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IoGetTopLevelIrp function (ntifs.h)

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The IoGetTopLevelIrp routine returns the value of the TopLevelIrp field of the current thread.

Syntax

PIRP IoGetTopLevelIrp();

Return value

IoGetTopLevelIrp returns the value of the TopLevelIrp field of the current thread.

Remarks

IoGetTopLevelIrp can return NULL, an arbitrary file-system-specific value (such as a pointer to the current IRP), or one of the flags listed in the following table.

If the current thread holds no resources above the file system, IoGetTopLevelIrp returns NULL.

If the file system is the top-level component for the current thread, IoGetTopLevelIrp returns a pointer to the current IRP.

If a component other than the file system is the top-level component for the current thread, IoGetTopLevelIrp returns one of the following flags:

Flag Meaning
FSRTL_FSP_TOP_LEVEL_IRP This is a recursive call.
FSRTL_CACHE_TOP_LEVEL_IRP The cache manager is the top-level component for the current thread.
FSRTL_MOD_WRITE_TOP_LEVEL_IRP The modified page writer is the top-level component for the current thread.
FSRTL_FAST_IO_TOP_LEVEL_IRP The cache manager is the top-level component for the current thread, and the current thread is in a fast I/O path.

Requirements

Requirement Value
Target Platform Universal
Header ntifs.h (include Ntifs.h, Wdm.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL <= DISPATCH_LEVEL

See also

IoSetTopLevelIrp