Ref3 method

P Ref3([
  1. X? o
])

Allocates o into slot '3', or reuses the existing slot '3' allocation if o is null.

Intended as a short-lived scratch reference within a single C call. Use RefUpdate3 if the callee may write back into the pointer.

Implementation

P Ref3([X? o]) => _Ref(o, '3');