > typedef struct {
> > double E;
> > double T;
> > } Det;
> >
> > typedef struct {
> > Det A;
> > Det B;
> > } Event;
> >
> > size_t g_sz_det = sizeof(Det);
> > size_t g_sz_evt = sizeof(Event);
> >
> >
> > and the corresponding c-tor stub functions:
> > /* stub functions for Event */
> > void ctor_Event(void *retaddr, void *mem, void* args, void* ctx)
> > {
> > fprintf(stderr, "::ctor-fct[Event] [%p] [%p] [%p] [%p]\n", retaddr, mem, args, ctx);
> > void* dummy = 0;
> > if (retaddr) *(void**)retaddr = (Event*)realloc(mem, sizeof(Event));
> > else dummy = (Event*)realloc(mem, sizeof(Event));
> > if (dummy) {}
> > }
> >
> > /* etc... */
> >
> > the ctor_Event stub function is attached to the Event Reflex::Type like
> > so:
> > Reflex::ClassBuilder cb = ...;
> > Reflex::Type ty_ctor = Reflex::FunctionTypeBuilder(ty_void);
> > void *ctx = &g_sz_evt;
> > cb.AddFunctionMember(ty_ctor, "Event", &ctor_Event, ctx, NULL,
> > Reflex::PUBLIC|Reflex::CONSTRUCTOR);
> >
> >
> > so far so good, and when iterating over the function members of the
> > "Event" type I do see:
> > :: Evt-size: 32 32
> > :: Evt-mbrs: 2
> > :: Evt-type: 117
> > :: Evt-name: Event
> > :: Evt-id: 0x11c28d0
> > :: Evt-fct-mbrs: 3
> > :: fct-mbr[0][Event] - ctx [0x6033b8] stub-fct[0x401960]
> > :: fct-mbr[1][IsA] - ctx [0x11c3910] stub-fct[0x7f9892ed2290]
> > :: fct-mbr[2][ShowMembers] - ctx [0x11c3910] stub-fct[0x7f9892ed1d00]
> >
> > ie: the correct address for both the context pointer and the stub
> > function (calling resp. Member::Stubcontext() and Member::Stubfunction())
> >
> > but when the ctor_Event function is invoked:
> > ::ctor-fct[Event] [(nil)] [0x13b3500] [0x11c85d0] [(nil)]
> >
> > the ctx pointer is always NULL, eventhough FunctionMember::Invoke does
> > pass the fStubCtx to fStubFP:
> >
> > // parameters need more checking FIXME
> > fStubFP(retaddr, mem, paramList, fStubCtx);
> >
> >
> > (I'd like to use that context pointer to pass a few extra informations
> > needed for the proper initialization of the Go runtime when
> > instantiating the struct instance...)
> >
> > am I doing something wrong ?
> >
> > -s
> >

-- 
#########################################
# Dr. Sebastien Binet
# Laboratoire de l'Accelerateur Lineaire
# Universite Paris-Sud XI
# Batiment 200
# 91898 Orsay
#########################################






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Received on Tue May 17 2011 - 12:22:21 CEST