Wait External Command

The WAIT EXTERNAL command
Use this command when you want to wait on events that post MVS-format ECBs. If a WAIT EXTERNAL ECB is hand posted, for example by another task moving a value into the ECB, unpredictable errors occur. If there is any possibility of hand posting, use the WAITCICS command. Use WAIT EXTERNAL whenever possible, because it usually has less overhead.

A given ECB must not be waited on by more than one task at the same time. If this rule is not followed, the second task to wait on the ECB gets an INVREQ condition.


EXEC CICS
WAIT EXTERNAL ECBLIST(ptr-value)
NUMEVENTS(data-value)
NAME(name)
END EXEC


Options
ECBLIST(ptr-value) Is a pointer to a list of addresses of MVS-format ECBs representing events. Both the ECBLIST and the ECBs can be above the 16MB line, that is they can be 31-bit addresses. Each ECB must be fullword aligned. Null (X'00000000' and X'FF000000') ECB addresses are ignored.
NAME(name) Specifies the symbolic name, 1-8 alphanumeric characters, that is returned in SUSPENDVALUE or HVALUE, when a task issues WAIT EXTERNAL and is the subject of an INQ TASK command or a CEMT INQ TASK.
NUMEVENTS(data-value) Is the number of such events, corresponding to the number of addresses in the ECBLIST. The field is fullword binary. When NUMEVENTS is specified as 1, ECBLIST must still be an address that points to a list containing just one ECB address.
Conditions
INVREQ
  1. An ECB is not valid, for example the ECB is not fullword aligned.
  2. The ECB address is a null pointer, (X'00000000'). or (X'FF000000').
  3. NUMEVENTS is not a positive number.
  4. No valid ECBs have been found in the list, because either the ECBLIST address is not valid or all the ECB addresses are not valid.
  5. The ECBs specified are in read-only storage.
Default action: terminate the task abnormally.

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