SVR5
RW_UNLOCK(D3)
RW_UNLOCK --
release a read/write lock
Synopsis
#include <sys/types.h>
#include <sys/ksynch.h>
#include <sys/ddi.h>
void RW_UNLOCK(rwlock_t *lockp, pl_t pl);
Description
The RW_UNLOCK function
releases the read/write lock specified by lockp and then
sets the interrupt priority level in accordance with the value
specified by pl (if required by the implementation).
If the lock is held in read mode by multiple contexts,
RW_UNLOCK releases the lock in the calling context
but does not cause the lock to be released in any other context.
Arguments
lockp-
Pointer to the read/write lock to be released.
pl-
The interrupt priority level to be set after releasing the lock.
Return values
None
Usage
See the description of the min_pl argument to
RW_ALLOC(D3)
for a list of the valid values for pl.
If lock calls are not being nested or if the caller is unlocking in the
reverse order that locks were acquired, the pl argument will typically
be the value that was returned from the corresponding call to acquire the lock.
The caller may need to specify a different value for pl if nested locks
are released in some order other than the reverse order of acquisition, so as
to ensure that the interrupt priority level is kept sufficiently high to
block interrupt code that might attempt to acquire locks which are still held.
Although portable drivers must always specify an appropriate pl argument,
implementations which do not require that the interrupt priority level be
raised during lock acquisition may choose to ignore this argument.
Context and synchronization
Non-blockable, interrupt, user, or blockable
context.
Hardware applicability
All
Version applicability
ddi:
5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp
References
RW_ALLOC(D3),
RW_DEALLOC(D3),
RW_RDLOCK(D3),
RW_TRYRDLOCK(D3),
RW_TRYWRLOCK(D3),
RW_WRLOCK(D3)
``Spin locks (DDI)'' in HDK Technical Reference
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 6 and UnixWare (SVR5) HDK - June 2005