Bug or Feature with Arrays?

[Torte Torsten]

I have found a strange behavior.

If i declare an empty Array and write code that try to access
an element of that array, but have no code wich dimensions that
array the compiler will not compile my code with error 461.
Should it not be better a runtime error instead of a compiler error?

Example

Global MyArray() as MyType

'Remove the comments in PBMain and the code will compile
Function PBMain ....
'Redim MyArray(0) as MyType
'Erase MyArray
Msgbox MyArray(1).MyTypeMember
End Function

... a lot of other functions

Regards,

Torsten


------------------

[Gregery D Engle]

Torte,

Your correct. If you wish to access a dynamic array you will
need to do it this way:

#compile exe
global sample() as string

function pbmain() as long
   redim sample(0 to 0)
   slickexamplesub sample()
   msgbox sample(1)
   msgbox sample(2)
end function

------------------
-Greg

[Lance Edmonds]

Referencing an array outside of it's bounds at runtime is one of the best ways to trigger a GPF. Referencing an array that has been erased is another good way.

PB/DLL and PB/CC do not support the DOS Basic "auto-dim" for undimensioned arrays.

Essentially, the compiler detected that your array had not been dimensioned at all, and this would have caused a definite runtime failure. It correctly flagged the error.

Note that unless you use #DEBUG ERROR ON, PowerBASIC does not validate array subscript values at run-time - such range validations are the responsibility of the programmer.

In summary (and IMHO), I'd much rather find a problem with an undeclared array at compile-time rather than have a customer report a show-stopping run-time error from the field.




------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>