[Gambas-user] Arrays of Structs - how to - and curious debug message

[Benoît Minisini]

Le 10/06/2021 à 21:10, John Anderson a écrit :
> I've come across an issue I'm trying to solve in Gambas.  I KNOW I'm 
> doing this wrong, and I'm being dumb - but maybe somebody can point the 
> way.  I can't find any more deets online, and the examples about structs 
> are kind of scarce.  But that's not the interesting part...what's 
> interesting is how Gambas decides to NOT flag an error, but maybe I have 
> that wrong too.
 >
 > ...too much text to read at 22 PM
> 

1) Please compress your project archives when you post on the mailing-list.

2) Apparently you didn't read the wiki page on structure declarations.

https://gambaswiki.org/wiki/lang/structdecl

Especially the last paragraph "Arrays of structure".

If you declare that:

Public Struct Foo
   A As Integer
   B As Boolean
   C As String
End

Private $aArray[16] As Struct Foo ' Note the Struct keyword before Foo

Then $aArray will be an array of sixteen Foo structures allocated in one 
slot successively in memory, like the C language does.

For Gambas, $aArray is a special variable of type "array of structure". 
It's not a real array, so you will not have all the methods of the 
standard Array class. It's really for send it to some C code.

Note that a structure declaration can be used like a class with just 
public variables. It's what you did when declaring:

Dim var As New StructureName

In other words:

As StructName -> declare a pointer to a structure allocated like a 
normal object.

As Struct StructName -> embeds a structure directly inside a variable or 
another structure, like C does by default.

So be careful!

If you find the wiki page not clear enough, do not hesitate to fix it.

-- 
Benoît Minisini