Re: Rational

[Hans Åberg]

> On 23 May 2018, at 10:39, David Kastrup <address@hidden> wrote:
> 
> Hans Åberg <address@hidden> writes:
> 
>>> On 23 May 2018, at 00:41, David Kastrup <address@hidden> wrote:
>>> 
>>> Hans Åberg <address@hidden> writes:
>>> 
>>>>> On 22 May 2018, at 23:28, David Kastrup <address@hidden> wrote:
>>>>> 
>>>>> Hans Åberg <address@hidden> writes:
>>>>> 
>>>>>>>> I wrote a C++ wrap for that latter, too. As it turns out to be
>>>>>>>> difficult to keep of pointers into the GC heap, I had to use only
>>>>>>>> those that it supplies. Do you do that?
>>>>>>> 
>>>>>>> I don't know what "I had to use only those that it supplies" is supposed
>>>>>>> to mean, so I cannot answer the question.
>>>>>> 
>>>>>> In addition to the collected GC_malloc, there are
>>>>>> GC_malloc_uncollectable and GC_free that correspond to malloc and
>>>>>> free. If one uses the latter pair and have pointers into the GC heap,
>>>>>> they may suddenly disappear, causing strange memory errors.
>>>>> 
>>>>> That's why we don't do that.
>>>>> 
>>>>>> In addition, beware that on some platforms, the GC must be initialized
>>>>>> before the first use (like on MacOS), and if one is using global C++
>>>>>> objects with heap allocations, that must occur before those being
>>>>>> initialized, which is before 'main' starts.
>>>>> 
>>>>> Uhm, you _are_ aware that LilyPond has been used for large scores with
>>>>> Guile data structures for 20+ years?  Don't you think people might have
>>>>> noticed a problem in the mean time?  If you want to contribute useful
>>>>> advice, it might be a good idea to actually look into the LilyPond code
>>>>> base.  The vast majority of LilyPond's memory management in connection
>>>>> with Guile is in lily/include/smobs.hh and lily/include/smobs.tcc .
>>>> 
>>>> So you don't know anything about the Boehm GC?
>>> 
>>> Is there a point to this silliness?
>>> 
>>> <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=19883>
>>> 
>>> Apparently I got to know enough to distill a test case showing that
>>> Guilev2's type system was critically affected by a bug in the Boehm GC's
>>> use of finalizers, leading to workarounds first in the LilyPond code
>>> base and later on in Guile proper.
>> 
>> Relative to that, which seems to be a problem with dead, collected
>> pointers, if one is using what I said above, then the GC keeps those
>> objects pointed at alive.
> 
> How come all of those smart guys knowing better than myself how LilyPond
> works and how garbage collection works and how C++ works can never be
> seen creating a single patch but instead have to rely on telling some
> simpleton like myself how he should be doing things?
> 
> Seriously folks, if you think you are so much more intelligent, get to
> work rather than bother lecturing a moron like myself.

The ultimate in self-assertion is to disagree with those that agree with you.