Did you actually try this? If you try it, you'll get error messages which make it very clear. For example, when you try to pass a cellView id to hiGetCommandPoint, it says:
*Error* hiGetCommandPoint: argument #1 should be a window type (type template = "w") - db:202165292
If you read the manual for this function, that is also clear. So something like:
would do it. However, this would need to be triggered by a bindkey, because if you just type it in the CIW, the cursor would have left the window, and hence it will return nil.
The next problem is that you're trying to do use %d to print a list. %L would be better - %d will give an error because the return value of the function is not an integer.
So if you do:
printf("Point was %L\n" coord)
hiSetBindKey("Layout" "<Key>x" "MYgetPoint()")
It will work.
It may be your English, but people will be more willing to help if you appear to have tried to figure it out yourself, explaining what you tried, what the errors were and so on. As it is, your post looks more like "please do my work for me"...