struct with pointer

[lp1]

Hello I need to interface with a DLL with the folowing structure:

extern "C" {

struct IDSTRUCT
{
UINT8 code[2];
UINT8 signature[8];
UINT8 revision [4];
};

R2DLL_API BOOL R2DLL_ReadFirmwareHeader (UINT16 port, struct IDSTRUCT* pStoreAdr);

Is there a way to implement this with clusters in labVIEW?

Thanks in advance

[rsam]

Hi,

the way to go isn't the easiest! Define an U8 array of lets say 50 elements( Contains al necessary bytes + an extra 4), cast it to a string and wire it to the dll terminal(= C String Pointer). The information retrieved is mangled in the string return string. Simply do some byte manipulation ( big/little endian enc.) and you'll have your info.

LabView handles strings like { u32 length, u32* pointer). Refering to above the length long introduces the extra 4!.

Try It

Ruud

[rolfk]

lp1 wrote:

> Hello I need to interface with a DLL with the folowing structure:
>
> extern "C" {
> struct IDSTRUCT {
> UINT8 code[2];<br>
> UINT8 signature[8];
> UINT8 revision [4];
> };
> R2DLL_API BOOL R2DLL_ReadFirmwareHeader (UINT16 port, struct IDSTRUCT* pStoreAdr);
>
> Is there a way to implement this with clusters in labVIEW?

Yep! Create a cluster with an UINT16, and three UINT32. Then you have
all the information. Typecast the UINT16 and the last UIN32 into a
string, and combine the middle two UINT32 into an array, and typecast
them into a string too.

Rolf

[mudder]

I'm not sure how to handle structs with unions with another struct inside.  I'm new at LabVIEW

what if the structure was like this:

#pragma pack(push, 2)

struct IDSTRUCT
{

   UINT32 temp;

   union

   {
      UINT32 x;

      struct

      {

         UINT32 x1    :1;

         UINT32 x2    :31;

      };
   };

   union

   {
      UINT32 y;

      struct

      {

         UINT32 y1    :1;

         UINT32 y2    :31;

      };
   };
};
#pragma pack(pop)

[Wiebe@CARYA]

"mudder" <x@no.email> wrote in message news:1171469412642-478205@exchange.ni.com...
I'm not sure how to handle structs with unions with another struct inside.&nbsp; I'm new at LabVIEW
&nbsp;
what if the structure was like this:
&nbsp;
#pragma pack(push, 2)
struct IDSTRUCT{
&nbsp;&nbsp; UINT32 temp;
&nbsp;&nbsp; union
&nbsp;&nbsp; {&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 x;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; struct
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 x1&nbsp;&nbsp;&nbsp; :1;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 x2 &nbsp;&nbsp; :31;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; };&nbsp;&nbsp; };
&nbsp;&nbsp;
&nbsp;&nbsp; union
&nbsp;&nbsp; {&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 y;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; struct
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 y1&nbsp;&nbsp;&nbsp; :1;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; UINT32 y2&nbsp;&nbsp;&nbsp; :31;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; };&nbsp;&nbsp; };};#pragma pack(pop)




This is basically a pointer to four U32's. Because it is a union, the pointer can point to:


temp { x {x1, x2 } }


Or:


temp { x {y1, y2 } }


I'd use a cluster with 4 U32's. The sub structures have no size, and can be ignored in LabVIEW.


Regards,


Wiebe.