Hello,

I have a TPersistent decendant class that causes the following compiling error:

"Only class which are compiled in $M+ mode can be published"

This is the inheritance:

TPersistent (Classes unit)
+-TPressStreamable (PressClasses unit)
+-TPressSubject (PressSubject unit)
+-TPressObject (PressSubject unit)

Am I missing something?

WinXP and the just released Lazarus 0.9.20 (with FPC 2.0.4)

Thanks,

Probably you have a published member in your class which is not a descendent of TPersistent. Only TPersistent descendents can be published members of a class (which in itself must be a TPersistent descendent).

So, if TPressObject has a published property
  Property MyProp : TMyPropClass Read...

then TMyPropClass must also descend from TPersistent.

Michael.

This is the code:

   TPressObject = class(TPressSubject)
     _Id: TPressString;
   private  // <- compiler stops here
     ...

and this is the inheritance:

TPersistent (Classes unit)
+-TPressStreamable (PressClasses unit)
+-TPressSubject (PressSubject unit)
+-TPressObject (PressSubject unit)
+-TPressAttribute (PressSubject unit)
+-TPressString (PressSubject unit)

I also tried to move the member to the published area; declared the class under the $M+ directive; but no success. Moving the _Id member to the private area solves the compilation problem.

Hints? Anyway I'll perform some tests under Linux in a couple of hours.

Thank you,

The problem is - TPressString is a forward declaration and the compiler doesn't know that it inherits from TPersistent. Is this the expected behavior?

Thanks,

Yes.
The compiler has no idea that _Id is publishable, and therefor rejects it.

Michael.

Thanks Michael.

But is this the correct behavior, a non implemented feature or a bug? (note - Delphi doesn't raise this error)

As far as I'm concerned it's correct behaviour, but you'll have to ask the compiler gurus for confirmation :-)

Michael.