[fpc-devel] PPU version checking

[Tomas Hajny]

On Mon, February 25, 2013 13:42, Sven Barth wrote:
> On 25.02.2013 13:08, John Lee wrote:
>> This is a major pain to quite a few users - I have some units for which
>> source is lost from v2.4. Surely some of the reasons for the changes in
>> ppu version would _not_ cause a problem with later versions if one isn't
>> using this particular feature?
>
> This is the same problem one has with Delphi.
>
>> Maybe someone could generate a (binary?) patch to disable the check (at
>> user's risk)?
>
> If you'd disable the check you would not be able to use e.g. a 2.4 unit
> with 2.6, because the PPU format is different and thus you'd definitely
> (not just perhaps!) get errors when the compiler reads the PPU file.

In other words: _If_ someone is motivated enough for such a task, it would
be possible to create a convertor from one PPU version to another (and I
don't mean a "convertor" only changing the version number but something
that really loads the original format of the particular original version
and stores the data in the new format with new version). I don't think any
of the core developers would be interested in such a task (at least not
just for fun because it would not be much fun most likely), but I don't
want to talk for others.

Moreover, note that in addition to PPU version number you also have
dependencies related changes in RTL and packages. In other words, you
would need to convert the originally used compiled RTL+packages units this
way together with your own (compiled) units in order to be able to use
those units with the new compiler.

Tomas