cu/bistptr.h: Bi-Strength Pointer
[Utilities]

Data Structures
struct	cu_bistptr_t
Functions
cu_bool_t	cu_bistptr_is_weak (cu_bistptr_t *bsp)
cu_bool_t	cu_bistptr_is_strong (cu_bistptr_t *bsp)
void *	cu_bistptr_get_weak (cu_bistptr_t *bsp)
void *	cu_bistptr_get_strong (cu_bistptr_t *bsp)
void *	cu_bistptr_get (cu_bistptr_t *bsp)
void	cu_bistptr_init_weak (cu_bistptr_t *bsp, void *obj)
void	cu_bistptr_init_strong (cu_bistptr_t *bsp, void *obj)
void	cu_bistptr_deinit (cu_bistptr_t *bsp)
void	cu_bistptr_assign_weak (cu_bistptr_t *bsp, void *obj)
void	cu_bistptr_assign_strong (cu_bistptr_t *bsp, void *obj)

---

Detailed Description

This header implements a discriminated union of a strong and a weak pointer, but with the restriction that all pointers stored must be even, e.g. due to alignment.

See also:

cu/weakptr.h: Weak Pointers "cu/weakptr.h"

---

Function Documentation

void cu_bistptr_assign_strong	(	cu_bistptr_t *	bsp,
		void *	obj
	)

Reinitialise bsp to hold a strong pointer to obj.

Precondition:

obj is aligned to an even address.

void cu_bistptr_assign_weak	(	cu_bistptr_t *	bsp,
		void *	obj
	)

Reinitialise bsp to hold a weak pointer to obj.

Precondition:

obj is aligned to an even address and points to or inside collectable memory.

void cu_bistptr_deinit

(

cu_bistptr_t *

bsp

)

Deininialise bsp. If bsp holds a weak pointer, this unregisters the corresponding disappearing link.

void* cu_bistptr_get

(

cu_bistptr_t *

bsp

)

Returns the pointer stored in bsp, independent of strength.

void* cu_bistptr_get_strong

(

cu_bistptr_t *

bsp

)

Returns the strong pointer of bsp.

Precondition:

cu_bistptr_is_strong(ptr)

void* cu_bistptr_get_weak

(

cu_bistptr_t *

bsp

)

Returns the weak pointer held by bsp.

Precondition:

cu_bistptr_is_weak(ptr)

void cu_bistptr_init_strong	(	cu_bistptr_t *	bsp,
		void *	obj
	)

Initialise bsp to a strong pointer to obj.

Precondition:

obj is aligned to an even address.

void cu_bistptr_init_weak	(	cu_bistptr_t *	bsp,
		void *	obj
	)

Initialise bsp to a weak pointer to obj.

Precondition:

obj is aligned to an even address and points to or inside collectable memory.

cu_bool_t cu_bistptr_is_strong

(

cu_bistptr_t *

bsp

)

The complement of cu_bistptr_is_weak, for symmetry.

cu_bool_t cu_bistptr_is_weak

(

cu_bistptr_t *

bsp

)

True iff bsp is a weak pointer. The NULL pointer counts as strong.