ABAPWAIT_APC - WAIT APC

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WAIT FOR PUSH CHANNELS

Short Reference

WAIT FOR PUSH CHANNELS
         $[MESSAGING CHANNELS$]
         $[ASYNCHRONOUS TASKS$]
         UNTIL log_exp $[UP TO sec SECONDS$].

Additions

1. ... MESSAGING CHANNELS

2. ... ASYNCHRONOUS TASKS

3. ... UP TO sec SECONDS

Effect

This variant of the statement WAIT is only intended for use in client programs of ABAP Push Channels. Any logical expression can be specified for log_exp after UNTIL.

• If the result of log_exp is false and a receiver is registered for APC messages, the program waits until an ON_MESSAGE method is executed for a message sent by a sender program and then checks the logical expression again:

• If the new check on the result of the logical expression is true, sy-subrc is set to 0 and the execution of the program is continued with the statement that follows WAIT.

• If the new check on the result of the logical expression is false and the ON_MESSAGE methods of all previously sent messages have not yet been executed, one of the remaining ON_MESSAGE methods must be executed before the program continues.

• If the new check on the result of the logical expression is false and the ON_MESSAGE methods of all previously sent messages were executed, sy-subrc is set to 4 and the execution of the program is continued with the statement that follows WAIT.

• If the result of log_exp is false and no receiver is registered for APC messages, the execution of the program is not interrupted, regardless of the result of log_exp, and sy-subrc is set to the value 4.

• If the logical expression is true, the execution of the program is not interrupted, regardless of whether a receiver is registered for APC messages, and sy-subrc is set to the value 0.

If the statement WAIT interrupts the program, the work process is changed, and a database commit is executed, except in updates. For this reason, WAIT must not be used between statements that open or close a database cursor.

System Fields

sy-subrc	Meaning
0	The logical expression log_exp is true.
4	The logical expression log_exp is false. Also, no receiver is registered for APC messages in the current internal session and no registrations for AMC messages or asynchronous function calls exist when the additions MESSAGING CHANNELS or ASYNCHRONOUS TASKS are used.
8	The logical expression log_exp is false and when the addition UP TO was specified, the maximum time was exceeded.

Note

If the logical expression is incorrect, the running program is stopped in its current state. After an ON_MESSAGE method, all data objects that were not changed in the ON_MESSAGE method have the same value as when the logical expression was last evaluated. Any methods called by functions within the logical expression are executed again during the next check.

Addition 1

... MESSAGING CHANNELS

Addition 2

... ASYNCHRONOUS TASKS

Effect

If these additions are specified, this variant of the statement WAIT is combined with the variants WAIT FOR MESSAGING CHANNELS or WAIT FOR ASYNCHRONOUS TASKS. The program flow described in the variants is added to the program flow described above. The WAIT statement then also waits for APC messages or for asynchronously called functions to be called and does not just wait for AMC messages.

Addition 3

... UP TO sec SECONDS

Effect

If UP TO is specified, a maximum time sec can be specified in seconds during which the statement waits for APC messages.

Exceptions

Non-Catchable Exceptions

• Cause: Negative time specified for sec.
  Runtime Error: WAIT_ILLEGAL_TIME_LIMIT
  
  

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