Question How to receive a handle in an External Procedure

[Estevan]

Hello guys.

I'm calling an external procedure (WEBTAEncoderLib.dll) to encode a bank file (bank name: Bradesco, from Brazil).

In one of the methods to encode the file, I receive a handle value that I need to pass to another method.
Like this:
Method "fInitEncoder" return me a Handle.
This returned handle, I have to pass to the method "fWritedata".

My question is: how can I receive this "handle"? How is the datatype in Progress 4GL to a handle in an External Procedure?



Sorry about the documentation, but it just in Portuguese (because it's a Brazilian bank haha)

Thanks in advance!!

 

[Cecil]

It's been awhile since I've done any DLL stuff, but I belive that handles can be stored a LONG data types.

Example:

PROCEDURE fInitEncoder EXTERNAL "WEBTAEncoderLib.dll":
DEFINE input PARAMETER p-FileName AS Character.
DEFINE input PARAMETER p-Director AS Character.
DEFINE input PARAMETER p-KeyAS Character.
DEFINE input PARAMETER p-ErrOmessage AS Character.
DEFINE RETURN PARAMETER p-Return AS LONG.
END PROCEDURE.

I might have mixed some parameters but hopfully you get the gist.

RETURN-VALUE-DLL-TYPE attribute

 

[Osborne]

As Cecil posted, I think LONG is what you are looking for. I have rarely interacted with DLL's but I have seen examples like these:

PROCEDURE GetSysColor EXTERNAL "user32.dll":
  DEFINE INPUT  PARAMETER nIndex    AS LONG.
  DEFINE RETURN PARAMETER iWinColor AS HANDLE TO LONG.
END.

PROCEDURE file_search EXTERNAL "dirsrch.dll":
 DEFINE INPUT        PARAMETER Search-Dir   AS HANDLE TO CHARACTER.
 DEFINE INPUT        PARAMETER File-Spec    AS HANDLE TO CHARACTER.
 DEFINE INPUT-OUTPUT PARAMETER File-List    AS MEMPTR.
 DEFINE INPUT        PARAMETER List-Size    AS LONG.         
 DEFINE OUTPUT       PARAMETER Missed-Count AS HANDLE TO LONG.
 DEFINE RETURN       PARAMETER Error-Val    AS SHORT.        
END PROCEDURE.

DEFINE VARIABLE iProcess      AS INTEGER     NO-UNDO.
DEFINE VARIABLE iWow64Process AS INTEGER     NO-UNDO.
DEFINE VARIABLE iResultValue  AS INTEGER     NO-UNDO.

RUN GetCurrentProcess( OUTPUT iProcess ).
RUN IsWow64Process( INPUT iProcess,
                    INPUT-OUTPUT iWow64Process,
                    OUTPUT iResultValue ).

PROCEDURE GetCurrentProcess EXTERNAL "kernel32.dll":
   DEFINE RETURN PARAMETER iProcess AS LONG.
END.

PROCEDURE IsWow64Process EXTERNAL "kernel32.dll":
   DEFINE INPUT        PARAMETER iProcess      AS LONG.
   DEFINE INPUT-OUTPUT PARAMETER iWow64Process AS HANDLE TO LONG.
   DEFINE RETURN       PARAMETER iResultValue  AS LONG.
END.

 

[Estevan]

Thanks for all replies!!
It worked for me receiving as a "INT64". But now I have a new problem: send a parameter as a "byte".

Considering the OpenEdge documentation, is not possible to receive/send a parameter as "system.byte".

Has anyone ever seen this before?

 

[Cecil]

you might be able to get away with an integer data type.

do you have any more documentation you can share of what you’re trying to achieve?

 

[Estevan]

I tried this before, but isn't work.
And I don't have any other documentation, just that in Portuguese:


There is an exemple in "C", but didn't help me:
int fWriteData(void *handle, const BYTE *data, const int dataLen, char *msgErro)

 

[dimitri.p]

for a BYTE data use LONG
for a BYTE *data use CHAR or MEMPTR