call library function using array pointer

[huangwu]

Hi,everybody.

Now I 'm using LV 8.0 to develop a  driver for my  DAQ.Right now I have the  Driver with APIs.So I intend to use the "CallLibralyFuncion" VI .BUt When I test it,the problem appears.

The first function I need to cal is "ScanDevice" function,with the details below:

Inputs:1.CardNumArray,a long type array for storing the returned card IDs,passed by pointer.

            2.CardNumArrayLength,tell the function the size of the array.

Return:The found Card count or error codes.

So I created the VI as show the file I given.

Then the problem appeared:There is always a application error :

It shown me some memory can't not be written.Is it mead I need pass a traditional pointer as in C ,Can the value of the control be used as a buffer to storing the return imformations?Or I need to do other work for calling this function.

Can anyone show me how to use "CallLibralyFuncion" to call my "ScanDevice" function?

[chrisger]

hi there

well, some wild guesses:

- is CardNumArrayLength the number of elements or the number of bytes? if number of bytes pass the number of elements multiplied by 4 to the dll
- try to use a constant U32 array as databuffer
- set the calling convention of the dll to "stdcall (WINAPI)"
- set the execution mode of the dll to "Runin UI thread"

please also post the dll here

[huangwu]

Nice help,sir,thanks a lot.
Actually I just forgot how to spell the word "elements" yestarday,It looks to be some not good :).
The dll file is hardware based and there is a kernel dirver too.So only dll file may show no effect.
Here is the file.

[huangwu]

Oh,my god,I have forgot to tell you that it works fine now.:)
So,thanks a lot again.