Function fill_action:
Defined in module fluid (file: /std/fluid.c)

fill_action(container)
This function is called by the container
in the fluid just before it fills the container.
The container passes itself as an argument.
This function must return a 1 for the filling
to continue.  This gives the fluid itself
an opportunity to halt the filling action.

Prototype:
int fill_action( object vessel );
