$ASSERTS

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The $ASSERTS metacommand enables debug tests with the _ASSERT macro.


Syntax

$ASSERTS
$ASSERTS:CONSOLE


Description

  • This metacommand does not require a comment ' or REM before it. There is no space between the metacommand name, the colon and the CONSOLE parameter.
  • If this metacommand is used in a program and any of the set _ASSERT checkpoints will fail, then the program will stop with an _ASSERT failed error.
  • Detailed error messages passed to the _ASSERT statement will be displayed in the console window, but only if $ASSERTS:CONSOLE is used.
  • The $ASSERTS metacommand serves as main switch to enable debug tests during development. Later you just need to remove the metacommand while leaving all the _ASSERT statements in place for later debugging sessions, they are simply ignored without the metacommand.
  • In newer versions a precompiler flag named _ASSERTS_ is available (see Availability):
    • The flag is one(1) if the program is compiled with $ASSERTS enabled and zero(0) if compiled without it.
    • You may use it to include/exclude debugging related code using precompiler $IF..$ELSE...$END IF blocks.


Availability

  • Since QB64-PE v4.0.0 the precompiler flag _ASSERTS_ indicates the state of $ASSERTS at compile time.


Examples

Example
Adding test checks for parameter inputs in a function.
$ASSERTS:CONSOLE

DO
    a = INT(RND * 10)
    b$ = myFunc$(a)
    PRINT a, , b$
    _LIMIT 3
LOOP UNTIL _KEYHIT
END

FUNCTION myFunc$ (value AS SINGLE)
    _ASSERT value > 0, "Value cannot be zero"
    _ASSERT value <= 10, "Value cannot exceed 10"

    IF value > 1 THEN plural$ = "s"
    myFunc$ = STRING$(value, "*") + STR$(value) + " star" + plural$ + " :-)"
END FUNCTION


See also



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