The Filter Process Model

By default, Filter runs independently from the calling application process. This is called out-of-process filtering. Out-of-process filtering protects the stability of the calling application in the rare case when a malformed document causes Filter to fail. You can configure Filter to run in the same process as the calling application. This is called in-process filtering. However, it is strongly recommended you run Filter out of process whenever possible.

To monitor and debug filtering operations during out-of-process filtering, you can generate an error log at run time. See Generate an Error Log.

The following methods run in process or out of process:

Filter API

  • CanFilter
  • CanFilterEx
  • DoFilter
  • DoFilterChunk
  • GetSummaryInfo
  • GetDocFormatInfo
  • GetXmpInfo

File Extraction API

  • ExtractCloseDocument
  • ExtractGetSubFileInfo
  • ExtractGetSubFileMetadata
  • ExtractSubFile
  • ExtractGetMainFileInfo
  • ExtractOpenDocumentEx
  • GetSummaryInfo

Other Filter API methods always run in process.