Microsoft Windows CE 3.0  


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This function acquires a spin lock so that the caller can synchronize access to resources shared among driver functions not related to interrupts.

VOID NdisDprAcquireSpinLock(


Pointer to an opaque spin lock, already initialized by the caller.


In Windows CE, NDIS spinlocks are implemented using critical sections.

The NIC driver must initialize a variable of type NDIS_SPIN_LOCK with the NdisAllocateSpinLockfunction before it calls any other Ndis XXX SpinLockfunction. The driver must provide resident storage for the spin lock(s) it uses.

This function is an optimized version of NdisAcquireSpinLockthat a miniport can call only while running at IRQL DISPATCH_LEVEL.

After acquiring a spin lock with this function, the caller must release that lock with a call to the NdisDprReleaseSpinLockfunction. An NIC driver must call NdisDprReleaseSpinLockfollowing each call to this function. Otherwise, a deadlock occurs, hanging the driver.

A spin lock acquired with this function must be released with NdisDprReleaseSpinLock. A spin lock acquired with NdisAcquireSpinLockmust be released with NdisReleaseSpinLock.

A driver should never hold a spin lock for an extended period — more than a few instructions. Holding a spin lock for longer than 25 microseconds degrades both system and driver performance.

A miniport driver cannot use a spin lock to protect resources that its other functions share with the MiniportISRand/or MiniportDisableInterruptfunctions. Instead, a miniport must call the NdisMSynchronizeWithInterruptfunction so that its MiniportSynchronizeISRfunction accesses such shared resources at the same DIRQL at which its MiniportISRand/or MiniportDisableInterruptfunctions do.

A driver that calls this function must be running at IRQL DISPATCH_LEVEL.


Runs on Versions Defined in Include Link to
Windows CE OS 2.0 and later Ndis.h    
Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

NdisAcquireSpinLock, NdisDprReleaseSpinLock, NdisMSynchronizeWithInterrupt

 Last updated on Tuesday, July 13, 2004

© 2004 Microsoft Corporation. All rights reserved.