z/OS DFSMStvs Administration Guide
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SHOWCAT—standard form

z/OS DFSMStvs Administration Guide
GC52-1388-00

The format of the SHOWCAT macro follows.

The format of the SHOWCAT macro.
Label Operand Parameters

[label]

SHOWCAT

[ACB=address]
[AREA=
address]
[{CI=
address|NAME=address}]

label
specifies 1 to 8 characters that provide a symbolic address for the SHOWCAT macro.
ACB=address
specifies the address of the access method control block that defines the catalog containing the entry from which to display information. You issue the first SHOWCAT without ACB specified and VSAM supplies it to you for the next SHOWCAT (see the description of the work area under the AREA operand). Specifying ACB enables VSAM to go directly to the correct catalog without searching other catalogs first. You should always specify ACB when specifying CI instead of NAME.
AREA=address
specifies the address of the work area in which to display the catalog information. The first 2 bytes of the area must give the length of the area, including the 2 bytes. The minimum is 64. If the area is too small, VSAM returns as much information as possible.

You can use the IGGSHWPL macro to generate a DSECT statement and labels for the fields in the work area.

The format of the work area follows.

The format of the work area for the IGGSHWPL macro.
Offset Length Symbolic Name Description
0(X'00') 2 SHWLEN1 Length of the area, including the length of this field (provided by you).
2(X'02') 2 SHWLEN2 Length of the area used by VSAM, including the length of this field and the preceding field.
4(X'04') 4 SHWACBP The address of the ACB that defines the catalog that contains the entry from which information is displayed.
8(X'08') 1 SHWTYPE Type of object about which information is returned:
C
Cluster
D
Data component
G
Alternate index
I
Index
R
Path
Y
Upgrade set

The following fields contain one set of information for C, G, R, and Y types and another set for D and I types:

The format of the work area for C, G, R, and Y types follows.

The format of the work area for C, G, R, and Y types.
Offset Length or Bit Pattern Symbolic Name Description
9(X'09') 1 SHWATTR For C and Y types: reserved.
      For G type:
  x... .... SHWUP The alternate index may (1) or may not (0) be a member of an upgrade set. One way of verifying this is to display information for the upgrade set of the base cluster and check whether it contains control interval numbers of entries that describe the components of the alternate index. Figure 1 shows how to get from the alternate index's catalog entry to the entries that describe its components (G to C to D to Y to D and I).
  .xxx xxxx   Reserved.
      For R type:
  x... .... SHWUP The path is (1) or is not (0) defined for upgrading alternate indexes.
  .xxx xxxx   Reserved.
10(X'0A') 2 SHWASS0 The number of association pointers that follow.
    SHWACT Each association pointer identifies another catalog entry that describes an object associated with this C, G, R, or Y object. The possible types of associated objects are:
  • With C: D, G, I, R.
  • With G: C, D, G, I.
  • With R: C, D, G, I.
  • With Y: D, I.

Figure 1 shows how the catalog entries for all these objects are interrelated.

12(X'0C') 1 SHWATYPE Type of object the entry describes.
13(X'0D') 3 SHWAC1 The control interval number of its first record.
16(X'10')     Next association pointer, and so on. For type Y, if the area is too small to display an association pointer for each associated object, VSAM displays as many pointers as possible and returns a code of 4 in register 15. For types C and G, if the area is too small, VSAM displays as many pointers as possible, but returns as a code of 0 in register 15 because fields for the main associated objects can always be displayed (in the smallest allowed work area). For type R, fields for all associated objects (five possible) can always be displayed.

(An associated pointer occupies 4 bytes (1 byte for the associated entry type and 3 bytes for its control interval number). However, for all types except Y, 4 additional bytes are required as work space for the SHOWCAT processor. For example, if you provide 80 bytes for associated objects, as many as 10 association pointers can be displayed for type C or G and 20 for type Y.)

The format of the work area for D and I types follows.

The format of the work area for D and I types.
Offset Length Symbolic Name Description
9(X'09') 1   Reserved.
10(X'0A') 2 SHWDSB Relative position of the prime key in records in the data component.
    SHWRKP For the data component of an ESDS, there is no prime key and this field is 0.
12(X'0C') 2 SHWKEYLN Length of the prime key.
14(X'0E') 4 SHWCISZ Control interval size of the data or index component.
18(X'12') 4 SHWMREC Maximum record size of the data or index component.
22(X'16') 2 SHWASS The number of association pointers that follow.
    SHWACT Each association pointer identifies another catalog entry that describes an object associated with this D or I object. The possible types of associated objects are:
  • With D: C, G, Y.
  • With I: C, G.
Figure 1 shows how the catalog entries for all these objects are interrelated.
24(X'18') 1 SHWATYPE Type of object the entry describes.
25(X'19') 3 SHWACI The control interval number of its first record.
28(X'1C')     Next association pointer, and so on. Fields for all associated objects can always be displayed.
{CI=address|NAME=address}
specifies the address of an area that identifies the catalog entry containing the desired information.
CI=address
specifies the area is 3 bytes long and contains the control interval number (RBA divided by 512) of the first record in the catalog entry. You can issue the first SHOWCAT with NAME specified, and then VSAM supplies control interval numbers to you for other SHOWCATs (see the description of the work area under the AREA operand). The type of object named must be C, D, G, I, R, or Y. The 3-byte area must be separate from the work area, even though VSAM returns a control interval number in the work area.
NAME=address
specifies the area is 44 bytes long and contains the name of the object described by the entry. The name is left-justified and padded with blanks. The type of object named must be C, D, G, I, or R.

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