PMC's and setting flags
Clinton A. Pierce
new P0, .UnManagedStruct
set P0, 512
I get memory allocated for SELF->data just peachy. My question is, I need
to set a flag based on whether the memory management of SELF->data is mine
(because I set it and created my own UnManagedStruct data area) or someone
else's (because ->invoke on an external subroutine gave me a buffer pointer
which was put into an UnManagedStruct).
Where's an appopriate place to put the flag? Can you suggest an example?
Dan Sugalski
>I've got an UnManagedStruct PMC doing some very basic stuff now. If I set it:
>
> new P0, .UnManagedStruct
> set P0, 512
>
>I get memory allocated for SELF->data just peachy. My question is,
>I need to set a flag based on whether the memory management of
>SELF->data is mine (because I set it and created my own
>UnManagedStruct data area) or someone else's (because ->invoke on an
>external subroutine gave me a buffer pointer which was put into an
>UnManagedStruct).
I presume you want the data pointer ignored by the DOD sweep, right?
(Since this is a PMC, the data won't get compacted) That's the
default, unless PObj_is_PMC_ptr_FLAG, PObj_is_buffer_ptr_FLAG, or
PObj_custom_mark_FLAG is set.
--
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
d...@sidhe.org have teddy bears and even
teddy bears get drunk
Clinton A. Pierce
>At 3:46 PM -0400 5/5/03, Clinton A. Pierce wrote:
>>I've got an UnManagedStruct PMC doing some very basic stuff now. If I
>>set it:
>>
>> new P0, .UnManagedStruct
>> set P0, 512
>>
>>I get memory allocated for SELF->data just peachy. My question is, I
>>need to set a flag based on whether the memory management of SELF->data
>>is mine (because I set it and created my own UnManagedStruct data area)
>>or someone else's (because ->invoke on an external subroutine gave me a
>>buffer pointer which was put into an UnManagedStruct).
>
>I presume you want the data pointer ignored by the DOD sweep, right?
>(Since this is a PMC, the data won't get compacted) That's the default,
>unless PObj_is_PMC_ptr_FLAG, PObj_is_buffer_ptr_FLAG, or
>PObj_custom_mark_FLAG is set.
Correct, becuase something external may have a pointer to this memory and I
wouldn't want to trip it up.
I noticed references to user-defined flags in vtables.pod in the "What you
can do and cannot do" section, but I've been unable to find any examples of
this kind of flag. Is this just:
if (SELF->obj->flags & Pobj_private0_FLAG) {
...
}
And using this enum example inside of the class definition makes pmc2c.pl
silently unhappy.
Simon Glover
The flags are defined in pobj.h, along with a bunch of accessor macros
(which use should probably use in preference to fiddling with the flags
directly).
Simon
Dan Sugalski
>At 04:24 PM 5/5/2003 -0400, Dan Sugalski wrote:
>>At 3:46 PM -0400 5/5/03, Clinton A. Pierce wrote:
>>>I've got an UnManagedStruct PMC doing some very basic stuff now.
>>>If I set it:
>>>
>>> new P0, .UnManagedStruct
>>> set P0, 512
>>>
>>>I get memory allocated for SELF->data just peachy. My question
>>>is, I need to set a flag based on whether the memory management of
>>>SELF->data is mine (because I set it and created my own
>>>UnManagedStruct data area) or someone else's (because ->invoke on
>>>an external subroutine gave me a buffer pointer which was put into
>>>an UnManagedStruct).
>>
>>I presume you want the data pointer ignored by the DOD sweep,
>>right? (Since this is a PMC, the data won't get compacted) That's
>>the default, unless PObj_is_PMC_ptr_FLAG, PObj_is_buffer_ptr_FLAG,
>>or PObj_custom_mark_FLAG is set.
>
>Correct, becuase something external may have a pointer to this
>memory and I wouldn't want to trip it up.
Then don't set the flags and you should be OK.
FWIW, I'm halfway (okay, maybe a thirdway) through some basic string
ops--allocating new strings, changing encodings, setting lengths, and
pinning/unpinning their memory.
>I noticed references to user-defined flags in vtables.pod in the
>"What you can do and cannot do" section, but I've been unable to
>find any examples of this kind of flag. Is this just:
>
> if (SELF->obj->flags & Pobj_private0_FLAG) {
> ...
> }
That second -> should be a ., IIRC: SELF->obj.flags. flags is an
element of the obj struct that's in the PMC that SELF points to.