🚀 go-pugleaf

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