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

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# 9.7.3 Conditional Entry Calls

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A conditional_entry_call issues an entry call that is then cancelled if it is not selected immediately (or if a requeue-with-abort of the call is not selected immediately).

#### Syntax

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conditional_entry_call ::=
select
entry_call_alternative
else
sequence_of_statements
end select;

#### Dynamic Semantics

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The execution of a conditional_entry_call is defined to be equivalent to the execution of a timed_entry_call with a delay_alternative specifying an immediate expiration time and the same sequence_of_statements as given after the reserved word else.
NOTES
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37 A conditional_entry_call may briefly increase the Count attribute of the entry, even if the conditional call is not selected.

#### Examples

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Example of a conditional entry call:
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`procedure Spin(R : in Resource) is
begin
loop
select
R.Seize;
return;
else
null; -- busy waiting
end select;
end loop;
end;`

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