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REQUEST_OPLOCK_INPUT_BUFFER structure (winioctl.h)

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Contains the information to request an opportunistic lock (oplock) or to acknowledge an oplock break with the FSCTL_REQUEST_OPLOCK control code.

Syntax

typedef struct _REQUEST_OPLOCK_INPUT_BUFFER {
  WORD  StructureVersion;
  WORD  StructureLength;
  DWORD RequestedOplockLevel;
  DWORD Flags;
} REQUEST_OPLOCK_INPUT_BUFFER, *PREQUEST_OPLOCK_INPUT_BUFFER;

Members

StructureVersion

The version of the REQUEST_OPLOCK_INPUT_BUFFER structure that is being used. Set this member to REQUEST_OPLOCK_CURRENT_VERSION.

StructureLength

The length of this structure, in bytes. Must be set to sizeof(REQUEST_OPLOCK_INPUT_BUFFER).

RequestedOplockLevel

A valid combination of the following oplock level values.

Value Meaning
OPLOCK_LEVEL_CACHE_READ
 Allows clients to cache reads. May be granted to multiple clients.
OPLOCK_LEVEL_CACHE_HANDLE
 Allows clients to cache open handles. May be granted to multiple clients.
OPLOCK_LEVEL_CACHE_WRITE
 Allows clients to cache writes and byte range locks. May be granted only to a single client.
 

Valid combinations of these values are as follows:

  • OPLOCK_LEVEL_CACHE_READ
  • OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_HANDLE
  • OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_WRITE
  • OPLOCK_LEVEL_CACHE_READ | OPLOCK_LEVEL_CACHE_WRITE | OPLOCK_LEVEL_CACHE_HANDLE
For more information about these value combinations, see FSCTL_REQUEST_OPLOCK.

Flags

A valid combination of the following request flag values.

Value Meaning
REQUEST_OPLOCK_INPUT_FLAG_REQUEST
 Request for a new oplock. Setting this flag together with REQUEST_OPLOCK_INPUT_FLAG_ACK is not valid and will cause the request to fail with ERROR_INVALID_PARAMETER.
REQUEST_OPLOCK_INPUT_FLAG_ACK
 Acknowledgment of an oplock break. Setting this flag together with REQUEST_OPLOCK_ INPUT_FLAG_REQUEST is not valid and will cause the request to fail with ERROR_INVALID_PARAMETER.

Requirements

Requirement Value
Minimum supported client Windows 7 [desktop apps only]
Minimum supported server Windows Server 2008 R2 [desktop apps only]
Header winioctl.h (include Windows.h)

See also

FSCTL_REQUEST_OPLOCK

REQUEST_OPLOCK_OUTPUT_BUFFER