$ERROR: Difference between revisions

Revision as of 12:37, 28 March 2023

The $ERROR metacommand triggers a compilation error.

$ERROR message

This metacommand does not require a comment ' or REM before it.
message is any text. Quotation marks are not required.
When QB64 tries to compile an $ERROR metacommand a compilation error is triggered and message is shown to the user. This is useful in $IF blocks.
If there is a particular situation where you know your program will not work properly, you can prevent the user compiling and give them a helpful error message instead by checking for the condition with $IF.
An $ERROR directive not inside an conditional $IF (or $ELSEIF) block is useless because the program will never compile in that case.

$IF VERSION < 2.1 $IF WINDOWS = 0 THEN
    $ERROR Requires Windows QB64 version 2.1 or above
$END IF

Output (IDE Status Area): Compilation check failed: REQUIRES WINDOWS QB64 VERSION 2.1 OR ABOVE on line 2 (assuming your version of QB64 doesn't meet those requirements).

@@ Line 16: / Line 16: @@
 {{PageExamples}}
 {{CodeStart}}
-{{Cl|$IF}} VERSION < 2.1 OR WINDOWS = 0 THEN
+{{Cm|$IF}} {{Text|VERSION|#55FF55}} < {{Text|2.1|#F580B1}} {{Cm|OR|$IF}} {{Text|WINDOWS|#55FF55}} = {{Text|0|#F580B1}} {{Cm|THEN}}
-     {{Cl|$ERROR}} Requires Windows QB64 version 2.1 or above
+     {{Cm|$ERROR}} Requires Windows QB64 version 2.1 or above
-{{Cl|$END IF}}
+{{Cm|$END IF}}
 {{CodeEnd}}
 ;Output (IDE Status Area):Compilation check failed: REQUIRES WINDOWS QB64 VERSION 2.1 OR ABOVE on line 2 (assuming your version of QB64 doesn't meet those requirements).