Description

A READ_LIST request allows you to read multiple entries from a single list into the storage areas specified by ANSAREA and/or BUFLIST or BUFFER and/or ADJAREA.

Entries are read in sequence from a starting list entry to the head or tail of the list on which the starting entry resides. The direction of processing (toward the head or toward the tail) depends on the direction you specify on the LISTDIR parameter. The starting entry must exist or the request fails.

For each processed entry, any combination of the following types of data can be read depending on what you specify on the TYPE parameter:

List entry controls
Entry data
Adjunct data

Additionally, you can perform locking functions with a READ_LIST request by specifying LOCKOPER. The lock designated by LOCKINDEX will be operated on as specified by LOCKOPER.

With a coupling facility of CFLEVEL=1 or higher, the following additional functions are supported for a READ_LIST request:

You can specify that each list entry is to be read only after a successful comparison of the list authority value for the target list with a user-specified value. You specify the list authority comparison requirements using AUTHCOMP and AUTHCOMPTYPE. If the request is successful, you also can update the list authority value to a new value that you specify with NEWAUTH.
You can specify that a list entry is to be read only after a successful comparison of the entry key value with a user-specified value (KEYCOMP). If the comparison is not successful, the current list entry is not read and processing continues with the next entry to be considered.
Version number comparison also is enhanced to allow for an additional less-than-or-equal comparison operation.