RDJFCB

Format

Read syntax diagramSkip visual syntax diagramlabelRDJFCB(, dcb_address,INPUT(INPUT)OUTPUT(OUTPUT)UPDAT(UPDAT))

Purpose

The RDJFCB macro causes information about a file defined by the FILEDEF command to be moved into the user's area as identified through the EXLST parameter of the DCB macro for each data control block specified.

Parameters

dcb_address
is the address of the data control block associated with the file for which the JFCB is to be read. The parameters INPUT, OUTPUT, and UPDAT do not affect RDJFCB processing.
INPUT
Indicates that your file is to be treated as an input file. Unless otherwise specified, this parameter applies by default.
OUTPUT
Indicates that your file is to be treated as an output file.
UPDAT
Indicates that you intend to update an already existing file.

Usage

  1. An exit list address must be provided in each DCB specified by an RDJFCB macro.
  2. Each exit list must contain an active entry that specifies the virtual storage address of the area into which the returned information is to be placed.
  3. The exit list entry of 4 bytes must contain a X'07' in byte 0 indicating the 3 byte address, which follows is the address of the user buffer where the information will be returned.
  4. The low-order 3 bytes contains the address of a 176 byte area to receive the returned information.
  5. The area must be located within the user's storage, and must be located below the 16 MB line.
  6. The virtual storage area into which the returned information is read must be at least 176 bytes long.
  7. Each exit list entry must be 4 bytes long.
  8. The system recognizes only the first occurrence of an X'07' exit list entry code.
  9. The end of the exit list is indicated by setting the high order bit in the entry code to 1.

Return Codes and ABEND Codes

Register 15 contains a return code from the RDJFCB macro, which is always 0.

Several conditions will cause the RDJFCB function to terminate abnormally with a X'240' ABEND. The reason codes and their meanings are as follows:

Hex
Code
Decimal
Code
Meaning
X'04' 4 Parameter list or DCB address is invalid.
X'08' 8 No EXLST address was found in the DCB.
X'0C' 12 No address exit was specified in the DCB exit list.
X'10' 16 The return information buffer is not within the user's storage.
Only fields provided by the RDJFCB function are programming interfaces.
  • Some or all of the following fields may be filled in depending on characteristics of the data set at the time the RDJFCB is issued.
Table 1. Information returned by RDJFCB for BSAM/QSAM
Dec (Hex)
Description
Length
0 (0)
Data set name, left justified, padded with blanks.

File name 8 bytes
File type 8 bytes
File mode 2 bytes
44X
87 (57)
Indicator byte

X'C0' - Data set does not exist
X'80' - DISP MOD specified on FILEDEF
X'40' - Data set exists
1X
99 (63)
Data organization byte

X'00' - Not a VSAM data set.
1X
104 (68)
Logical record length
2X

 

Table 2. Information returned by RDJFCB for VSAM
Dec (Hex)
Description
Length
87 (57)
Indicator byte

X'C0' - Always set to new for VSAM.
1X
99 (63)
Data organization byte.

X'08' - Indicates VSAM data set.
1X
  • Usage Note: A DCB must always be used with RDJFCB. If the DDNAME in the DCB is a VSAM data set and a DLBL has been issued, then the information returned will be as described under VSAM.