FltIsOperationSynchronous - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
// fltkernel.h

BOOLEAN FLTAPI FltIsOperationSynchronous(
  [in] PFLT_CALLBACK_DATA CallbackData
);

View the official Windows Driver Kit DDI reference

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Windows Driver Kit DDI reference (nf-fltkernel-fltisoperationsynchronous)

FltIsOperationSynchronous function

Description

The FltIsOperationSynchronous routine determines whether a given callback data structure (FLT_CALLBACK_DATA) represents a synchronous or asynchronous I/O operation.

Parameters

CallbackData [in]

Pointer to the callback data structure for the operation (FLT_CALLBACK_DATA).

Return value

FltIsOperationSynchronous returns TRUE if the operation is synchronous, and FALSE if the operation is asynchronous.

Remarks

FltIsOperationSynchronous determines whether a given callback data structure (FLT_CALLBACK_DATA) represents a synchronous or asynchronous I/O operation, according to the following conditions:

[!NOTE]

FltIsOperationSynchronous also returns TRUE if the callback data structure represents an IRP_MJ_DEVICE_CONTROL, IRP_MJ_INTERNAL_DEVICE_CONTROL, or IRP_MJ_FILE_SYSTEM_CONTROL operation with an I/O control code (IOCTL) or file system control code (FSCTL) that was defined with METHOD_BUFFERED, even if the file object was opened for asynchronous I/O. Such a request is likely to be made synchronous by the file system, but this is not necessarily true in all cases.

When FltIsOperationSynchronous returns TRUE, this does not indicate that the I/O operation is synchronized. That is, the TRUE value does not indicate that a minifilter driver returned FLT_PREOP_SYNCHRONIZE in the preoperation callback (PFLT_POST_OPERATION_CALLBACK) routine for this operation. Instead, FltIsOperationSynchronous returns TRUE to indicate that the I/O operation is synchronous from the I/O manager's perspective.

FltIsOperationSynchronous can be called for all classes of operations: fast I/O, file system filter (FSFilter) callbacks, and IRP-based operations.

See also

FLT_CALLBACK_DATA

FLT_IS_FASTIO_OPERATION

FLT_IS_FS_FILTER_OPERATION

FLT_IS_IRP_OPERATION

IoIsOperationSynchronous