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lock_read(9r)
NAME
  lock_read - General: Asserts a complex lock with read-only access

SYNOPSIS
  #include <kern/lock.h>

  void lock_read(
	  lock_t lock_structptr );

ARGUMENTS
  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.

DESCRIPTION
  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 lock_done routine.

NOTES
  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.

RETURN VALUES
  None

FILES
  <lock.h>

SEE ALSO
  Routines: lock_done(9r), lock_terminate(9r), lock_try_read(9r),
  lock_try_write(9r), lock_write(9r)

  Data Structures: lock(9s)

Index for Section 9r

Alphabetical listing for L

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