$ERROR - QB64Official/qb64 GitHub Wiki

The $ERROR metacommand triggers a compilation error.

Syntax

$ERROR MESSAGE

Description

• The 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.

Details

• 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 $IF (or $ELSEIF) block is useless because the program will never compile.

Example(s)

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

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

See Also

• Metacommand
• $IF