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Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 5 - Collection Manager / Collection Manager Reference

Functions / Getting Information About a Collection Item

GetCollectionItemInfo

You use the GetCollectionItemInfo function to obtain information about a specific collection item given the item's collection tag and collection ID.

OSErr GetCollectionItemInfo(Collection source,
                            CollectionTag tag,
                            long id,
                            long *index,
                            long *itemSize,
                            long *attributes);

source

A reference to the collection object containing the item you want to obtain information about.

tag

The collection tag associated with the item you want to obtain information about.

id

The collection ID associated with the item you want to obtain information about.

index

A pointer to a long value. On return, this value represents the collection index of the specified item. You may specify the constant dontWantIndex for this parameter if you do not want to determine the specified item's collection index.

itemSize

A pointer to a long value. On return, this value indicates the size in bytes of the variable-length data associated with the specified item. You may specify the constant dontWantSize for this parameter to indicate that you do not want to determine the size of this data.

attributes

A pointer to a long value. On return, this value contains a copy of the attributes associated with the specified item. You may specify the constant dontWantAttributes for this parameter if you do not want a copy of the item's attributes.

DESCRIPTION

The GetCollectionItemInfo function allows you to obtain information about a specific collection item in the collection referenced by the source parameter. You specify the collection item by specifying the item's collection tag and collection ID in the tag and id parameters.

This function returns information in the index, itemSize, and attributes parameters:

• If you provide a pointer in the index parameter, the function uses this parameter to return the collection index of the specified item. Once you have determined an item's collection index, you can use it to specify the item when calling Collection Manager functions, rather than using the item's collection tag and collection ID. Specifying collection items using their collection index, rather than using the item's collection tag and collection ID, generally results in improved performance.
• If you provide a pointer in the itemSize parameter, the function uses this parameter to return the size in bytes of the variable-length data associated with the specified collection item.
• If you provide a pointer in the attributes parameter, the function uses this parameter to return a copy of the attributes associated with the specified collection item.

RESULT CODES

collectionItemNotFoundErr

-5751

Can't locate item.

SEE ALSO

For information about collection items and their associated collection tags, collection IDs, and variable-length data, see "Collection Items" beginning on page 5-8.

For examples of this function, see "Determining the Collection Index of an Item" beginning on page 5-19, "Determining the Size of an Item's Variable-Length Data" beginning on page 5-22, and "Getting and Setting the Attributes of an Item" beginning on page 5-24.

To obtain information about a collection item using the collection index to specify the item, use the GetIndexedCollectionItemInfo function, described in the next section.

To obtain information about a collection item using the collection tag and tag list position to specify the item, use the GetTaggedCollectionItemInfo function, described on page 5-80.