|
Fetch raw data pointer for a particular subfield of this field.
The passed DDFSubfieldDefn (poSFDefn) should be acquired from the DDFFieldDefn corresponding with this field. This is normally done once before reading any records. This method involves a series of calls to DDFSubfield::GetDataLength() in order to track through the DDFField data to that belonging to the requested subfield. This can be relatively expensive.
-
Parameters:
-
| poSFDefn |
The definition of the subfield for which the raw data pointer is desired. |
| pnMaxBytes |
The maximum number of bytes that can be accessed from the returned data pointer is placed in this int, unless it is NULL. |
| iSubfieldIndex |
The instance of this subfield to fetch. Use zero (the default) for the first instance. |
-
Returns:
-
A pointer into the DDFField's data that belongs to the subfield. This returned pointer is invalidated by the next record read (DDFRecord::ReadRecord()) and the returned pointer should not be freed by the application.
|