[Gambas-user] Answer to: "Way to tell if an object is a struct"

[vuott at tutanota.com]

In my opinion TypeOf() function also refers to the constant values present in the list of datatypes identifier numbers, contained in the source file "gambas.h", in which, however, there is no specific identifer number for the Structure.


6 apr 2023, 08:33 da brian at westwoodsvcs.com:

>
> Yes but this does not differentiate a structure from a normal object
>
>
>
> --
>  Thanks
>  Brian G
>
>
> Wednesday, 05 April 2023, 02:22PM -07:00 from Jussi Lahtinen > jussi.lahtinen at gmail.com> :
>
>
>> There is already TypeOf() function. And you can get the class with Object.Type().
>>
>> Jussi
>>
>> On Wed, Apr 5, 2023 at 7:05PM vuott--- via User <>> user at lists.gambas-basic.org>> > wrote:
>>
>>> On this thread
>>>    >>> https://lists.gambas-basic.org/pipermail/user/2023-March/078862.html
>>> Brian G asked, if it were possible to know if an Object is a Structure.
>>> In Gambas source file
>>>    /home/[USER]/gambasdevel/main/share/gambas.h
>>> the numbers of datatypes identifiers are listed.
>>> Therefore, by knowing which number a declared variable belongs to, it is possible to know its data type.
>>> I found a way to know, from the memory address of the variable it is necessary to go back 8 units. Deferencing the Pointer will give the identifier number of the data type of the variable, which consequently will have to be compared with the list above.
>>>
>>> This is my simply code:
>>>
>>> [code]
>>> Public Struct Struttura
>>>   b As Byte
>>>   c As Short
>>> End Struct
>>>
>>> Private id As Struct Struttura
>>>
>>>
>>> Public Sub Main()
>>>
>>> Dim p As Pointer
>>>
>>> p = VarPtr(id)
>>>
>>> Print "Gambas datatype identifier: "; Byte@(p - 8)
>>>
>>> End
>>> [/code]
>>>
>>> It should be noted that in the list of data-type identifier numbers, in particular, the data type Structure is NOT present.
>>> It will be located and reported by my code as an "Object" (number: 16)
>>>
>>> ----[ >>> http://gambaswiki.org/wiki/doc/netiquette>>>  ]----
>>>
>>
>> ----[ >> http://gambaswiki.org/wiki/doc/netiquette>>  ]----
>>

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