FltAcquirePushLockExclusive function (fltkernel.h)

The FltAcquirePushLockExclusive macro acquires the given push lock for exclusive access by the calling thread.

Syntax

VOID FLTAPI FltAcquirePushLockExclusive(
  [in, out] PEX_PUSH_LOCK PushLock
);

Parameters

[in, out] PushLock

Opaque push lock pointer of type PEX_PUSH_LOCK. This pointer must have been initialized by a previous call to FltInitializePushLock.

Return value

None.

Remarks

FltAcquirePushLockExclusive acquires the given push lock for exclusive 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 or shared access, the thread will hang.

When the caller will be given exclusive access to the given push lock depends on the following:

• If the push lock is currently unowned, exclusive access is granted immediately to the current thread.

• If the push lock has already been acquired for exclusive or shared access by another thread, the current thread is put into a wait state until the push lock can be acquired.

Because FltAcquirePushLockExclusive disables normal kernel APC delivery, it is not necessary to call KeEnterCriticalRegion or FsRtlEnterFileSystem before calling FltAcquirePushLockExclusive.

To release the push lock after it is acquired, call FltReleasePushLock. Every call to FltAcquirePushLockExclusive must be matched by a subsequent call to FltReleasePushLock.

To acquire a push lock for shared access, call FltAcquirePushLockShared.

To initialize a push lock, call FltInitializePushLock.

To delete a push lock, call FltDeletePushLock.

Requirements

See also

FltAcquirePushLockExclusiveEx

FltAcquirePushLockShared

FltDeletePushLock

FltInitializePushLock

FltReleasePushLock

FsRtlEnterFileSystem

KeEnterCriticalRegion