Retrieving Information from a Catalog

To read an entry from a catalog, use the LOCATE and CAMLST macro instructions. You can specify the entry to be read into your output area using the following information:

The fully- or partially-qualified name of a data set
The relative block address of the block containing the entry.

If you specify a fully-qualified data set name, a list of volumes on which the data set resides is read into your output area. This volume list always begins with a 2-byte entry indicating the number of volumes in the list.

Restriction: When CAMLST is used to locate a data set that is over 20 volumes in length, only information from the first 20 volumes is returned. If you need to retrieve data from more than 20 volumes, use IGGCSI (Catalog Search Interface). See (link to pertinent section in Man Cat).

For the Catalog interface, a fully-qualified name is one which represents a single data set. A partially-qualified name is one which may contain multiple qualifiers, but does not specify a full data set name.

For example, if LEVEL1.LEVEL2.LEVEL3.LEVEL4 is a data set, then LEVEL1.LEVEL2.LEVEL3.LEVEL4 is a fully-qualified name. The following data set would be considered partially-qualified names:

LEVEL1.LEVEL2.LEVEL3
LEVEL1.LEVEL2
LEVEL1

Restriction: For the catalog interface, you cannot specify an asterisk (*) or an ampersand (&) to specify a partially-qualified data set name.

See z/OS DFSMSdfp Diagnosis for descriptions of the contents of the volume control block and the other catalog data areas.

See Return Codes from LOCATE for a description of the LOCATE return codes.