How to read this structure with union from my Call Library Function Node?

[IAN CHUNG]

Trying to call the function below. I would like to read CL_MEASDATA information. Actually just need Evxy.

 

ER_CODE KMAPI CLGetMeasData(DEVICE_HANDLE hDevice, CL_COLORSPACE Type, CL_MEASDATA* pColor); 

typedef union tCL_MEASDATA

{

        CL_EvxyDATA           Evxy;                                       

        CL_EvuvDATA          Evuv;                                       

        CL_EvTduvDATA       EvTduv;                                   

        CL_EvDWPeDATA    EvDWPe;                                 

        CL_XYZDATA            XYZ;                                

        CL_RenderingDATA Rendering;                      

        CL_PWDATA            Pw;                                         

        CL_SPCDATA            Spc;                                 

}

CL_MEASDATA;

 

typedef struct tCL_EvxyDATA { float Ev; float x; float y; } CL_EvxyDATA;

 

typedef struct tCL_EvuvDATA { float Ev; float u; float v; } CL_EvuvDATA;

 

typedef struct tCL_EvTduvDATA { float Ev; float T; float duv; } CL_EvTduvDATA;

 

typedef struct tCL_EvDWPeDATA { float Ev; float DW; float Pe; } CL_EvDWPeDATA;

 

typedef struct tCL_XYZDATA { float X; float Y; float Z; } CL_XYZDATA;

 

typedef struct tCL_RenderingDATA { float Data[CL_RENDERING_LEN]; } CL_RenderingDATA;

The RenderingDATAis stored in the array in below order 0 1 2 ・・・ 14 15 Ra R1 R2 ・・・ R14 R15

 

typedef struct tCL_PWDATA { float PeakWave; } CL_PWDATA;

 

typedef struct tCL_ScotopicDATA { float Ev; float Es; float SP; } CL_ScotopicDATA;

 

[JKSH]

2 hours ago, IAN CHUNG said:

Trying to call the function below...

ER_CODE KMAPI CLGetMeasData(DEVICE_HANDLE hDevice, CL_COLORSPACE Type, CL_MEASDATA* pColor);

So here are more details about the other parts of the function: https://stackoverflow.com/questions/38632316/typeloadexception-using-dllimport

• ER_CODE: I32
• KMAPI: stdcall
• DEVICE_HANDLE: Pointer
• CL_COLORSPACE: Enum (size is not well-defined in C, but it's usually 32-bit)

 

Your CLFN must have Calling Convention = "stdcall (WINAPI)" and have 4 parameters:

Name	Type	Data Type/Format
return type	Numeric	Signed 32-bit Integer
hDevice	Numeric	Signed/Unsigned Pointer-sized Integer (pass by Value)
Type	Numeric	Signed/Unsigned 32-bit Integer (pass by Value)
pColor	Adapt to Type	Handles by Value

 

2 hours ago, IAN CHUNG said:

Actually just need Evxy.

...

typedef union tCL_MEASDATA

{

        CL_EvxyDATA           Evxy;                                       

        // ...                           

}

CL_MEASDATA;

 

typedef struct tCL_EvxyDATA { float Ev; float x; float y; } CL_EvxyDATA;

If you only want to read Evxy from the function, you can pretend that the parameter type is CL_EvxyDATA* instead of CL_MEASDATA*. This works because is a CL_MEASDATA union and CL_EvxyDATA is one of the structs it can store.

Make a Type Definition: A Cluster that contains 3 SGL numbers, and use this cluster to to tell the CLFN how to interpret the data.

Edited July 18, 2019 by JKSH
Add snippet

[IAN CHUNG]

Thank you very much for this kind reply.

I  tried this method (A Cluster that contains 3 SGL numbers, and use this cluster to to tell the CLFN how to interpret the data.).But it will show this error or the program crashed.

 

[IAN CHUNG]

This is the program. It can run to CL polling measure.vi

 

 libclapi.dlCL-500A.llb

[JKSH]

1 hour ago, IAN CHUNG said:

But it will show this error or the program crashed.

Oops, sorry... I didn't notice CL_RenderingDATA. This means the union is 64 bytes long.

Try using a cluster of 16 SGLs, and only read the first 3 values.

Or, try changing the parameter configuration:

• Type: Array
• Data type: 4-byte Single
• Dimensions: 1
• Array format: Array Data Pointer
• Minimum Size: 16

[IAN CHUNG]

Thank you very much! It works for  Array Data Pointer!

I used float array (Size: 16) and read  the first 3 values.

Thanks a lot!

 

 

[xufeng.ke]

Could you help to share your latest labview driver of CL-500A? thank you very much