Delphi Basics : $Else command

DelphiBasics

$Else
Compiler Directive

Starts the alternate section of an IfDef or IfNDef

{$IfDef Symbol}
... Code to run when the symbol is defined ...
{$Else}
... Code to run when the symbol is not defined ...
{$EndIf}

Description

The $Else compiler directive starts the alternate section of an IfDef or IfNDef conditional compilation statement.

The code it starts is compiled if the conditional statement returns false.

Related commands

$Define		Defines a compiler directive symbol - as used by IfDef
$EndIf		Terminates conditional code compilation
$IfDef		Executes code if a conditional symbol has been defined
$IfNDef		Executes code if a conditional symbol has not been defined
$IfOpt		Tests for the state of a Compiler directive
$UnDef		Undefines a compiler directive symbol - as used by IfDef

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Example code : Setting up and using a user defined symbol

begin
  // Set our code into dangerous mode
  {$Define DANGERMODE}

  // Are we out of danger?
  {$IfNDef DANGERMODE}
  ShowMessage('We are out danger at present');
  {$Else}
  ShowMessage('We are in danger mode!');
  {$EndIf}

  // Switch off danger mode
  {$UnDef DANGERMODE}
end;

Show full unit code

We are in danger mode!