C++ 多层SRWLock有效吗?
例如,此代码有效吗C++ 多层SRWLock有效吗?,c++,winapi,C++,Winapi,例如,此代码有效吗 SRWLOCK srwLockA; SRWLOCK srwLockB; ::InitializeSRWLock( &srwLockA); ::InitializeSRWLock( &srwLockB); ::AcquireSRWLockExclusive( &srwLockA ); // First level /* do some stuff with member A*/ ::AcquireSRWLockExclusive( &a
SRWLOCK srwLockA;
SRWLOCK srwLockB;
::InitializeSRWLock( &srwLockA);
::InitializeSRWLock( &srwLockB);
::AcquireSRWLockExclusive( &srwLockA ); // First level
/* do some stuff with member A*/
::AcquireSRWLockExclusive( &srwLockB ); // Second level
/* do some stuff with member A & B */
::ReleaseSRWLockExclusive( &srwLockB ); // Second level
/* do some stuff with member A**/
::ReleaseSRWLockExclusive( &srwLockA ); // First level
srwLockA和srwLockB旨在分别保护成员A和成员B。
我只是想知道SRWlock是否可以用这种方法。这应该行得通
“递归获取锁”指两次获取同一个锁。例如:
SRWLOCK lock;
::InitializeSRWLock( &lock );
::AcquireSRWLockExclusive( &lock ); // acquire the lock
// Now we have the lock
::AcquireSRWLockExclusive( &lock ); // acquire the lock again!?
// Now we still have the lock
::ReleaseSRWLockExclusive( &lock ); // release the lock
// Now we STILL have the lock?
::ReleaseSRWLockExclusive( &lock ); // release the lock again
// Now we don't.
这不适用于SRW锁。它确实适用于某些类型的锁,例如互斥锁(当然,对于互斥锁,您可以使用WaitForSingleObject
和releasemotex
而不是AcquireSRWLockExclusive
和ReleaseSRWLockExclusive
)
您可以获取多个不相关的锁,因为它们彼此都不了解。FWIW,我对它的理解(在测试之前不能保证100%正确):
- 可以在同一线程中获取SRWLock,同时已经在同一线程中获取另一个SRWLock
- 无法在同一线程中重新获取SRWLock,而在同一线程中已经获取了相同的SRWLock;最有可能的是,这种递归获取相同锁的尝试将导致无限的自死锁(类似于*nix中的非递归互斥)