NAME    [Toc]    [Back]

       lock_write - Asserts a complex lock with write access

SYNOPSIS    [Toc]    [Back]

       #include <kern/lock.h>

       void lock_write(
               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 assert a complex lock with write 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_write routine asserts a lock with exclusive write
       access for the resource associated with the specified lock
       structure  pointer.  This  means that once a write lock is
       asserted, no other kernel thread can gain  read  or  write
       access to the resource until it is released.

       To  release  a complex write lock successfully asserted by
       lock_write, call the lock_done routine.

NOTES    [Toc]    [Back]

       You must call  lock_init  (once  only)  prior  to  calling
       lock_write  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]

       None

FILES    [Toc]    [Back]

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

       Data Structures: lock(9s)



                                                   lock_write(9r)