I'm new to fpc and pascal, i.e. I've never done a project in it, but i've been following the lists for a while and dabbling.

I like using a garbage collector and I know you can replace the memory manager in fpc so i guess it's probably trivial to replace the standard with boehm. Wondered if anyone's done it and how they got on, and if there are issues with the idea.

Thanks

bd

The main issue is that garbage collection is the worst programming idea ever. It lets you get away with bad program design at the cost of slow execution.

Regards,

Adriaan van Os

Adriaan van Os wrote on wo, 18 mrt 2009:

The main issue is that garbage collection is the worst programming idea ever. It lets you get away with bad program design at the cost of slow execution.

Please post remarks like that to the fpc-other list instead. This list is not about advocacy, but about solving (FPC) Pascal programming problems. Using the Boehm garbage collection with FPC is perfectly on topic, flame wars about how good/bad the concept of garbage collection is, is not.

Thanks,

Jonas
FPC mailing lists admin

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I know it has limitations and downsides but I have to respectfully disagree it's the worst programming idea ever. For the stuff I do which is high level applications I don't believe it's going to affect me badly; If i were writing codecs or an operating system then i would find it hard to justify - however, removing a class of errors from my code should speed up my development and be worth it.

bd

In our previous episode, ritchie turner said:

To my best knowledge nobody has experimented with this with FPC. However I can vaguely remember experiments for Delphi (and then I mean native Delphi) have been done.

Since the memory manager concept exists there too (though a bit more gritty and less cleanly abstracted) and the language base principles are the same, I think trying to find that and studying should give you the best start.

If you get a few steps further in that direction, please report back your findings here.

Very many years ago I asked the same question on this mailing list :)

Check it out here:
http://www.hu.freepascal.org/lists/fpc-pascal/2002-November/004229.html

IIRC, it worked on Win32 with boehmgc linked in as a DLL. Don't remember if it was faster than the default memory manager though.

Cheers,
-Krishna

In our previous episode, Krishna said:

I found this:
- http://cc.embarcadero.com/Item/21646

Thanks all, I've got something to go on now.

bd.

It is quite easy to use the boehm gc inside delphi. I did some test a few years ago. Since the fpc memory manager interface is very close to delphi, it should be no problem to port the boehm gc to fpc.

the major disadvantage I see, is, that all the existing code is not gc aware - you loose the benefits of a gc.

cheers,

Adrian.

Thanks all, I've got something to go on now. bd.

bye the way - are you black dog from the haxe list ?

Cheers,

Adrian.

Hi Adrian,

Guilty!

bd.

not able to download. getting timed out.

anyway, I tried compiling the old code and it failed. TMemoryManager seems to have changed a bit. Adjusted the code to match the cmem example given in the manual and I got errors saying that InitThread , DoneThread and RelocateHeap are undefined fields in TMemoryManager. Compiled fine when those three lines were commented out.

It did not crash on Linux! and it seems to collect as well!! (using libgc 6.6 that comes with opensuse 11.1)

Cheers,
--Krishna

oops! posted too early. mseide with boehmgc segfaults at startup (in GC_find_limit) :-(

Cheers,
--Krishna

Hi bd,

than I guess, this is why you look at the boehm gc (that's why I was looking at it). I have put some haxe/neko pascal related code at http://code.google.com/p/pascal4neko/
The code is only tested with delphi, but should work with fpc as well. There is no memory manager for boehm, but some code which shows how to handle the gc for objects and interfaces. If you have any questions, you can contact me directly, because this a bit OT for this list.

Cheers,
Adrian.