If a specified area is not reserved for use as a buffer pool, or if you want to delay specifying the number and length of the buffers until execution of your program, you can use the GETPOOL macro. This macro allows you to vary the size and number of buffers according to the needs of the data set being processed. The storage resides below the line in subpool zero.

The GETPOOL macro causes the system to allocate a virtual storage area to a buffer pool. The system builds a buffer pool control block and stores its address in the data set's DCB. If you choose to issue the GETPOOL macro, issue it either before opening the data set or during your DCB's OPEN exit routine.

When using GETPOOL with QSAM, specify a buffer length (BUFL) at least as large as the block size or omit the BUFL parameter.