Torsten Foertsch wrote: > Hi, > > the a pointer to current interpreter is somehow written to the Perl > interpreter itself by this macro: > > #ifndef HvPMROOT > # if MP_PERL_VERSION_AT_LEAST(5, 9, 5) > #define MP_THX_INTERP_SET(thx, interp) \ > ((XPVMG*)SvANY(*Perl_Imodglobal_ptr(thx)))->xmg_u.xmg_magic = > (MAGIC*)interp > # else > #define MP_THX_INTERP_SET(thx, interp) \ > ((XPVMG*)SvANY(*Perl_Imodglobal_ptr(thx)))->xmg_magic = (MAGIC*)interp > # endif > #else > #define MP_THX_INTERP_SET(thx, interp) \ > HvPMROOT(*Perl_Imodglobal_ptr(thx)) = (PMOP*)interp > #endif
That's right, its so we can get to the modperl_interp_t from a good perl THX. It's seriously a hack, but it does the job quite nicely, and there doesn't seem to be a much better way to do it. It just uses an unused magic field to stash that pointer. > What is HvPMROOT and what is Perl_Imodglobal_ptr? Not even sure what HvPMROOT was, but it was just a semi-arbitrairly chosen field of the modglobal HV that wasn't likely to be used, ever. > Are these normal Perl > variables that can also be accessed from Perl level? Nope, they are deep inside the guts of Perl. modglobal is documented somewhere in perlguts, and it's just a general purpose HV* in the interp structure for this kind of magic. > If not why are here > special variables used? Basic idea if I remember correctly was to be able to get back to the modperl_interp_t from a Perl interp. To make matters trickier, you need to be able to retrieve it out of there without actually entering Perl-land. That's why instead of sticking it in the modglobal hash, it's hagning off one of it's unused struct member. > Can that not be something like > $Modperl::CurrentInterpreter or so? Seems the original idea was to avoid going thru the perl runtime to figure it out. Hope this helps a little. ------------------------------------------------------------------------ Philippe M. Chiasson GPG: F9BFE0C2480E7680 1AE53631CB32A107 88C3A5A5 http://gozer.ectoplasm.org/ m/gozer\@(apache|cpan|ectoplasm)\.org/
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