$NOPREFIX: Difference between revisions

Revision as of 20:30, 15 June 2022

The $NOPREFIX metacommand allows all QB64 functions and statements to be used without the leading underscore (_).

QB64-specific keywords are by default prefixed with an underscore, in order to differentiate them from legacy keywords inherited from QBasic/QuickBASIC 4.5.
The convention exists in order to allow older code to be loaded and compiled in QB64 without naming conflicts with existing variables or constants.
If you are writing new code with QB64, and not importing code from QBasic/QuickBASIC 4.5, $NOPREFIX allows you to reduce typing by not having to use underscores in modern keywords.
SUB _GL still must be prefixed.
When $NOPREFIX is used, QB64 keywords can be used both with or without the leading underscore, so that both _DISPLAY and DISPLAY are valid in the same program, for example.
$NOPREFIX must be the first non-comment and non-whitespace line in a program.
- Since QB64 2.0 respectively QBPE 0.5 $NOPREFIX can be placed anywhere in a program.

@@ Line 12: / Line 12: @@
 * '''SUB _GL''' still must be prefixed.
 * When [[$NOPREFIX]] is used, QB64 keywords can be used both with or without the leading underscore, so that both [[_DISPLAY]] and [[_DISPLAY|DISPLAY]] are valid in the same program, for example.
-* [[$NOPREFIX]] can be placed anywhere in a program.
+* [[$NOPREFIX]] must be the first non-comment and non-whitespace line in a program.
+** Since QB64 2.0 respectively QBPE 0.5 [[$NOPREFIX]] can be placed anywhere in a program.