Can I generate a custom compiler error? If so, how? - delphi

Question

Here is what I want to do. I have a project that must be compiled in some version of Delphi or later. I would like to use a conditional compiler directive to test the Delphi version, and then cause a custom compiler error to be generated with a custom message. Being able to generate a custom compiler warning or hint would also be adaquate if an error is not possible.
Sure, I could put some un-compilable giberish in the conditional code segment, and that's fine. But my question is "Can I generate, conditionally, a custom compiler error?"
Thank you Johan and Serg.
Here is the solution, and more details about the issue. I have an application that was originally built in Delphi 2007. It includes Internet Direct components to attach to a Web service. These use SSL. I recently upgraded my SSL libraries to a later version, and these don't play so well with the Delphi 2007 Indy components. I have now added the following compiler directives to ensure that this application will no longer be compiled with Delphi 2007 or earlier:
{$IF CompilerVersion <= 19.0} // Delphi 2007 = 19.0
{$MESSAGE Error 'This project must be compiled in Delphi 2009 or later'}
{$IFEND}

Answer 1

You can use:
{$Message HINT|WARN|ERROR|FATAL 'text string' }
{$MESSAGE 'Boo!'} emits a hint
{$Message Hint 'Feed the cats'} emits a hint
{$messaGe Warn 'Looks like rain.'} emits a warning
{$Message Error 'Not implemented'} emits an error, continues compiling
{$Message Fatal 'Bang. Yer dead.'} emits an error, terminates compiler
See: http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/devcommon/compdirsmessagedirective_xml.html
This works in Delphi 6 and later.

Answer 2

Checking the Delphi version has become easy since CONDITIONALEXPRESSIONS directive was introduced in Delphi 6:
program requires2010;
{$APPTYPE CONSOLE}
{$IFDEF CONDITIONALEXPRESSIONS}
{$IF CompilerVersion >= 21.0} // 21.0 is Delphi 2010
{$DEFINE DELPHI2010}
{$IFEND}
{$ENDIF}
begin
{$IFNDEF DELPHI2010}
{$MESSAGE Fatal 'Wrong Delphi Version'}
{$ENDIF}
Writeln('Continued');
Readln;
end.