1/2
A timed_entry_call issues an entry call that is cancelled if the call (or a requeue−with−abort of the call) is not selected before the expiration time is reached. A procedure call may appear rather than an entry call for cases where the procedure might be implemented by an entry.
2
timed_entry_call::=
select
entry_call_alternative
or
delay_alternative
end select;
3/2
entry_call_alternative::=
procedure_or_entry_call [sequence_of_statements]
3.1/2
procedure_or_entry_call::=
procedure_call_statement | entry_call_statement
3.2/2
If a procedure_call_statement is used for a procedure_or_entry_call, the procedure_name or procedure_prefix of the procedure_call_statement shall statically denote an entry renamed as a procedure or (a view of) a primitive subprogram of a limited interface whose first parameter is a controlling parameter (see 3.9.2).
3.3/2
If a procedure_call_statement is used for a procedure_or_entry_call, and the procedure is implemented by an entry, then the procedure_name, or procedure_prefix and possibly the first parameter of the procedure_call_statement, determine the target object of the call and the entry to be called.
4/2
For the execution of a timed_entry_call, the entry_name, procedure_name, or procedure_prefix, and any actual parameters are evaluated, as for a simple entry call (see 9.5.3) or procedure call (see 6.4). The expiration time (see 9.6) for the call is determined by evaluating the delay_expression of the delay_alternative. If the call is an entry call or a call on a procedure implemented by an entry, the entry call is then issued. Otherwise, the call proceeds as described in 6.4 for a procedure call, followed by the sequence_of_statements (see 5.1) of the entry_call_alternative (see 9.7.2); the sequence_of_statements (see 5.1) of the delay_alternative (see 9.7.1) is ignored.
5
If the call is queued (including due to a requeue−with−abort), and not selected before the expiration time is reached, an attempt to cancel the call is made. If the call completes due to the cancellation, the optional sequence_of_statements (see 5.1) of the delay_alternative (see 9.7.1) is executed; if the entry call completes normally, the optional sequence_of_statements (see 5.1) of the entry_call_alternative (see 9.7.2) is executed.
6
Example of a timed entry call:
7
select Controller.Request(Medium)(Some_Item); or delay 45.0; −− controller too busy, try something else end select;