VTAM® enables application programs to chain together data from discontiguous storage locations and send it as one piece of data. This is done by setting the OPTCD field in the RPL to include BUFFLST or XBUFLST, or by coding OPTCD=BUFFLST or OPTCD=XBUFLST on the SEND macroinstruction. The XBUFLST option specifies an extended buffer list. See Sending and receiving data using high performance data transfer for more information.

When the BUFFLST option is used, the AREA field in the RPL no longer points to the data to be sent. Instead, it points to an area of storage containing a buffer list. The list is made up of 16-byte entries, aligned on doubleword boundaries, which contain pointers to the actual data to be sent and the length of each data item. Entries in the list, which is in contiguous storage, are processed sequentially.

The first 8 bytes of each entry are reserved and should be set to 0. The next 4 bytes contain the pointer to the data and the last 4 bytes give the length of the data.

The buffer list option has no effect on the receiving side of the conversation. The use of the buffer list option is transparent to the receiving side.