IoIsOperationSynchronous function (ntifs.h)

Article
09/28/2023

The IoIsOperationSynchronous routine determines whether a given IRP represents a synchronous or asynchronous I/O request.

Syntax

BOOLEAN IoIsOperationSynchronous(
  [in] PIRP Irp
);

Parameters

[in] Irp

Pointer to the IRP for the operation.

Return value

IoIsOperationSynchronous returns TRUE if the operation is synchronous, otherwise FALSE.

Remarks

IoIsOperationSynchronous determines whether a given IRP requests a synchronous or asynchronous I/O operation, according to the following conditions:

If the IRP requests asynchronous paging I/O, the operation is asynchronous, even if one of the other conditions is true.
If the IRP requests synchronous paging I/O, the operation is synchronous.
If the file object was opened for synchronous I/O, the operation is synchronous.
If the IRP_SYNCHRONOUS_API flag is set in the IRP, the operation is synchronous. This flag is set for operations, such as ZwQueryInformationFile and ZwSetInformationFile, that are always synchronous, even when performed on a file object that was opened for asynchronous I/O.
If none of the above conditions is true, the operation is asynchronous.

IoIsOperationSynchronous also returns TRUE if the IRP contains an IOCTL or FSCTL request with an I/O or file system control code 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.

Requirements

Requirement	Value
Target Platform	Universal
Header	ntifs.h (include Ntifs.h)
Library	NtosKrnl.lib
DLL	NtosKrnl.exe
IRQL	Any level