IFilter::Init Method

  • Article

Initializes a filtering session.

Syntax

SCODE Init(      
    ULONG grfFlags,
    ULONG cAttributes,
    FULLPROPSPEC const *aAttributes,
    ULONG *pdwFlags
);

Parameters

  • grfFlags
    [in] Flag settings from the IFILTER_INIT enumeration for controlling text standardization, property output, embedding scope, and IFilter access patterns.
  • cAttributes
    [in] The size of the attributes array. When nonzero, cAttributes takes precedence over attributes specified in grfFlags. If no attribute flags are specified and cAttributes is zero, the default is given by the PSGUID_STORAGE storage property set, which contains the date and time of the last write to the file, size, and so on; and by the PID_STG_CONTENTS 'contents' property, which maps to the main contents of the file. For more information about properties and property sets, see Property Sets.
  • aAttributes
    [in] Array of pointers to FULLPROPSPEC structures for the requested properties. When cAttributes is nonzero, only the properties in aAttributes are returned.
  • pdwFlags
    [out] Information about additional properties available to the caller; from the IFILTER_FLAGS enumeration.

Return Value

Returns one of the following values.

S_OK Successful completion.
E_FAIL File to filter was not previously loaded.
E_INVALIDARG Count and contents of attributes do not agree.
FILTER_E_PASSWORD Access has been denied because of password protection or similar security measures.
FILTER_E_ACCESS General access failures.

Remarks

The IFilter::Init method sets the state of the filter object. The content filter positions at the beginning of the object and the object state is frozen until the object is released. You can pass the filter object the set of properties you would like returned by setting up their property set and property ID descriptions in the aAttributes array. For more information, see Filtering File Properties.

Notes to Callers

Call the Init method before calling all other IFilter methods.

Notes to Implementers

Chunk IDs must remain consistent across multiple calls to the Init method with the same parameters.

For some implementations of the IFilter interface, detection of failure to access a document may not be possible (or may be computationally expensive) until the Init method has been called, or possibly even later.

See Also

Filtering File Properties, FULLPROPSPEC, IFilter, IFILTER_FLAGS, IFILTER_INIT, PSGUID_STORAGE, Secure Code Practices