Difference between revisions of "Metacommand"

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* '''Qbasic''' Metacommands are normally used at the program start and are in effect throughout the program.
 
* '''Qbasic''' Metacommands are normally used at the program start and are in effect throughout the program.
* [[$CHECKING]]: OFF''' should only be used with '''errorless''' code where every CPU cycle counts! Use '''ON''' to re-enable event checking.
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* [[$CHECKING]]: OFF should only be used with '''errorless''' code where every CPU cycle counts! Use '''ON''' to re-enable event checking. Event checking can be turned OFF or ON throughout a program. Commands have no spaces and are '''NOT''' commented out!
* '''QB64''' event $CHECKING is '''NOT''' commented out and there is no space before OFF or ON!
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* [[$INCLUDE]] can be used at the beginning or at the end of program SUB procedures. Reference elsewhere create an [[ERROR Codes|error]]!  
* [[$INCLUDE]] can be used at the beginning or at the end of program SUB procedures. Placing the reference elsewhere creates a QB64 compiler error!  
 
 
* [[$STATIC]] makes all arrays {{KW|STATIC}} or unchangeable in size. Use {{KW|DIM}} only!
 
* [[$STATIC]] makes all arrays {{KW|STATIC}} or unchangeable in size. Use {{KW|DIM}} only!
 
* [[$DYNAMIC]] allows larger arrays that are changeable in size. Use {{KW|REDIM}} for changeable sizes! [[_PRESERVE]] preserves contents.
 
* [[$DYNAMIC]] allows larger arrays that are changeable in size. Use {{KW|REDIM}} for changeable sizes! [[_PRESERVE]] preserves contents.

Revision as of 19:23, 30 June 2011

Qbasic Metacommands are commands that are commented out and start with $.


Syntax:

REM $INCLUDE: 'QB.BI' 'loads a reference file or library
REM $DYNAMIC 'enables resizing of array dimensions with REDIM
REM $STATIC 'arrays cannot be resized once dimensioned
$CHECKING:OFF 'disables QB64 C++ event checking (do not comment or use a space before OFF)


  • Qbasic Metacommands are normally used at the program start and are in effect throughout the program.
  • $CHECKING: OFF should only be used with errorless code where every CPU cycle counts! Use ON to re-enable event checking. Event checking can be turned OFF or ON throughout a program. Commands have no spaces and are NOT commented out!
  • $INCLUDE can be used at the beginning or at the end of program SUB procedures. Reference elsewhere create an error!
  • $STATIC makes all arrays STATIC or unchangeable in size. Use DIM only!
  • $DYNAMIC allows larger arrays that are changeable in size. Use REDIM for changeable sizes! _PRESERVE preserves contents.
  • Metacommands should have their own program line since they are commented out.



See also




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