case *ast.SelectorExpr:
		goname = fun.Sel.Name
	case *ast.Ident:
		goname = strings.TrimPrefix(fun.Name, "_C2func_")
		goname = strings.TrimPrefix(goname, "_Cfunc_")
	}
	if goname == "" || goname == "malloc" {
		return "", false
	}
	name := f.Name[goname]
	if name == nil || name.Kind != "func" {
		// Probably a type conversion.
		return "", false
	}

	params := name.FuncType.Params