another (one-line) C translation request ...

[Bern Ertl]

is this correct? i'm getting an error when i try to access the elements
of the ss_printinfo udt....

short callback ss_printfunc(hdc hdc, short dcommand, short npagenum, long lappdata, lpss_printinfo lpprintinfo);

into :

function ss_printfunc%( byval hdc&, byval dcommand%, byval npagenum%, byval lappdata&, lpprintinfo as ss_printinfo)

more details of my problem in the third party forum : http://www.powerbasic.com/support/pb...ad.php?t=25733



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bernard ertl

[Cecil Williams]

Bern,

Where is your declare statement?????????????? Or did I miss
something here????????

Cheers,
Cecil

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[Bern Ertl]

Hi Cecil, thanks for the reply.

There is no declare statement. The Spread DLL has a print
preview control which can optionally call a callback function
"SS_PRINTFUNC%" which should draw the headers and footers for
the output.

I am defining the SS_PRINTFUNC% function and passing the CODEPTR
to the DLL. The DLL then calls the function as needed when it
prepares a page for output.

The C function declaration which I posted above is the prototype
for the function as listed in the Spread documentation. My
translation (posted above) seems to work (ie. no run-time errors)
as long as I do not try to access the members of the UDT
(lpPrintInfo). When I try to access the UDT, I get illegal action
errors.

Does the CALLBACK keyword have any special significance for the C
function declaration? It seems to me that something is not "jiving"
with the passing of the UDT, but I can't see what it is....



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Bernard Ertl

[Lance Edmonds]

Bern, have you asked FarPoint?

Apparently, they have a set of PowerBASIC headers all ready to be used, but you have to ask them directly.

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

[Bern Ertl]

Hi Lance,

Yes, I sent them an e-mail this morning. I asked them to
verify the UDT structure and the parameter passing methods for
the callback call.

They are not up to speed yet on PowerBASIC, so I don't expect much
help from from them in debugging this error.

I was the one who pushed Farpoint into handling the PB translated
header file. What I'm trying to do right now is unrelated to the
header file (assuming that the UDT is correct).

The Farpoint docs list a prototype for the callback function which
needs to be created in the user's app (using PB in my case). Their
prototype claims that their DLL will pass a pointer to the UDT as the
last parameter. I've tried receiving this pointer three different ways:

1) FUNCTION SS_PRINTFUNC%( ..., lpPrintInfo AS SS_PRINTINFO)

2) FUNCTION SS_PRINTFUNC%( ..., BYVAL ptrPrintInfo AS SS_PRINTINFO PTR)

3) FUNCTION SS_PRINTFUNC%( ..., BYVAL ptrPrintInfo AS DWORD)
DIM lpPrintInfo AS SS_PRINTINFO PTR
lpPrintInfo = ptrPrintInfo

With all three attempts, I get the same result. Everything will work without
errors until I try to access a member of the SS_PRINTINFO udt.

Any ideas?



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Bernard Ertl

[Ian Cairns]

Bern,
Since you asked for ideas, I might take this approach.
1. Since what is being returned is an address, accept it as a dword/long.
2. Create a byte pointer and assign the returned address to it.
3. Scan the returned address byte-by-byte for the length of the SS_PRINTINFO structure.
4. Transfer the bytes to a string.
5. Compare the contents with what you expect to receive.
6. You can always LSET the string contents into a SS_PRINTINFO variable.

Happy Debugging,

[This message has been edited by Ian Cairns (edited May 29, 2001).]

[Lance Edmonds]

Just a guess, but are you sure of the alignment that the UDT using? Could it be 8-byte alignment?

Is a valid address for this UDT being received? Can you look at the 1st 4 or 8 bytes of the pointer target or does that trigger a GPF too?

If so, then that suggests a parameter order problem, although that looks ok (CALLBACK=SDECL/STDCALL).

Bizarre!



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

[Lance Edmonds]

Ian has a similar idea to me (we posted at approx the same time!) - look at the target and see if you can figure out the correct UDT format/alignment.

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

[Bern Ertl]

Ian, Lance, et al,

Thanks for the help. I did as you suggested and checked out what
was being received.

Apparantly, the DLL calls the callback function four times for every
page of output. One time each for each of the four commands:

1) Set header length
2) Set footer length
3) Draw header
4) Draw footer

When calling to set the header / footer length, the DLL is passing a
NULL pointer for the UDT. So, I've got it working now using the following:

FUNCTION SS_PRINTFUNC%( BYVAL hDC&, BYVAL dCommand%, BYVAL nPageNum%, BYVAL lAppData&, BYVAL addrPrintInfo AS DWORD)


   LOCAL hCurrentDC&, CurrentRect AS RECT
   LOCAL ptrPrintInfo AS SS_PRINTINFO PTR
   LOCAL szTemp AS ASCIIZ * 260
   DIM hSpreadFont AS LOCAL LONG    'or DWORD
   DIM tFont       AS LOCAL LOGFONT 'Start with a stock font


   IF addrPrintInfo > 0 THEN
      ptrPrintInfo = addrPrintInfo
      IF @ptrPrintInfo.fIsPreview <> 0 THEN
         'Output is Preview Control
         hCurrentDC& = hDC&
         CurrentRect = @ptrPrintInfo.RectPreview
         'Get Arial 10 pt
         hSpreadFont = SSGetFont( @ptrPrintInfo.hWndSpread, 1, 1) 'Get Spread font handle
         GetObject hSpreadFont, LEN(tFont), BYVAL VARPTR(tFont) 'Get Spread font info
         tFont.lfHeight = -MulDiv( 10, GetDeviceCaps( hCurrentDC&, %LOGPIXELSY), 72)
         hMyFont = CreateFontIndirect(tFont) 'Make copy of Spread font with my changes
      ELSE
         'Output is Printer Device
         hCurrentDC& = @ptrPrintInfo.hDCPrinter
         CurrentRect = @ptrPrintInfo.RectPrinter
      END IF
   ELSE
      'Output is unknown - determine header / footer length
      hCurrentDC& = hDC&
   END IF


   SELECT CASE dCommand%
      CASE %SS_PRINTCMD_HEADERLEN
         FUNCTION = 800             
      CASE %SS_PRINTCMD_FOOTERLEN
         FUNCTION = 120
      CASE %SS_PRINTCMD_PRINTHEADER
         SelectObject hCurrentDC&, hMyFont
         szTemp = "Is this working?"
         DrawText hCurrentDC&, szTemp, -1, CurrentRect, %DT_LEFT OR %DT_NOPREFIX OR %DT_WORDBREAK
         DeleteObject hMyFont
      CASE %SS_PRINTCMD_PRINTFOOTER
         DeleteObject hMyFont
   END SELECT


END FUNCTION

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Bernard Ertl



[This message has been edited by Bern Ertl (edited May 29, 2001).]

[Cecil Williams]

Bern,

Wow, something else. As a last resort try this:

DIM lpPrintInfo as SS_PRINTINFO PTR

call the function as:

FUNCTION SS_PRINTFUNC%( BYVAL hDC&, BYVAL dCommand%, BYVAL nPageNum%, BYVAL lAppData&, lpPrintInfo)

See if this works. Good luck!!!

Cheers,
Cecil

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