Visual Basic Question

On 4/21/2015 4:25 PM, Dave G4UGM wrote: An update on this software/hardware adventure: I have not got a 16 bit capable version of VB4 so I have not started that yet. The thunking advice is quite relevant since the driver talks directly to the ISA card. I am using Visual C++ v1.52 and I am able to write and compile and debug a short piece of code that calls the 16 bit DLL. There is a conflict in the calling argument list though, the manual and the include file Cproto.h say that the directory string is passed as a 'far pointer', however Visual C++ says it must be a near pointer. When I run the code and step thru it using the debugger the first call to acq_open returns a code integer that indicates one of the passed parameters is wrong, don't know which one. I am running under win98se and a companion executable, winvect.exe, is provided to test the DLL out. It works just fine. I run it from a MS-DOS window and when it starts it opens up a window with graphics and plots the data coming from the spectrometer. I used a utility, scanbin.exe, to tell me what the exe and dll files were and it indicates the C++ and winvect.exe are both 'Windows executables 16 bit'. The ISA acquisition card uses DMA is this incompatible inside the debugger?