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9.9 Task and Entry Attributes
Dynamic Semantics
For a prefix T that is of a task type (after any implicit dereference),
the following attributes are defined:
T'Callable
Yields the value True when the task denoted by T is callable,
and False otherwise; a task is callable unless it is
completed or abnormal. The value of this attribute is of the
predefined type Boolean.
T'Terminated
Yields the value True if the task denoted by T is terminated,
and False otherwise. The value of this attribute is of the
predefined type Boolean.
For a prefix E that denotes an entry of a task or protected unit, the
following attribute is defined. This attribute is only allowed within the
body of the task or protected unit, but excluding, in the case of an entry of
a task unit, within any program unit that is, itself, inner to the body of
the task unit.
E'Count
Yields the number of calls presently queued on the entry E of
the current instance of the unit. The value of this
attribute is of the type universal_integer.
NOTES
(41) For the Count attribute, the entry can be either a single entry or
an entry of a family. The name of the entry or entry family can be
either a direct_name or an expanded name.
(42) Within task units, algorithms interrogating the attribute E'Count
should take precautions to allow for the increase of the value of this
attribute for incoming entry calls, and its decrease, for example with
timed_entry_calls. Also, a conditional_entry_call may briefly increase
this value, even if the conditional call is not accepted.
(43) Within protected units, algorithms interrogating the attribute
E'Count in the entry_barrier for the entry E should take precautions to
allow for the evaluation of the condition of the barrier both before and
after queuing a given caller.
About DocAda Light:
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Complete RM95
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