🚀 go-pugleaf

On Sun, 21 Dec 1997 13:33:21 +0100, Ruediger Spindler
<spindler@on-line.de> wrote:

>Has anyone experiences with EZTWAIN.DLL and vdbase and could me give
>some hints
>how to get this working???

Hi Ruediger,

I did not look through your code, but here is a code- snippet which
works for me:

Procedure Scan_OnClick
PARAM oFormHwnd,cFieldId 
&&cFieldId contains qualifier (BINARY or  OLE)+" "+FieldName
PRIVA TwInt,iResult,FiName
IF TYPE('TWAIN_AcquireNative')<>'FP'
   EXTERN CINT TWAIN_AcquireNative(CINT,CINT) EZTWAIN.DLL
ENDIF
EXTERN CINT TWAIN_WriteNativeToFilename(CINT,CSTRING) EZTWAIN.DLL
EXTERN CINT TWAIN_FreeNative(CINT) EZTWAIN.DLL
FiName='TMP.BMP'
TwInt=TWAIN_AcquireNative(oFormHwnd,0)
iResult=TWAIN_WriteNativeToFilename(TwInt,FiName)
iResult=iResult+TWAIN_FreeNative(TwInt)
IF iResult=0
    REPL &cFieldId. FROM &FiName
    *FORM.IMAGECC.DataSource="FILE "+FiName
ENDIF
RELEASE DLL EZTWAIN.DLL
RETURN

Ruediger Spindler wrote in message <349D0C91.9C60FFAB@on-line.de>...
>Hello all vdbase programmers,
>I try to access a TWAIN-compatible scanner from vdbase 5.5, using the
>EXTERNal DLL EZTWAIN 1.06 and 1.07, but getting problems by passing
>the filename to one of it's functions. All other functions are working
>well.
>The code I tried:
>
>***************************************************************************
****
>
>EXTERN CINT TWAIN_AcquireToFilename( CHANDLE, CSTRING ) EZTWAIN.DLL
>EXTERN CINT MessageBox( CHANDLE, CSTRING, CSTRING, CWORD) USER.EXE
>
>      tempfile = "SCANTEMP.BMP"
>      MessageBox( 0, "This file will be created", tempfile, 0 )
>      scanres = TWAIN_AcquireToFilename( 0, tempfile )
>      if scanres > 0                              && (will always fail
>with -2 = illegal filename)
>***************************************************************************
****
>
>Visual dBASE uses:
> - pascal calling convention
> - 16bit DLLs only
> - CHANDLE = 16bit WORD
> - CSTRING = zero terminated char far *
>So everything should be OK...
>
>The problem on this:
>The external Windows DLL-Func "MessageBox" works OK, but the EZTWAIN
>DLL-Func "TWAIN_AcquireToFileName" seems to misunderstand the filename
>and uses garbage-strings (or NULL or empty) instead and so fails to
>create the file...

You might try prototyping the function like this:

 EXTERN CINT TWAIN_AcquireToFilename( CHANDLE, CPTR ) EZTWAIN.DLL

Append a null to the string parameter:

      tempfile = "SCANTEMP.BMP"+chr(0)
      MessageBox( 0, "This file will be created", tempfile, 0 )
      scanres = TWAIN_AcquireToFilename( 0, tempfile )
____
Bowen Moursund
bowenNOSPAM@nerds.com
http://www.mindspring.com/~bowenm/datatech.htm

Thanks for all hints...
finally I fixed the problem: it wasn't within my code but is a small bug
within the EZTWAIN.DLL library where the function TWAIN_AcquireToFilename
has a wrong definition using a NEAR pointer to the string instead of using a
FAR pointer. I hope, spike will fix it for the next release...
This bug is only in this one routine so I worked around it by using lower level
functions which are working perfectly alright.
so merry x-mas to all
Ruediger

Ruediger Spindler wrote:

> Hello all vdbase programmers,
> I try to access a TWAIN-compatible scanner from vdbase 5.5, using the
> EXTERNal DLL EZTWAIN 1.06 and 1.07, but getting problems by passing
> the filename to one of it's functions. All other functions are working
> well.
> The code I tried:
>
> *******************************************************************************
>
> EXTERN CINT TWAIN_AcquireToFilename( CHANDLE, CSTRING ) EZTWAIN.DLL
> EXTERN CINT MessageBox( CHANDLE, CSTRING, CSTRING, CWORD) USER.EXE
>
>       tempfile = "SCANTEMP.BMP"
>       MessageBox( 0, "This file will be created", tempfile, 0 )
>       scanres = TWAIN_AcquireToFilename( 0, tempfile )
>       if scanres > 0                              && (will always fail
> with -2 = illegal filename)
> *******************************************************************************
>
> Visual dBASE uses:
>  - pascal calling convention
>  - 16bit DLLs only
>  - CHANDLE = 16bit WORD
>  - CSTRING = zero terminated char far *
> So everything should be OK...
>
> The problem on this:
> The external Windows DLL-Func "MessageBox" works OK, but the EZTWAIN
> DLL-Func "TWAIN_AcquireToFileName" seems to misunderstand the filename
> and uses garbage-strings (or NULL or empty) instead and so fails to
> create the file...
>
> Has anyone experiences with EZTWAIN.DLL and vdbase and could me give
> some hints
> how to get this working???
> Thanks in advance
> Ruediger Spindler