[netcdfgroup] Problem with default fill values


I'm using libnetcdf_c++ v 6.2.

I have a variable where I wish to set my empty scalar float array to [0], but all I get is [_].

The ncdump result looks like this:

my_var =
 _ ;

But I want it to be:

my_var =
 0 ;

I have not altered the default fill.

Can anybody give me a hint about how I can du this?