+/* For lval_computed values, this structure holds functions used to
+ retrieve and set the value (or portions of the value).
+
+ For each function, 'V' is the 'this' pointer: an lval_funcs
+ function F may always assume that the V it receives is an
+ lval_computed value, and has F in the appropriate slot of its
+ lval_funcs structure. */
+
+struct lval_funcs
+{
+ /* Fill in VALUE's contents. This is used to "un-lazy" values. If
+ a problem arises in obtaining VALUE's bits, this function should
+ call 'error'. */
+ void (*read) (struct value *v);
+
+ /* Handle an assignment TOVAL = FROMVAL by writing the value of
+ FROMVAL to TOVAL's location. The contents of TOVAL have not yet
+ been updated. If a problem arises in doing so, this function
+ should call 'error'. */
+ void (*write) (struct value *toval, struct value *fromval);
+
+ /* Return a duplicate of VALUE's closure, for use in a new value.
+ This may simply return the same closure, if VALUE's is
+ reference-counted or statically allocated.
+
+ This may be NULL, in which case VALUE's closure is re-used in the
+ new value. */
+ void *(*copy_closure) (struct value *v);
+
+ /* Drop VALUE's reference to its closure. Maybe this frees the
+ closure; maybe this decrements a reference count; maybe the
+ closure is statically allocated and this does nothing.
+
+ This may be NULL, in which case no action is taken to free
+ VALUE's closure. */
+ void (*free_closure) (struct value *v);
+};
+
+/* Create a computed lvalue, with type TYPE, function pointers FUNCS,
+ and closure CLOSURE. */
+
+extern struct value *allocate_computed_value (struct type *type,
+ struct lval_funcs *funcs,
+ void *closure);
+
+/* If VALUE is lval_computed, return its lval_funcs structure. */
+
+extern struct lval_funcs *value_computed_funcs (struct value *value);
+
+/* If VALUE is lval_computed, return its closure. The meaning of the
+ returned value depends on the functions VALUE uses. */
+
+extern void *value_computed_closure (struct value *value);
+