Parameter Lists for VSE/VSAM Macros

The VSE/VSAM control block (CB) manipulation macros (GENCB, MODCB, SHOWCB, and TESTCB) use an internal parameter list to describe the actions that you specify when you code the macros. The BLDVRP macro (for building a VSE/VSAM resource pool) and the SHOWCAT macro (which displays catalog information) also use an internal parameter list to indicate the addresses and values that you specify when you code the macros.

Depending on the form of the macro, the internal parameter list is built as follows:
  • The standard form of these macros builds a parameter list in-line and processes it.
  • The list form builds a parameter list in an area you specified.
  • The execute form processes a previously built parameter list.
  • The generate form (not for BLDVRP and SHOWCAT) builds a parameter list in an area you specify and also processes it.

(Use of the different forms are discussed under List, Execute, and Generate Forms of the Control Block Manipulation Macros.)

For special purposes, such as developing high-level programming languages, you may want to build and process parameter lists without using the macros. The following describes the format of the parameter lists and gives the codes used for the operands of each of the macros. The formats and codes are fixed, so that you can build and alter them by your own methods. For the control block manipulation macros, a parameter list contains a variable number of entries of three types:
  • Type 1: At the beginning of the list, addresses of entries of Type 2 and Type 3. The addresses are fullwords, and the high-order bit of the last fullword is 1.
  • Type 2: A header entry containing general information about the block or list that you want to generate, modify, display or test.
  • Type 3: At the end of the list, keyword entries describing each field that you want to generate, modify, display, or test.

In the following, entries of Type 2 and Type 3 are described separately for GENCB, MODCB, SHOWCB, and TESTCB. When VSE/VSAM receives control, register 1 must point to your parameter list.

The format of the BLDVRP and SHOWCAT parameter lists is different from the above scheme. Refer to The BLDVRP Parameter List and The SHOWCAT Parameter List.