Hi Jonas,
This functionality works in all versions of Delphi 5-2007. We support them
all, and we have done so for years. We have no problems to compile with such
optimizations turned off. We need proper reference counting. We have over
300 Delphi components in 5 released and 3 libraries under current
development, spreading over 4 million lines of code. We are looking to port
it to Linux, and other platforms. The Lazarus looks like the natural
solution. We have no problems creating a clone of it, or developing
alternative compiler from scratch. We plan to allow C++ users to also use
the library, as we provide C++/MFC and .NET component wrappers to our
customers. If we need to we can simply fix the compiler for our needs and
sell only compiled C++ supporting versions, or if you agree to allow some
override to the behavior we can support the Lazarus and free Pascal too. We
believe that as one of the biggest component vendors in the world, our
support for Lazarus will help the project a lot. However for that we
crucially need this problem fixed. CodeGear has done fixes for us in the
past, in order to help us continue to support the platform, as they have
done for other vendors, and we are very, very grateful for that, and have
help them (convert) many of our .NET customers. We will be equally grateful
for any help you can offer in our attempts to support Lazarus. We believe
this will only help the community, and the popularity of the product.
I have downloaded the source, and I will see if we can tweak it and add some
compiler option to support this somehow.
You can take a look at our currently available products here : www.mitov.com
, and yes, we are working to make all this available in Lazarus ;-) .
With best regards,
Boian Mitov
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Mitov Software
http://www.mitov.com
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----- Original Message -----
From: "Jonas Maebe" <[EMAIL PROTECTED]>
To: "FPC developers' list" <fpc-devel@lists.freepascal.org>
Sent: Thursday, June 19, 2008 4:39 AM
Subject: Re: [fpc-devel] Need patch for bugs : 0011503 / 0009472
On 19 Jun 2008, at 13:21, Boian Mitov wrote:
Thank you!
I don't understand. 0011503 is a major failure. Is it in the compiler or
in some library?
Please read the comments to http://bugs.freepascal.org/view.php? id=9472.
The whole issue is discussed there in great detail.
This is a huge problem. This code must work the same way in both cases
but it does not. We are porting a huge library of over 4 million lines
of code from Delphi. This is a major show stopper. I can probably take a
look in the compiler as it will be much easier and faster for us to fix
the compiler to be Delphi compatible rather than rewriting the
libraries. They rely heavily on interfaces and the correct reference
counting. Rewriting this even if desirable will delay the project with
at least a year at best. By definition when there are no active
references to an interface it must be released. This is a total failure
of the functionality.
There are active references, namely in an invisible temp. When this
invisible temp is destroyed (at the function exit), the interface is
freed.
It is wrong to assume that implicit temps which still contain references
to interfaces (or ansistrings, or any other reference counted type) can
never exist, because this is an implementation detail over which the
compiler has full control. This can also happen in Delphi under certain
circumstances by the way (namely if it cannot guarantee that optimising
the interface assignment is safe without using a temp).
The purpose of automatic reference counting is simply that memory
management is automated. It is not to guarantee the same semantics as
what you would get in a manual reference counting scheme where you are in
full control of when and where reference counts are increased and
decreased. In principle, a periodic mark and sweep would also still be
correct behaviour.
Newer versions of FPC optimise assignments of function results more
aggressively so you will more often get reference counting behaviour like
in Delphi, but we do not guarantee in any way that it will be 100%
identical. We only emulate the Delphi language, not the implementation
details of the Delphi compiler or code generator.
Jonas
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