procedure Assert (Condition: Boolean);
procedure Assert (Condition: Boolean; const Message: String);
Assert checks the given Condition at run-time. If it is true, it does nothing. If it is false, it raises a runtime error, using the second argument for the message if given.
However, if the switch --no-assertions is given (see GPC Command Line Options), Assert is deactivated. It still evaluates the condition if it has side effects, but never raises a runtime error.
Assert is a Borland Delphi extension.