Data Structures |
class | gaurd_reader |
| Gaurd class to apply scope based access locking to objects. More...
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class | gaurd_writer |
| Gaurd class to apply scope based exclusive locking to objects. More...
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Public Member Functions |
bool | access (timeout_t timeout=Timer::inf) |
| Request shared (read) access through the lock.
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unsigned | getAccess (void) |
| Get the number of threads in shared access mode.
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unsigned | getModify (void) |
| Get the number of threads waiting to modify the lock.
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unsigned | getWaiting (void) |
| Get the number of threads waiting to access after writer completes.
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bool | modify (timeout_t timeout=Timer::inf) |
| Request modify (write) access through the lock.
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void | release (void) |
| Release the lock.
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| ThreadLock () |
| Create an instance of a rwlock.
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Static Public Member Functions |
static bool | access (ThreadLock &lock, timeout_t timeout=Timer::inf) |
| Convenience function to access (read lock) a rwlock.
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static void | indexing (unsigned size) |
| Specify hash table size for gaurd protection.
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static bool | modify (ThreadLock &lock, timeout_t timeout=Timer::inf) |
| Convenience function to modify (write lock) a rwlock.
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static bool | reader (void *object, timeout_t timeout=Timer::inf) |
| Shared access to an arbitrary object.
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static void | release (void *object) |
| Release an arbitrary object that has been protected by a rwlock.
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static void | release (ThreadLock &lock) |
| Convenience function to release a rwlock.
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static bool | writer (void *object, timeout_t timeout=Timer::inf) |
| Write protect access to an arbitrary object.
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Protected Member Functions |
void | Exlock (void) |
| Protocol interface to exclusive lock the object.
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void | Shlock (void) |
| Protocol interface to share lock the object.
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void | Unlock (void) |
| Protocol interface to release a lock.
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Protected Attributes |
pthread_t | writeid |
unsigned | writers |
A generic and portable implimentation of Read/Write locking.
This class impliments classical read/write locking, including "timed" locks. Support for scheduling threads to avoid writer starvation is also provided for. By building read/write locks from a conditional, we make them available on pthread implimetations and other platforms which do not normally include optional pthread rwlock's. We also do not restrict the number of threads that may use the lock. Finally, both the exclusive and shared protocols are implimented to support exclusive_lock and shared_lock referencing.
- Author:
- David Sugar <dyfet@gnutelephony.org>