About records
Records for different services are different in details, but follow the same overall structure.
The read function returns one record at a time. If there is no record, the read function waits until a record becomes available.
Each record begins with a 4-byte field that contains the length
of the remaining record. The remaining record contains the binary z/VM® data followed by the four bytes
X'454f5200' to mark the end of the record. These bytes build the zero-terminated
ASCII string EOR
, which is useful as an eye catcher.
Figure 1 illustrates the structure of a complete record as returned by the device. If the buffer assigned to the read function is smaller than the overall record size, multiple reads are required to obtain the complete record.
The format of the z/VM data (*LOGREC) depends on the record type that is described in the common header for error records HDRREC.
For more information about the z/VM record layout, see the CMS and CP Data Areas and Control Blocks documentation at www.ibm.com/vm/pubs/ctlblk.html.