Using hv_magic() in typemap to create a tied object

rsteinke has asked for the wisdom of the Perl Monks concerning the following question:

I'm trying to provide a tied hash interface to a C object in my XS code. The OUTPUT section of my typemap looks like

T_TIED_HASH

        {
                SV* tie = NEWSV(0, 0);
                HV* hash = newHV();

                /* Get a blessed reference to the pointer, */

                sv_setref_pv(tie, CLASS, (void*)$var);

                /* and tie it to a hash. */

                hv_magic(hash, (GV*)tie, PERL_MAGIC_tied);

                $arg = newRV_noinc((SV*)hash);
        }
[download]

which I was expecting to return a tied HV reference. However, in my test code

my $obj = new TiedXS(1);

ok($obj);
ok(tied $obj);
[download]

the first test succeeds, but the second fails. Ideas?

Ron Steinke rsteinke@w-link.net

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Re: Using hv_magic() in typemap to create a tied object by ysth (Canon) on Aug 04, 2004 at 15:37 UTC
What does `use Devel::Peek; Dump $obj;` [download] show?	[reply] [d/l]
Re^2: Using hv_magic() in typemap to create a tied object by ysth (Canon) on Aug 04, 2004 at 15:47 UTC
Ah, silly me for not seeing it sooner. It's the hash that's tied, not your reference to it. Try tied(%$obj) instead.	[reply]
Devel::Peek object dump result by rsteinke (Scribe) on Aug 04, 2004 at 15:42 UTC
I get RV(0x8199c48) at 0x8163304 REFCNT = 1 FLAGS = (PADBUSY,PADMY,ROK) RV = 0x814cd74 SV = PVHV(0x8167888) at 0x814cd74 REFCNT = 2 FLAGS = (RMG,SHAREKEYS) IV = 0 NV = 0 MAGIC = 0x826f6b0 MG_VIRTUAL = &PL_vtbl_pack MG_TYPE = PERL_MAGIC_tied(P) MG_FLAGS = 0x02 REFCOUNTED MG_OBJ = 0x814cc6c SV = RV(0x8199c34) at 0x814cc6c REFCNT = 2 FLAGS = (ROK) RV = 0x814cd98 SV = PVMG(0x81ae900) at 0x814cd98 REFCNT = 1 FLAGS = (OBJECT,IOK,pIOK) IV = 135647352 NV = 0 PV = 0 STASH = 0x8267a94 "TiedXS" ARRAY = 0x0 KEYS = 0 FILL = 0 MAX = 7 RITER = -1 EITER = 0x0 [download] Ron Steinke rsteinke@w-link.net	[reply] [d/l]
Re: Devel::Peek object dump result by rsteinke (Scribe) on Aug 04, 2004 at 15:51 UTC
Ah, I see now. My mistake. The test should have been `ok(tied %$obj)` [download] I was testing the hash reference for being tied, instead of the actual hash itself. It works now. Thanks! Ron Steinke rsteinke@w-link.net	[reply] [d/l]