Buffer List Entry

A buffer list contains one or more entries in contiguous storage. Each entry provides the buffer address, the length of the DSCB buffer, the argument, and indicates whether the argument is an RBA, a TTR, or a CCHHR. The fields and bit uses are listed below.

For a DSCB buffer, the RBA bit must be 0, and either the TTR or CCHHR bits must be set to 1 (they must not both be 1).
The BFLESKIP bit causes an entry to be ignored.
The BFLEIOER bit is an output indicator from CVAF that indicates an I/O error occurred during reading or writing of the DSCB.
The BFLELTH field is the length of the buffer; for a DSCB buffer, the length must be 96 or 140.
The BFLEARG field is the argument (address) of the DSCB. Specify the format of the 5-byte field by setting the BFLECHR, BFLETTR, or BFLERBA bit to 1. The respective BFLEARG values and formats are as follows:
Value Format
CCHHR 5-byte CCHHR
TTR 0TTR0
RBA 1 byte of 0 followed by a 4-byte relative byte address.

The values for BFLEARG depend on the variables associated with a given request. These are described in the following request-oriented topics.

The format of the buffer list entry is shown in Table 1.

Table 1. Format of a Buffer List Entry
Offset	Length or Bit Pattern	Name	Description
0 (X'00')	12	BFLE	Buffer list entry.
0 (X'00')	1	BFLEFL	Flag byte.
	100 . . . . .	BFLERBA	Argument is RBA.
	010 . . . . .	BFLECHR	Argument is CCHHR.
	001 . . . . .	BFLETTR	Argument is TTR.
	. . . 1 . . . .	BFLEAUPD	CVAF updated argument field.
	. . . . 1 . . .	BFLEMOD	Data in buffer has been modified.
	. . . . . 1 . .	BFLESKIP	Skip this entry.
	. . . . . . 1 .	BFLEIOER	I/O error.
	. . . . . . . 1	BFLENOVR	If using CVAFDIR to write a 96-byte DSCB, bypass comparing the DSCB key to the data set name.
1 (X'01')	1	BFLEFLG2	Flag byte 2.
	1 . . . . . . .	BFLENVER	When using CVAFDIR to write multiple DSCBs and this flag is set, CVAF will not verify that the existing DSCB is format 0 prior to writing this DSCB. This overrides VERIFY=YES on CVAFDIR (CV2VER) for this buffer list entry.
	. x x x x x x x		Reserved.
2 (X'02')	1	BFLELTH	Length of DSCB buffer.
3 (X'03')	5	BFLEARG	Argument of DSCB.
4 (X'04')	3	BFLEATTR	TTR of DSCB.
4 (X'04')	4	BFLEARBA	Reserved.
8 (X'08')	4	BFLEBUF	Buffer address.