How the following C code translate to xBase++?
dpcbs.size = sizeof(DPcbs);
dpcbs.connectedCB = ConnectedEvent;
dpcbs.disconnectedCB = DisconnectedEvent;
dpcbs.docCompleteCB = DocCompleteEvent;

Thanks,
-Itai

hi,

> How the following C code translate to xBase++?
> dpcbs.size = sizeof(DPcbs);

you need the Structure of dpcbs else you cant "calculate" SizeOf()

dpcbs an array?  String?  Something else?

hi,

> dpcbs an array?  String?  Something else?

No, as i say Structure ... like a DBF

Member ( like Field ) are

connectedCB
disconnectedCB
docCompleteCB

i recommend to use Ot4xb to build your own Structure

Jim,
Xbase++ recognizes Number, String, Date, Array, Codeblock, object,
etc.  But not Structure.  What variable is Structure (I need to pass
it as a parameter to a DLL call)?

Hi.
Good day.
In Xbase++ it has 
C:\Users\Beling\Documents\Xbase++\source\samples\bap\basics that may to 
help you.

Fraternally
Beling

On 05/11/2020 05:26, Itai Ben-Artzi wrote:
> Jim,
> Xbase++ recognizes Number, String, Date, Array, Codeblock, object,
> etc.  But not Structure.  What variable is Structure (I need to pass
> it as a parameter to a DLL call)?
>

Thank you, Carlos!
I understand it now.
BTW, is seems a structure is just a multi-dimential array.

Agian, thank you for leading me to this sample.

-Itai

hi,

> I understand it now.
> BTW, is seems a structure is just a multi-dimential array.

Carlos have point to BAP.

it does work with"simple" Structure but if you have more complicate 
Structure you got stuck with BAP
thats why i point to Ot4xb while it have a lot of Structure already in 
winapi_CommonStructures.cpp

Itai,

>I understand it now.
>BTW, is seems a structure is just a multi-dimential array.

Actually, a Structure is more like an Object rather than an Array, and in 
Xbase++ you will have to treat it basically like a binary string, when using 
it (as aa parameter) in DLL calls.

BAP is a simple way to handle structures in Xbase++ and OT4Xb has a more 
comprehensive way to do the same. Actually, Alaska recently added some 
additional Structure and Union functionality in the "XppRt2.ch" file. This 
is mainly used in several of the Assets: SecSigner API, Swissbit TSE API, 
and Telephony API (TAPI).

You need to know the structure definition of the "DPcbs" structure to assign 
the right values to its properties. Based on the names of those properties, 
it seems that they may be callback addresses for event-processing functions 
in your Xbase++ code.

Hope that helps,

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Andreas,
Back to my original question:
How to create the following (c) structure is xBase?

dpcbs.connectedCB = ConnectedEvent;
dpcbs.disconnectedCB = DisconnectedEvent;
dpcbs.docCompleteCB = DocCompleteEvent;

-Itai

Itai,

>Back to my original question:
>How to create the following (c) structure is xBase?

>dpcbs.connectedCB = ConnectedEvent;
>dpcbs.disconnectedCB = DisconnectedEvent;
>dpcbs.docCompleteCB = DocCompleteEvent;

Without documentation as to the layout of this structure, that can't be 
answered. Show us the documentation (or at least the entire source code) 
that describes this structure.

Specifically, your original post included: 

dpcbs.size = sizeof(DPcbs);

Are there other properties that you haven't mentioned?

Also, what variable type(s) are the three *CB properties? That basically 
determines what values you assign (and how) and what the "dpcbs.size" 
value should be.

Without that information, nobody can tell you (for sure).

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Andreas,
Attached is the C source code and
the documentation from Digital Check API.

Itai,

Thanks for the documentation. I have attached some example code for using 
this structure with BAP. You could also use OT4Xb to do something similar.
Of course, I have no idea if this will actually work, as I can't test it 
here without the required software and hardware environment.

Hope that helps anyway,

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Thank you, Andreas!
I'll look at this sample.

-Itai

Where is the BAP documentation?

Itai,

>Where is the BAP documentation?

I don't think there is any documentation besides a little text file that was 
on the 1.90.331 CD. I have just read it, and at the very end, it basically 
says that you can't use BAP for your particular structure, as BAP only 
supports a single callback per thread, while your structure requires 21 of 
them. I was worried that this would be case, as the return value for the 
BaCallback() functions were all the same.

That leaves you (possibly) with OT4Xb. I suggest you asked Pablo if he can 
help you with this. You could either post in the ot4xb newsgroups or email 
him directly. The newsgroups are available here:
* http://news.Xb2.net   (web interface)
* nntp://news.Xb2.net   (news reader)
* nntp://news.xbwin.com (news reader)

Be prepared that what you want to do might actually not be possibly with 
Xbase++, though.

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Andreas,
Is STRUCTURE a type of var not supported by xBase++?

Itai,

>Is STRUCTURE a type of var not supported by xBase++?

