The LMGET service reads one logical record from the data set associated with the given data ID. Completion of the LMINIT and LMOPEN services for the data set is required before LMGET is invoked.
If the data to be processed is a sequential data set, the first LMGET reads the first logical record. Later invocations read successive logical records; that is, the second invocation reads the second logical record, the third invocation reads the third logical record, and so on.
If the data is an ISPF library or MVS™ partitioned data set, previous completion of the LMMFIND service is required in addition to completion of LMINIT and LMOPEN. The LMGET service reads from the last member referred to by the LMMFIND service in the data sets being processed. Thus, if LMMFIND is issued referencing member A, LMGET reads from member A. If another LMMFIND is issued referencing member B, LMGET reads from member B, not member A.
When MODE(MULTX) is used, the read operation occurs in segments (rather than in single records), with each segment comprising multiple records. Each record is prefixed by a 2-byte binary integer field containing its length. The maximum size of each segment returned is 32 000 bytes. LMGET returns data to the dataloc-var in this format:
+------+--------------+------+--------------+------+--------------+
|len | record |len | record |len | record |
+------+--------------+------+--------------+------+--------------+
<----- this length is returned in datalen-var ---->The data read is always unpacked. If the data set contains packed data, LMGET unpacks the data.