Input parameter list

Unless R1 is zero, then register 1 must contain the address of a parameter list, consisting of a list of addresses (OS linkage). Each address in the parameter list points to a parameter.
Table 1. IDISNAP input parameters

This table has three columns, except for the fifth row (starting "The following parameters"), which spans all three columns.
Parameter Number of bytes Description
Parameter 1 4 Specifies the number and type of optional parameters that follow, in the format: tnnn

where:

t
Specifies the format of parameter 3 as either:
0
To indicate that a fixed-length 140 byte parameter area is used.
N
To indicate that a variable-length null-terminated parameter area is used.
nnn
Specifies the number of parameters that follow parameter 1 as either:
000
Only parameter 1 is specified.
001
Parameters 1 and 2 are specified.
002
Parameters 1, 2, and 3 are specified.
00V
Parameters 1, 2, and 3 are specified, as well as one or more storage range address pairs in subsequent parameters.
Note: Specifying 0000 in this parameter is equivalent to invoking IDISNAP with register 1 set to zero.
Parameter 2 140 First 40 bytes is a user title, the remainder is reserved for use by Fault Analyzer. Any unused portion of the user title should be set to blanks.

The specified user title is added to the heading of the real-time report, and can be viewed and updated from the Fault Analyzer ISPF interface Fault Entry List display.

Parameter 1 must be 0001 or 0002 in order for this parameter to be processed.
Parameter 3 140 if parameter 1 is 0002, or varying if parameter 1 is N002. Fault Analyzer options. For example:
  • To prevent the creation of a history file fault entry, specify the DATASETS(IDIHIST(NULLFILE)) option.
  • To request that specific areas of storage are to be shown in the analysis report, specify the StorageRange option (see StorageRange).
  • To request the return of ENV data area information, specify the SNAPDATA option (see Using the SNAPDATA option).
Parameter 1 must be either 0002, 000V, N002, or N00V in order for this parameter to be processed:
  • If parameter 1 is 0002, then the area pointed to by this parameter must be 140 bytes, with any unused portion set to blanks.
  • If parameter 1 is N002, then the area pointed to by this parameter is a character string of varying length, which must be delimited by a null-character (X'00').
The following parameters are for pairs of storage range begin and end addresses. The maximum number of address ranges that can be specified is 160.

Using the address range parameters is an alternative to, and overrides, specification of the StorageRange option in parameter 3.

To use these extra parameters, parameter 1 must be either 000V or N00V:
  • If parameter 1 is 000V, then the area pointed to by parameter 2 must be 140 bytes, with any unused portion set to blanks.
  • If parameter 1 is N00V, then the area pointed to by parameter 2 must be 1 - 1024 bytes, with a null-character (X'00') immediately following the last character in the options string.
Parameter n 4 Storage range begin address.
Parameter n+1 4 Storage range end address.

Options that are specified in parameter 3, or implicitly via the storage range address pairs starting with parameter 4, are passed as PARM field options to the main Fault Analyzer analysis module, IDIDA.

Using the SNAPDATA option

IDISNAP also processes the SNAPDATA option (see Snapdata). SNAPDATA specifies a storage address, in an 8-byte character format, that points to a list of pointers. The list is terminated by a zero address field.

SNAPDATA parameter list shows an example of the SNAPDATA parameter list.

Figure 1. SNAPDATA parameter list
Diagram showing the format of the SNAPDATA parameter list.

Only the first pointer in the parameter list is currently used. It must be the address of a two-byte input length field followed by a buffer where IDISNAP can store the final version of the common exit environment information in the ENV data area after all exits have run. A zero length field causes Fault Analyzer to ignore the parameter. A length field shorter than the length of the ENV data area is permitted.

Review the sample members IDISNAPB (COBOL) and IDISNAPP (PL/1) for examples of how to use this feature.