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<H1> 6.4.1 Parameter Associations</H1>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal"> <A NAME="I3013"></A>A parameter association defines
the association between an actual parameter and a formal parameter. </DIV>
<H4 ALIGN=CENTER>Name Resolution Rules</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal"> The <I>formal_parameter_</I><FONT FACE="Arial, Helvetica">selector_name</FONT>
of a <FONT FACE="Arial, Helvetica">parameter_association</FONT> shall
resolve to denote a <FONT FACE="Arial, Helvetica">parameter_specification</FONT>
of the view being called.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DIV Class="Normal"> <A NAME="I3014"></A>The <I>actual parameter</I>
is either the <FONT FACE="Arial, Helvetica">explicit_actual_parameter</FONT>
given in a <FONT FACE="Arial, Helvetica">parameter_association</FONT>
for a given formal parameter, or the corresponding <FONT FACE="Arial, Helvetica">default_expression</FONT>
if no <FONT FACE="Arial, Helvetica">parameter_association</FONT> is given
for the formal parameter. <A NAME="I3015"></A>The expected type for an
actual parameter is the type of the corresponding formal parameter. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<DIV Class="Normal"> If the mode is <B>in</B>, the actual is interpreted
as an <FONT FACE="Arial, Helvetica">expression</FONT>; otherwise, the
actual is interpreted only as a <FONT FACE="Arial, Helvetica">name</FONT>,
if possible. </DIV>
<H4 ALIGN=CENTER>Legality Rules</H4>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<DIV Class="Normal"> If the mode is <B>in out</B> or <B>out</B>, the
actual shall be a <FONT FACE="Arial, Helvetica">name</FONT> that denotes
a variable. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Normal"> The type of the actual parameter associated with
an access parameter shall be convertible (see <A HREF="RM-4-6.html">4.6</A>)
to its anonymous access type. <A NAME="I3016"></A></DIV>
<H4 ALIGN=CENTER>Dynamic Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> <A NAME="I3017"></A>For
the evaluation of a <FONT FACE="Arial, Helvetica">parameter_association</FONT>:
</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>The actual parameter is first evaluated.</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>9</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>For an access parameter, the <FONT FACE="Arial, Helvetica">access_definition</FONT>
is elaborated, which creates the anonymous access type.</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>10</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>For a parameter (of any mode) that is passed by reference
(see <A HREF="RM-6-2.html">6.2</A>), a view conversion of the actual
parameter to the nominal subtype of the formal parameter is evaluated,
and the formal parameter denotes that conversion. <A NAME="I3018"></A></LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>11</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC><A NAME="I3019"></A>For an <B>in</B> or <B>in out</B> parameter
that is passed by copy (see <A HREF="RM-6-2.html">6.2</A>), the formal
parameter object is created, and the value of the actual parameter is
converted to the nominal subtype of the formal parameter and assigned
to the formal. <A NAME="I3020"></A></LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>12</FONT></DIV>
<UL Class="Bulleted" Style="margin-bottom: 0.3em"><LI TYPE=DISC>For an <B>out</B> parameter that is passed by copy, the
formal parameter object is created, and: </LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>13</FONT></DIV>
<UL Class="CodeIndentedBulleted"><LI TYPE=DISC>For an access type, the formal parameter is initialized
from the value of the actual, without a constraint check; </LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>14</FONT></DIV>
<UL Class="CodeIndentedBulleted"><LI TYPE=DISC>For a composite type with discriminants or that has implicit
initial values for any subcomponents (see <A HREF="RM-3-3-1.html">3.3.1</A>),
the behavior is as for an <B>in out</B> parameter passed by copy. </LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>15</FONT></DIV>
<UL Class="CodeIndentedBulleted"><LI TYPE=DISC>For any other type, the formal parameter is uninitialized.
If composite, a view conversion of the actual parameter to the nominal
subtype of the formal is evaluated (which might raise Constraint_Error),
and the actual subtype of the formal is that of the view conversion.
If elementary, the actual subtype of the formal is given by its nominal
subtype. </LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>16</FONT></DIV>
<DIV Class="Normal"> <A NAME="I3021"></A><A NAME="I3022"></A>A formal
parameter of mode <B>in out</B> or <B>out</B> with discriminants is constrained
if either its nominal subtype or the actual parameter is constrained.</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>17</FONT></DIV>
<DIV Class="Normal"> <A NAME="I3023"></A><A NAME="I3024"></A><A NAME="I3025"></A><A NAME="I3026"></A><A NAME="I3027"></A>After
normal completion and leaving of a subprogram, for each <B>in out</B>
or <B>out</B> parameter that is passed by copy, the value of the formal
parameter is converted to the subtype of the variable given as the actual
parameter and assigned to it. <A NAME="I3028"></A>These conversions and
assignments occur in an arbitrary order. </DIV>
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