{{DISPLAYTITLE:OPTION _EXPLICIT}}  
[[OPTION _EXPLICIT]] instructs the compiler to require variable declaration with [[DIM]], [[REDIM]] or an equivalent statement.


{{PageSyntax}}
: [[OPTION _EXPLICIT]]


{{PageDescription}}
* With [[OPTION _EXPLICIT]] you can avoid typos by having QB64 immediately warn in the '''Status area''' of new variables used without previous declaration.
* Enable [[OPTION _EXPLICIT]] temporarily even if a program source file doesn't contain the directive by specifying the '''-e''' switch when compiling via command line (''qb64 -c file.bas -e'').


{{PageErrors}}
* If used, [[OPTION _EXPLICIT]] must be the very first statement in your program. No other statements can precede it (except for comment lines started with an [[Apostrophe|apostrophe]] or [[REM]]).
* Do not use [[OPTION _EXPLICIT]] in [[$INCLUDE]]d modules.


{{PageExamples}}
''Example:'' Avoiding simple typos with [[OPTION _EXPLICIT]] results shown in the QB64 [[IDE]] Status area.
{{CodeStart}}{{Cl|OPTION _EXPLICIT}}

{{Cl|DIM}} myVariable {{Cl|AS}} {{Cl|INTEGER}}

myVariable = 5

{{Cl|PRINT}} myVariabe
{{CodeEnd}}

&lt;center>QB64 IDE Status:&lt;/center>
{{CodeStart}}{{text|██|blue}} '''QB64'''                                                                                _  {{xbox| X }}{{CodeEnd}}
{{TextStart}}  '''File   Edit   View   Search   Run   Options                                           Help''' {{TextEnd}}
{{CodeStart}}┌────────────────────────────────────█{{title|Untitled}}█─────────────────────────────────────────────┐
│OPTION _EXPLICIT                                                                           {{title|↑|black}}
│                                                                                           {{text|█|black}}
│DIM myVariable AS INTEGER                                                                  ▒
│                                                                                           ▒
│myVariable = 5                                                                             ▒
│                                                                                           ▒
│PRINT myVariabe_                                                                           ▒
│                                                                                           ▒
│                                                                                           ▒
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│                                                                                           {{title|↓|black}}
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────────────────────────────────────── Status ──────────────┤{{text|{{Cl|Quick Search Bar|Find[                     }} {{Cl|Quick Search list|↕]}}|aqua}}├─┤
│Variable 'myVariabe' (SINGLE) not defined on line 7                                        │
│                                                                                           {{title|↑|black}}
│                                                                                           ▒
│                                                                                           ▒
│                                                                                           {{title|↓|black}}
{{CodeEnd}}
{{BlueStart}}                                                                                    '''7:17'''{{BlueEnd}}


{{PageSeeAlso}}
* [[DIM]], [[REDIM]]
* [[SHARED]]
* [[STATIC]] 


{{PageNavigation}}
