Creating a DLL in LabVIEW containing a function using pointer to pointer

[FaSch]

Hi!

I´m facing the problem to create a DLL from LabVIEW containing the following C-function:

functionF(structS** arrayA) ,

where:

structS is a struct of various data-types (e.g. int)

arrayA is an C-array of structS

How can this be done? Any ideas?

Thank you in advance for your support

[waldemar.hersacher]

This cannot be done in LabVIEW. LV doesn't have the data type "Pointer" as C has.
The only workaround I can think of is to use an array of strings in LV and in the interface define the parameter as "by reference". In LV you have to typecast the wire with the string to a cluster withthe layout of structS.
As far as I know an array of strings is represented as an array of pointer to strings. This is because strings are variable in length and therefore LV uses this method storing the pointers to the strings in the array and not the elements as usual.
You have to read the document about memory and data types of LabVIEW. In elder versions this was in the LabVIEW Bookshelf but I haven't found it in short in the newer version.

[dhiraj03416]

but if such function is written in C then can it be called in Labview??
thanks

[FaSch]

Thanks for your answer waldemar!

I like the idea with array of structs - sounds logical for me.

The problem is i can not fix the typecasts i would need. How should cast a cluster of strings and ints into an string? I think that´s not possible...

[FaSch]

sorry,

"array of strings" of course

[FaSch]

There´s no way doin´ this without a wrapper-dll. That´s what frightened me since the beginning. Anyway - no choice...

Hope this comes to a good end