• 2021.4
  • 09/27/2021
  • Public Content
Contents

Reader Writer Mutexes

Mutual exclusion is necessary when at least one thread
writes
to a shared variable. But it does no harm to permit multiple readers into a protected region. The reader-writer variants of the mutexes, denoted by
_rw_
in the class names, enable multiple readers by distinguishing
reader locks
from
writer locks.
There can be more than one reader lock on a given mutex.
Requests for a reader lock are distinguished from requests for a writer lock via an extra boolean parameter in the constructor for
scoped_lock
. The parameter is false to request a reader lock and true to request a writer lock. It defaults to
true
so that when omitted, a
spin_rw_mutex
or
queuing_rw_mutex
behaves like its non-
_rw_
counterpart.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.