The assembler calls the exit with a request type of 4 (WRITE) when the exit is writing the listing records. The buffer pointer field points to the listing record, and the buffer length contains the length of the record.

z/VM and z/OS

Depending on the setting of the ASA assembler option, the record has either an American National Standard or a machine printer control character at the start of the record.

The options field contains a value that represents the type of listing record that is passed. The listing record types, and their corresponding options values, are shown in For the LISTING exit.

The user exit should maintain the absolute record number and the relative record number. These fields are set to zero before the OPEN request. The assembler uses the relative record number and the linecount value to determine when to start a new page in the assembler listing. A new page is started when the relative record number exceeds the line count.