This function is used to generate an item access descriptor that can be subsequently used to extract data from a bundle.
bc parameter should be a bundle descriptor
reference as returned by a
entag parameter identifies the information
to be accessed. The simplest form consists of passing a simple 16-bit
(non-zero) tag identifier, used when the
application requires access to the item data.
The CYG_BUNDLE_ARBITRARY flag can be OR-ed with the tag value to request access to any “arbitrary” data that may be associated with the requested tag item. When using CYG_BUNDLE_ARBITRARY then a 0x0000 tag value is acceptable, and is used to reference the parent bundle “arbitrary” data.
Pointer to the required object descriptor, or NULL if unable to find
the data described by the
entag or if an
entag value was used.