Timed Entry Calls
Author: JTC1/SC22/WG9/ARG, by Randall Brukardt, ARG Editor

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# 9.7.2 Timed Entry Calls

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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.

#### Syntax

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timed_entry_call ::=
select
entry_call_alternative
or
delay_alternative
end select;
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entry_call_alternative ::=
entry_call_statement [sequence_of_statements]

#### Dynamic Semantics

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For the execution of a timed_entry_call, the entry_name and the actual parameters are evaluated, as for a simple entry call (see 9.5.3). The expiration time (see 9.6) for the call is determined by evaluating the delay_expression of the delay_alternative; the entry call is then issued.
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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 of the delay_alternative is executed; if the entry call completes normally, the optional sequence_of_statements of the entry_call_alternative is executed.

#### Examples

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Example of a timed entry call:
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`select
Controller.Request(Medium)(Some_Item);
or
delay 45.0;
-- controller too busy, try something else
end select;`

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