Example

procedure Foo;
begin
  {$message 'not yet supported'}
end;

From the Free Pascal wiki, page "$message", as it stood on 2023-12-13 after a change by Mathias, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.