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<H1> 9.9 Task and Entry Attributes</H1>
<H4 ALIGN=CENTER>Dynamic Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> For a <FONT FACE="Arial, Helvetica">prefix</FONT>
T that is of a task type [(after any implicit dereference)], the following
attributes are defined: </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DL Class="Hanging"><DT> T'Callable<DD Class="Hanging">
<A NAME="I3823"></A><A NAME="I3824"></A>Yields the value True when the
task denoted by T is <I>callable</I>, and False otherwise; <A NAME="I3825"></A><A NAME="I3826"></A>a
task is callable unless it is completed or abnormal. The value of this
attribute is of the predefined type Boolean.</DL>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DL Class="Hanging"><DT> T'Terminated<DD Class="Hanging">
<A NAME="I3827"></A><A NAME="I3828"></A>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. </DL>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<DIV Class="Normal"> For a <FONT FACE="Arial, Helvetica">prefix</FONT>
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. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<DL Class="Hanging"><DT> E'Count<DD Class="Hanging">
<A NAME="I3829"></A><A NAME="I3830"></A>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 <I>universal_integer</I>.</DL>
<DIV Class="NotesHeader"><FONT SIZE=-1>NOTES</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>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 <FONT FACE="Arial, Helvetica">direct_name</FONT>
or an expanded name.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>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 <FONT FACE="Arial, Helvetica">timed_entry_calls</FONT>.
Also, a <FONT FACE="Arial, Helvetica">conditional_entry_call</FONT> may
briefly increase this value, even if the conditional call is not accepted.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>43 Within protected units,
algorithms interrogating the attribute E'Count in the <FONT FACE="Arial, Helvetica">entry_barrier</FONT>
for the entry E should take precautions to allow for the evaluation of
the <FONT FACE="Arial, Helvetica">condition</FONT> of the barrier both
before and after queuing a given caller. </FONT></DIV>
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