#include <kern/locks.h>
Kernel (KEXT) › kern/ primitives

kern/locks.h Kernel.framework

includes: sys/cdefs.h, sys/appleapiopts.h, Kernel/mach/boolean.h, machine/locks.h, kern/assert.h, kern/kern_types.h, kern/lock_attr.h, kern/lock_group.h, kern/lock_mtx.h, kern/lock_rw.h, kern/lock_types.h
10 functions · 5 macros

macrodecl_lck_spin_data

#define decl_lck_spin_data(class, name) class lck_spin_t name

functionlck_spin_alloc_init

extern lck_spin_t *lck_spin_alloc_init(lck_grp_t *grp, lck_attr_t *attr)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Allocates a spin lock and initializes it in the manner of lck_spin_init with the given group and attributes. The result is freed with lck_spin_free.

functionlck_spin_init

extern void lck_spin_init(lck_spin_t *lck, lck_grp_t *grp, lck_attr_t *attr)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Initializes a spin lock, associating it with the given lock group (attributes are currently unused). Spin locks busy-wait with preemption disabled and are suitable for short critical sections, including ones taken from interrupt context; depending on platform configuration they are implemented as ticket locks.

functionlck_spin_lock

extern void lck_spin_lock(lck_spin_t *lck)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Locks the spin lock, disabling preemption and busy-waiting until it is available. Recursive acquisition by the holder is a deadlock; timeouts on the underlying hardware lock panic on time-limit exceeded.

functionlck_spin_lock_grp

extern void lck_spin_lock_grp(lck_spin_t *lck, lck_grp_t *grp)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
As lck_spin_lock, but attributes the acquisition (for lock statistics) to the given lock group. Functionally identical to lck_spin_lock when statistics are not enabled.

functionlck_spin_unlock

extern void lck_spin_unlock(lck_spin_t *lck)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Unlocks the spin lock and re-enables preemption.

functionlck_spin_destroy

extern void lck_spin_destroy(lck_spin_t *lck, lck_grp_t *grp)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Destroys a spin lock initialized with lck_spin_init, marking it unusable and dropping its reference on the lock group. Does not free the memory; for locks obtained from lck_spin_alloc_init use lck_spin_free.

functionlck_spin_free

extern void lck_spin_free(lck_spin_t *lck, lck_grp_t *grp)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/locks_arm.c
Destroys a spin lock allocated by lck_spin_alloc_init and frees its memory.

functionlck_spin_sleep

extern wait_result_t lck_spin_sleep(
	lck_spin_t *lck,
	lck_sleep_action_t lck_sleep_action,
	event_t event,
	wait_interrupt_t interruptible
)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/kern/locks.c
Atomically releases the spin lock and waits for the specified event; on wakeup the lock is re-acquired unless LCK_SLEEP_UNLOCK is set in lck_sleep_action. Returns the wait result per the interruptible argument (THREAD_AWAKENED, THREAD_INTERRUPTED, ...). Panics on invalid action bits. Spin-mode-only actions such as LCK_SLEEP_SPIN do not apply.

functionlck_spin_sleep_grp

extern wait_result_t lck_spin_sleep_grp(
	lck_spin_t *lck,
	lck_sleep_action_t lck_sleep_action,
	event_t event,
	wait_interrupt_t interruptible,
	lck_grp_t *grp
)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/kern/locks.c
As lck_spin_sleep, but attributes the re-acquisition of the lock to the given lock group for statistics purposes.

functionlck_spin_sleep_deadline

extern wait_result_t lck_spin_sleep_deadline(
	lck_spin_t *lck,
	lck_sleep_action_t lck_sleep_action,
	event_t event,
	wait_interrupt_t interruptible,
	uint64_t deadline
)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/kern/locks.c
As lck_spin_sleep, but the wait is bounded by an absolute deadline in mach_absolute_time units (via assert_wait_deadline); the wait result is THREAD_TIMED_OUT if the deadline expires before wakeup.

macroLCK_SPIN_ASSERT

#define LCK_SPIN_ASSERT(lck, type)

macroLCK_SPIN_ASSERT_DEBUG

#define LCK_SPIN_ASSERT_DEBUG(lck, type)

macroLCK_ASSERT_OWNED

#define LCK_ASSERT_OWNED 1

macroLCK_ASSERT_NOTOWNED

#define LCK_ASSERT_NOTOWNED 2