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Metacommand

Samuel Gomes edited this page Nov 8, 2022 · 1 revision

Metacommands are program wide commands that start with $.

QBasic/QuickBASIC - Legacy metacommands

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

Description

  • QBasic Metacommands are normally used at the program start and are in effect throughout the program.
  • QBasic 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.
  • $DYNAMIC allows larger arrays that are changeable in size at runtime.
  • $STATIC makes all arrays unchangeable in size.
  • QBasic metacommands should have their own program line because they are commented.

QB64 metacommands

Syntax

$ASSERTS:CONSOLE

$CHECKING{OFF|ON} 'disables QB64 C++ event and error checking (no spaces)

$COLOR 'adds named color CONSTantes to a program

$CONSOLE 'creates a QB64 console window throughout the program

$DEBUG enables debugging features, allowing you to step through your code line by line

$ERROR MESSAGE triggers a compilation error MESSAGE.

$EXEICON:'iconfile.ico' 'embeds an .ICO file into the final executable (Windows only)

$IF ... $ELSEIF ... $ELSE ... $END IF 'precompiler directive

$LET variable = expression

$RESIZE:{ON|OFF|STRETCH|SMOOTH} 'determines if re-sizing of the program screen by the user is allowed

$SCREENHIDE 'hides the QB64 program window throughout the program

$SCREENSHOW 'displays the main QB64 program window

$VERSIONINFO:key=value 'embeds version info metadata into the final executable (Windows only)

$VIRTUALKEYBOARD:{ON|OFF} 'DEPRECATED keyword

Description

  • $ASSERTS:CONSOLE Enables debug tests with the _ASSERT macro.

  • $CHECKING{OFF|ON} 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.

  • $COLOR adds named color CONSTantes to a program.

  • $CONSOLE creates a console window which can be turned off later with _CONSOLE OFF.

  • $DEBUG enables debugging features, allowing you to step through your code line by line.

  • $ERROR MESSAGE triggers a error MESSAGE only during your program compilation.

  • $IF ... $ELSEIF ... $ELSE ... $END IF allows selective inclusion of code in the final program.

  • $LET variable = expression sets a precompiler variable to a value.

  • $RESIZE:{ON|OFF|STRETCH|SMOOTH} allows a user to resize the program window. OFF is default.

  • $SCREENHIDE hides the QB64 program window throughout the program until $SCREENSHOW is used.

  • $VERSIONINFO:key=value embeds version info metadata into the final executable (Windows only).

  • Do not comment out with ' or REM QB64-specific metacommands.

See Also

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