| Description |
The $IfOpt compiler directive is a meta-directive - it tests for the + or - state of a single character compiler directive.
For example:
{$IfOpt H+}
ShowMessage('Longstrings are set on');
{$EndIf}
It is useful to report on directive settings at the start of a program, when testing.
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| Notes |
$IfOpt can be used multiple times in your code.
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| Related commands |
| $Define |
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Defines a compiler directive symbol - as used by IfDef |
| $Else |
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Starts the alternate section of an IfDef or IfNDef |
| $EndIf |
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Terminates conditional code compilation |
| $IfDef |
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Executes code if a conditional symbol has been defined |
| $IfNDef |
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Executes code if a conditional symbol has not been defined |
| $UnDef |
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Undefines a compiler directive symbol - as used by IfDef |
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| Example code : Show various default directive settings |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
begin
// Show the default settings of various compiler directives
{$IfOpt A+}
ShowMessage('Align is On');
{$Else}
ShowMessage('Align is Off');
{$EndIf}
{$IfOpt B+}
ShowMessage('BoolEval is On');
{$Else}
ShowMessage('BoolEval is Off');
{$EndIf}
{$IfOpt H+}
ShowMessage('LongStrings is On');
{$Else}
ShowMessage('LongStrings is Off');
{$EndIf}
end;
end.
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| Hide full unit code |
Align is Off
BoolEval is Off
LongStrings is On
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