IMSAdminBase::ChangePermissions

The IMSAdminBase;:ChangePermissions method changes permissions on an open handle. If the handle was opened with write permission and you change it to read only, this method will cause any callback methods registered to be called.

HRESULT ChangePermissions(
  METADATA_HANDLE hMDHandle,  //metabase handle
  DWORD dwMDTimeOut,          //time, in milliseconds, for the 
                              // method to wait before failing
  DWORD dwMDAccessRequested   //specifies the new permissions for 
                              // the handle
);

Parameters

hMDHandle

Specifies a handle to the metabase, as returned by the IMSAdminBase::OpenKey method.

dwMDTimeOut

Specifies the time, in milliseconds, for the method to wait for the operation to succeed.

dwMDAccessRequested

Specifies the new permissions for the handle. It must be at least one of the following values:

Value	Description
METADATA_PERMISSION_READ	Open the key for reading.
METADATA_PERMISSION_WRITE	Open the key for writing.

Return Values

Returns an HRESULT that contains one of the following values:

ERROR_INVALID_HANDLE	The metabase handle is invalid.
ERROR_PATH_BUSY	The path specified cannot be used at this time.
ERROR_SUCCESS	The method succeeded

Remarks

When you use this method to add permissions, success or failure follows the same rules as apply in IMSAdminBase::OpenKey. Timeout values should be short for this call; it is quite possible for two threads with read permission on the same data to attempt to update to write permission at the same time. Both will block until one read handle is closed.