Need help with a struct that i need to pass to a dll

Question

I have just received an SDK from a third party vendor.
I need to pass a struct to a dll in order to use our measuring arm.
Here's the definition of the struct
struct vOpenInfo
        int                 nFuncType;       // = DLL_OPEN_CMM (or 1)
        HWND         hwnd;
        WCHAR      sSaveDir[128];
        void             (*HelpCallBack)();
Here's the definition of the only function that I can access from the DLL
int CmmSpecific(void *)
From what I understand the CmmSpecific function use the pointer on the structure to know what I want to do.
The only problem, is that I need to transform LabVIEW data onto that type of struct.
Does anybody have an idea how can I do it?
Thanks in advance

Answer 1

Julien Tozzi wrote:
I have just received an SDK from a third party vendor.
I need to pass a struct to a dll in order to use our measuring arm.
Here's the definition of the struct
struct vOpenInfo
        int                 nFuncType;       // = DLL_OPEN_CMM (or 1)
        HWND         hwnd;
        WCHAR      sSaveDir[128];
        void             (*HelpCallBack)();
Here's the definition of the only function that I can access from the DLL
int CmmSpecific(void *)
From what I understand the CmmSpecific function use the pointer on the structure to know what I want to do.
The only problem, is that I need to transform LabVIEW data onto that type of struct.
Does anybody have an idea how can I do it?
The previous post is basically correct but one thing catches my eye here and that is the fourth element in the structure which is a function pointer. The LabVIEW system can't really deal with this without quite some involved programming I would not recommend anyone to try without some very good C programming knowledge.
So if the API description doesn't tell you that it is valid to just pass in here a NULL value to disable the callback, writing a wrapper DLL that translates this into a more LabVIEW friendly interface is by far easier to do.
Rolf Kalbermatter
Message Edited by rolfk on 01-11-2007 10:09 AM
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions