Difference between revisions of "Metacommand"

From QB64 Wiki
Jump to navigation Jump to search
imported>Clippy
m
imported>Clippy
m
Line 1: Line 1:
Qbasic '''Metacommands''' are program wide commands that start with $. QB requires them to be commented out.
+
Qbasic '''Metacommands''' are program wide commands that start with $. QBasic requires them to be commented out.
  
  
Line 26: Line 26:
 
* Metacommands are always prefixed with $ and MUST be commented with an apostrophe or [[REM]].
 
* Metacommands are always prefixed with $ and MUST be commented with an apostrophe or [[REM]].
 
* [[$INCLUDE]] is always followed by a colon and the full text code file name is commented on both sides.
 
* [[$INCLUDE]] is always followed by a colon and the full text code file name is commented on both sides.
* [[$STATIC]] and [[$DYNAMIC]] determine the type of arrays the program will use at the start of the program module.  
+
* [[$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.
 +
* Metacommands should have their own program line when commented.  
  
  
 
<center>'''QB64 Metacommands'''</center>
 
<center>'''QB64 Metacommands'''</center>
 
* QB64 does not require a comment or [[REM]] before any Metacommand. '''Do NOT comment QB64 specific Metacommands!'''
 
* QB64 does not require a comment or [[REM]] before any Metacommand. '''Do NOT comment QB64 specific Metacommands!'''
 +
* [[$INCLUDE]] can be used at the beginning or at the end of program SUB procedures. Reference elsewhere create an [[ERROR Codes|error]]!
 
* [[$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!
 
* [[$CHECKING]]: OFF should only be used with '''errorless''' code where every CPU cycle counts! Use '''ON''' to re-enable event checking. Event checking can be turned OFF or ON throughout a program. Commands have no spaces and are '''NOT''' commented out!
* [[$INCLUDE]] can be used at the beginning or at the end of program SUB procedures. Reference elsewhere create an [[ERROR Codes|error]]!  
+
 
* [[$STATIC]] makes all arrays {{KW|STATIC}} or unchangeable in size. Use {{KW|DIM}} only!
+
* '''Do NOT comment or [[REM]] QB64 specific Metacommands! Comment or REM Qbasic ones only!'''
* [[$DYNAMIC]] allows larger arrays that are changeable in size. Use {{KW|REDIM}} for changeable sizes! [[_PRESERVE]] preserves contents.
 
* Metacommands should have their own program line when commented. '''Commenting Metacommands is NOT required in QB64!'''
 
  
  

Revision as of 16:33, 14 August 2012

Qbasic Metacommands are program wide commands that start with $. QBasic requires them to be commented out.


QB == 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


QB64 == Syntax ==

$CHECKING:{OFF|ON} 'disables QB64 C++ event checking (no spaces)
$CONSOLE 'creates a QB64 console window throughout the program
$SCREENHIDE 'hides the QB64 program window throughout the program until $SCREENSHOW is used
$SCREENSHOW 'displays the main QB64 program window throughout the program after $SCREENHIDE has been used


Qbasic Metacommands
  • Qbasic Metacommands are normally used at the program start and are in effect throughout the program.
  • Metacommands are always prefixed with $ and MUST be commented with an apostrophe or REM.
  • $INCLUDE is always followed by a colon and the full text code file name is commented on both sides.
  • $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 when commented.


QB64 Metacommands
  • QB64 does not require a comment or REM before any Metacommand. Do NOT comment QB64 specific Metacommands!
  • $INCLUDE can be used at the beginning or at the end of program SUB procedures. Reference elsewhere create an error!
  • $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!
  • Do NOT comment or REM QB64 specific Metacommands! Comment or REM Qbasic ones only!



See also




Navigation:
Go to Keyword Reference - Alphabetical
Go to Keyword Reference - By usage
Go to Main WIKI Page