struct doesnt compile

[joem]

Hello All,

Porting some come from  MS VC++ 6.0 to Labwindow/CVI 5.0 under XP

Labwindows can not compile the struct below. I get the error "Field name missing"

with the cursor located on the semi colon after the unions close brace.

If I put a name in after the close brace it will compile but then I have other problems.

I compiled this struct  using another ansi c compilier with out problems. 

/---------------code-----------------/

typedef struct  _GENPORT_WRITE_INPUT {
    ULONG   PortNumber;  // Port # to write to
    union  {               // Data to be output to port
        ULONG   LongData;
        USHORT  ShortData;
        UCHAR   CharData;
    };   
}   GENPORT_WRITE_INPUT;

/--------------end code ------------/

Thanks in advance

Joe

[jr_2005]

Surely the union must have a name; otherwise how can you refer to its elements later?

JR

[joem]

I refer to the element like this.

This works, i tested it in VC++

/------------------------------------------------------/  

  GENPORT_WRITE_INPUT InputBuffer;
   unsigned short dataValue=10;

   InputBuffer.ShortData = dataValue;

  printf(%i,InputBuffer.ShortData);

/-------------------------------------------------------/

[jr_2005]

How 'bout that! It compiles just fine on my CVI 7.0! All these years I've been doing it the long way... You learn something new every day

JR

[Mert_A.]

Hello,

Allowing unnamed struct/union fields within an enclosing struct/union is an extension to the C language supported by some compiler vendors, including Microsoft (refer to the Microsoft Specific section on this page).  I don't believe that LabWindows/CVI 5.0 supports this extension, though later versions do.  In order to get your struct to compile in CVI, it looks like you will have to give the field a name.

Hope this helps.

Mert A.
National Instruments

Message Edited by Mert A. on 08-18-2006 10:16 AM

[joem]

Or upgrade : )