NAME    [Toc]    [Back]

       lock_try_read  -  General:  Tries to assert a complex lock
       with read-only access

SYNOPSIS    [Toc]    [Back]

       #include <kern/lock.h>

       boolean_t lock_try_read(
               lock_t lock_structptr );

ARGUMENTS    [Toc]    [Back]

       Specifies a pointer to the complex lock  structure,  lock.
       This is the lock structure associated with the resource on
       which you want to try to assert a complex lock with  readonly
  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    [Toc]    [Back]

       The lock_try_read routine tries to assert a  complex  lock
       (without  blocking) with read-only access for the resource
       associated with the specified lock structure  pointer.  To
       release  a complex lock with read-only access successfully
       asserted by lock_try_read, call the lock_done routine.

NOTES    [Toc]    [Back]

       You must call  lock_init  (once  only)  prior  to  calling
       lock_try_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    [Toc]    [Back]

       The  lock_try_read  routine  returns  one of the following
       values: The attempt to acquire the read-only complex  lock
       was successful.  The attempt to acquire the read-only complex
 lock was unsuccessful.

FILES    [Toc]    [Back]

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

       Data Structures: lock(9s)



                                                lock_try_read(9r)