FltAcquirePushLockSharedEx function (fltkernel.h)
The FltAcquirePushLockSharedEx routine acquires the given push lock for shared access by the calling thread.
Syntax
VOID FLTAPI FltAcquirePushLockSharedEx(
PEX_PUSH_LOCK PushLock,
ULONG Flags
);
Parameters
PushLock
Opaque push lock pointer. This pointer must have been initialized by a previous call to FltInitializePushLock.
Flags
A bitmask of flags that control the attributes of the lock.
Return value
None.
Remarks
The FltAcquirePushLockSharedEx routine acquires the given push lock for shared access by the calling thread.
Push locks are similar to ERESOURCE structures (also called resources) in that they can be acquired for shared or exclusive access. For more information about push locks, see the reference entry for FltInitializePushLock.
Unlike ERESOURCE structures, push locks cannot be acquired recursively. If the caller already has acquired the push lock for exclusive access, the system will hang. If the caller already has acquired the push lock for shared access, it can receive shared access again. However, each call to FltAcquirePushLockShared must be matched by a subsequent call to FltReleasePushLock.
When the caller will be given shared access to the given push lock depends on the following:
If the push lock is currently unowned, shared access is granted immediately to the current thread.
If the push lock has already been acquired for shared access by another thread and no thread is waiting for exclusive access to the push lock, shared access is granted to the caller immediately. The caller is put into a wait state if there is an exclusive waiter.
If the push lock has already been acquired for exclusive access by another thread or if there is another thread waiting for exclusive access, the current thread is put into a wait state until the push lock can be acquired.
Requirements
| Requirement | Value |
|---|---|
| Header | fltkernel.h |
| Library | FltMgr.lib |