Handling errors and special conditions

This chapter discusses how to analyze information for errors and special conditions and what to do, in general, when the error or special condition is identified. Identifying and acting upon errors and special conditions are discussed separately for:

OPEN or CLOSE macroinstructions
Manipulative macroinstructions
RPL-based requests (for example, SEND, RECEIVE, and CHECK).

Note: For a description of the software error analysis that is operating-system-dependent, refer to Error handling.

The information that VTAM® returns to the application program is organized so that a minimum amount of checking is required. For most macroinstructions, if register 15 contains 0 on return to the program, no further checking is necessary; the program proceeds normally. If register 15 contains a value other than 0, checking proceeds until the condition is defined and appropriate action is taken. For certain RPL-based macroinstructions, register 0 must be examined for a special condition even if register 15 contains 0.