How to pass union of structure array to a function?

[Alex]

How to pass union of structure to a function?
Say I have got a :

struct FrameStr
{
BYTE length ;
BYTE ID ;
BYTE command ;
BYTE DataByte ;
BYTE CRC ;
};

union FrameType
{
BYTE FrameArr[5];
struct FrameStr Frame;
}
FrameTx;

And I want to pass it to a function GenerateCRC:
GenerateCRC(FrameTx.FrameArr);

So, in the function:
BYTE GenerateCRC(union FrameType *msg)
or
BYTE GenerateCRC(union FrameType msg[])

I guess msg should have the address of the array. But it does not

[Mark]