Assertkeyword

Debugging macro that halts program execution if an expression is evaluated to 0 (false).

Syntax

#define Assert(expression) If (expression) = 0 Then : fb_Assert( __FILE__, __LINE__, __FUNCTION__, #expression ) : End If

Parameters

Name		Description
`expression`		Any valid conditional/numeric expression. If
`expression`		evaluates to `0` (i.e. "false"), execution is halted.

Description

The Assert macro is intended for use in debugging and works only if the -g or -eassert option is specified on the fbc command line. In this case it prints an error message and stops the program execution if expression evaluates to 0

.



Its normal use is to check the correct value of the variables or expressions during debugging.



If

-g and -eassert are not passed to fbc, the macro does not generate any code, and has no effect.

Note: If an Assert fails while the program is in a graphics Screen (Graphics), the error message will not be visible as it will be printed to the graphics screen, which will be closed immediately after.

Remarks

Usage



Assert( expression )

Dialect Differences

Not available in the -lang qb dialect unless referenced with the alias __ASSERT.

Differences from QB

New to FreeBASIC

Example

Sub foo

 Dim a As Integer

 a=0

 Assert(a=1)

End Sub



foo 



'' If -g or -eassert is used, this code stops with: test.bas(3): assertion failed at FOO: a=1

Reference

Documented in KeyPgAssert.html