lock_read - General: Asserts a complex lock with read-only
lock_t lock_structptr );
Specifies a pointer to the complex lock structure, lock.
This is the lock structure associated with the resource on
which you want to assert a complex lock with read-only
access. The lock structure is an opaque data structure;
that is, its associated members are referenced and manipulated
by the operating system and not by the user of the
complex lock mechanism.
The lock_read routine asserts a lock with read-only access
for the resource associated with the specified lock structure
pointer. The lock_read routine allows multiple kernel
threads to access the resource read-only at the same time.
When a read lock is asserted, the protected resource is
guaranteed not to change.
To release a previously asserted read lock, call the
You must call lock_init (once only) prior to calling
lock_read to initialize the lock structure pointer for the
resource. A resource, from the kernel module's standpoint,
is data that more than one kernel thread can manipulate.
You can store the resource in global variables and
in data structure members.
Routines: lock_done(9r), lock_terminate(9r),
lock_try_read(9r), lock_try_write(9r), lock_write(9r)
Data Structures: lock(9s)
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