When the list form of the PUTLINE macro instruction expands, it builds a three-word PUTLINE parameter block (PTPB). The list form of the macro instruction initializes the PTPB according to the operands you have coded in the macro instruction. The initialized block, which you can later modify with the execute form of the PUTLINE macro instruction, indicates to the PUTLINE service routine the function you want performed. You must supply the address of the PTPB to the execute form of the PUTLINE macro instruction. Because the list form of the macro instruction expands into a PTPB, all you need do is pass the address of the list form of the macro instruction to the execute form as the PARM value.

The PUTLINE parameter block is defined by the IKJPTPB DSECT, which is provided in SYS1.MACLIB. Table 1 describes the contents of the PTPB.