Il 26/12/2017 18:43, Karoly Balogh (Charlie/SGR) ha scritto:
HI,
On Tue, 26 Dec 2017, Thorsten Engler wrote:
Item: BYTE BASED ItemPtr;
Ignoring any other considerations for now, I would have at least used a
logical extension derived from already supported syntax:
Item: Byte absolute ItemPtr^;
As far as I understand (I did not try) this was once supported, but
explicitly removed by FPC 2.4.0 from Absolute keyword dereferencing is no
longer allowed:
http://wiki.freepascal.org/User_Changes_2.4.0#Absolute_variable_declarations
As the reasoning there shows, it's a very slippery slope this, which could
open a can of worms, so careful people. :)
I'd not be in favour of using the same syntax for two quite different
beasts.
Although the practice implementation is similar, the semantics is
completely different:
ABSOLUTE declares a variable whose storage is known and assigned at
compile time.
BASED declares a variable whose storage is unknown, and will only be
instantiated at run time.
Mixing the two things may cause a lot of troubles, and most likely
that's the reason why it was removed from fpc 2.4.0.
Giuliano
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