You can deal with structures in Xbase++ in several different ways, including 
BAP and OT4Xb, but your specific issue aren't structures per se, but the 
function pointers for callbacks that your structure requires. 

With BAP, Xbase++ can handle only one function pointer per thread, and I 
don't know if OT4Xb can handle more than one, but your particular structure 
requires 21 function pointers for 21 different callback functions.

So, if Pablo can do some of his C magic to allow you to manage 21 different 
function pointers for your callbacks in that structure using Xbase++ with 
OT4Xb, then you shouldn't have a problem. But if he can't, then I don't 
think that you can use this particular API with Xbase++.

Hope that helps,

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Andreas,
While the sample program uses a single structure as reference to all
callbacks, each function API call requires a single callback. Thus,
either BAP or OT4xb can be used.  I still like to know what type of
var is this "structure" and whether or not it can be referenced by
xBase++.

Thanks,
-Itai

Itai Ben-Artzi wrote in news:3e3uqf1nd7fsr9h6f5vt0do7gtkasmavv8@4ax.com:

> While the sample program uses a single structure as reference to all
> callbacks, each function API call requires a single callback. Thus,
> either BAP or OT4xb can be used.  I still like to know what type of
> var is this "structure" and whether or not it can be referenced by
> xBase++

A C structure is basically a string of binary characters. For example a 
simple structure consisting of 2 32-bit integers would be string 8 bytes 
log. The first 4 bytes would be the 1'st INT and the next 4 bytes would be 
the 2'nd INT. Structures can become quite complex when you consider that 
some of the elements may be pointers to other memory locations.

Although in theory, you can create the C structures in Xbase++ by 
assembling the individual elemets (eg. using i2bin / l2bin,...), you would 
need to 'lock' the string when passed to a C lib so that the Xbase++ 
garbage collector does not touch it while in use by the external lib.

Best regards,
Boris Borzic

http://xb2.net
http://sqlexpress.net
industrial strength Xbase++ development tools

Itai,

>While the sample program uses a single structure as reference to all
>callbacks, each function API call requires a single callback. Thus,
>either BAP or OT4xb can be used.

The problem is that it isn't that simple to call Xbase++ functions from 
outside an Xbase++ program. Your structure needs 21 function pointers -- 
basically the memory addresses of the corresponding Xbase++ functions -- 
and that isn't something that is available in basic Xbase++. With BAP, 
Alaska added a way to create a single function pointer per thread that 
can be called from outside the Xbase++ program, and with OT4Xb you can 
create apparently something similar with the CallBack Compiler, using 
specially created obj files. I have never used OT4Xb for that purpose, 
so I don't know if it is possible to create those 21 callbacks for your 
structure using this method.

>I still like to know what type of var is this "structure" and whether or 
>not it can be referenced by xBase++.

C Structures are user-defined data types, very similar to Classes, which 
basically describe a section of memory and how its content should be 
interpreted by a program. Structures are binary data -- a binary string 
if you will -- whose parts can be interpreted in many different ways. 

Structures contain fields or members (just like Classes or Objects have 
Properties or Instance Variables), each of which has a data type as well 
as a name. The data type describes the length of the binary data -- how 
many bits or bytes it comprises -- and how its value should be interpreted.

For example as individual or multiple characters or bytes, containing 
integers, floats or even pointers to other values, like strings or other 
variables in other memory locations, including pointers to functions. That 
binary data can be passed around and possibly manipulated by different parts 
of an application or even external applications or DLLs.

The main problem is that Xbase++ is a high-level programming language with 
little support for low-level memory access, which other languages, like C, 
C++, C#, or even Python have. So, even though you can create and manipulate 
C structures in Xbase++, it isn't straight forward or easy, and some of the 
low-level access to things like the memory address -- or entry point -- of 
functions and their corresponding calling convention format -- so called 
Function Pointers -- are just not available directly.

You might want to google "C Structures" and/or "Function Pointers" for more 
technical details and also download Pablo's CallBack Compiler from here:

	https://drive.google.com/drive/folders/0B9dUp4e-Y5DvaFcxMFpWSktQNXc

Hope that helps,

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC

Andreas,
Where can I find this OT4XB?

Itai,

>Where can I find this OT4XB?

You can download the latest version of OT4Xb (1.6.4.96) from here:

	https://drive.google.com/drive/folders/1rbBWb-ivDZFEnZ4urZDgmWZDVLqNHJpf

But you really need Pablo's CallBack Compiler, too, from here:

	https://drive.google.com/drive/folders/0B9dUp4e-Y5DvaFcxMFpWSktQNXc

Hope that helps,

Andreas

Andreas Gehrs-Pahl
Absolute Software, LLC

phone: (989) 723-9927
email: Andreas@AbsoluteSoftwareLLC.com
web:   http://www.AbsoluteSoftwareLLC.com
[L]:   https://www.LinkedIn.com/in/AndreasGehrsPahl
[F]:   https://www.FaceBook.com/AbsoluteSoftwareLLC