Callback Parameters

Applies to: Windows | Windows Server

Callback Parameters

This topic contains parameters that are used for callbacks.

JET_paramDisableCallbacks
65

This parameter disables all database engine callbacks to application provided functions. It is primarily intended to support the database engine utilities and is not intended to be used in your application.

Label Value

Default Value:

False

Type:

Boolean

Valid Range:

False, True

Scope:

Instance

Set After JetCreateInstance:

Yes

Set after JetInit:

No

Affects Physical Layout:

No

Affects Reliability:

No

Affects Performance:

No

Affects Resources:

No

Availability:

Windows XP and later releases

JET_paramEnablePersistedCallbacks
156

This parameter enables the use of persistent callbacks in the database. In releases prior to Windows Vista, the use of persistent callbacks was enabled by default. Applications must now explicitly enable the use of persistent callbacks at runtime using this parameter. If this parameter is not set, then any database operation that requires the invocation of a callback will fail with JET_errCallbackFailed. This parameter does not affect any callbacks that are specified at runtime with the following mechanisms: JET_paramRuntimeCallback, JetRegisterCallback, or an explicit callback parameter to a JET API. It is still possible to create schema elements that contain persistent callbacks even when the use of those persistent callbacks is disallowed. When this parameter is set to false it overrides JET_paramDisableCallbacks.

Label Value

Default Value:

False

Type:

Boolean

Valid Range:

False, True

Scope:

Instance

Set After JetCreateInstance:

Yes

Set after JetInit:

No

Affects Physical Layout:

No

Affects Reliability:

No

Affects Performance:

No

Affects Resources:

No

Availability:

Windows Vista and later releases

JET_paramRuntimeCallback
73

This parameter configures the engine with a runtime callback function implementing the JET_CALLBACK interface. This callback may be called for the following reasons: JET_cbtypFreeCursorLS, JET_cbtypFreeTableLS, or JET_cbtypNull. Please see JetSetLS for more information.

Label Value

Default Value:

NULL

Type:

Function Pointer (JET_API_PTR)

Valid Range:

NULL, JET_CALLBACK*

Scope:

Instance

Set After JetCreateInstance:

Yes

Set after JetInit:

No

Affects Physical Layout:

No

Affects Reliability:

No

Affects Performance:

No

Affects Resources:

No

Availability:

Windows XP and later releases

Requirements

Requirement Value

Client

Requires Windows Vista or Windows XP.

Server

Requires Windows Server 2008 or Windows Server 2003.

Header

Declared in Esent.h.

See Also

JET_API_PTR
JET_CALLBACK
JET_CBTYP
JetCreateInstance
JetInit
JetSetLS