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<H1> A.8.4 The Generic Package Direct_IO</H1>
<H4 ALIGN=CENTER>Static Semantics</H4>
<DIV Class="Paranum"><FONT SIZE=-2>1</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> The generic library
package Direct_IO has the following declaration: </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Examples"><TT><B>with</B> Ada.IO_Exceptions;<BR>
<B>generic</B><BR>
<B>type</B> Element_Type <B>is</B> <B>private</B>;<BR>
<B>package</B> Ada.Direct_IO <B>is</B><A NAME="I5794"></A><A NAME="I5795"></A><A NAME="I5796"></A></TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<DIV Class="Examples"><TT> <B>type</B> <A NAME="I5797"></A><A NAME="I5798"></A>File_Type <B>is</B> <B>limited</B> <B>private</B>;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<DIV Class="Examples"><TT> <B>type</B> <A NAME="I5799"></A><A NAME="I5800"></A>File_Mode <B>is</B> (In_File, Inout_File, Out_File);<BR>
<B>type</B> <A NAME="I5801"></A><A NAME="I5802"></A>Count <B>is</B> <B>range</B> 0 .. <I>implementation-defined</I>;<BR>
<B>subtype</B> <A NAME="I5803"></A>Positive_Count <B>is</B> Count <B>range</B> 1 .. Count'Last;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<DIV Class="Examples"><TT> --<I> File management</I></TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5804"></A><A NAME="I5805"></A>Create(File : <B>in</B> <B>out</B> File_Type;<BR>
Mode : <B>in</B> File_Mode := Inout_File;<BR>
Name : <B>in</B> String := "";<BR>
Form : <B>in</B> String := "");</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5806"></A><A NAME="I5807"></A>Open (File : <B>in</B> <B>out</B> File_Type;<BR>
Mode : <B>in</B> File_Mode;<BR>
Name : <B>in</B> String;<BR>
Form : <B>in</B> String := "");</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5808"></A><A NAME="I5809"></A>Close (File : <B>in</B> <B>out</B> File_Type);<BR>
<B>procedure</B> <A NAME="I5810"></A><A NAME="I5811"></A>Delete(File : <B>in</B> <B>out</B> File_Type);<BR>
<B>procedure</B> <A NAME="I5812"></A><A NAME="I5813"></A>Reset (File : <B>in</B> <B>out</B> File_Type; Mode : <B>in</B> File_Mode);<BR>
<B>procedure</B> <A NAME="I5814"></A><A NAME="I5815"></A>Reset (File : <B>in</B> <B>out</B> File_Type);</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>9</FONT></DIV>
<DIV Class="Examples"><TT> <B>function</B> <A NAME="I5816"></A><A NAME="I5817"></A>Mode (File : <B>in</B> File_Type) <B>return</B> File_Mode;<BR>
<B>function</B> <A NAME="I5818"></A><A NAME="I5819"></A>Name (File : <B>in</B> File_Type) <B>return</B> String;<BR>
<B>function</B> <A NAME="I5820"></A><A NAME="I5821"></A>Form (File : <B>in</B> File_Type) <B>return</B> String;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>10</FONT></DIV>
<DIV Class="Examples"><TT> <B>function</B> <A NAME="I5822"></A><A NAME="I5823"></A>Is_Open(File : <B>in</B> File_Type) <B>return</B> Boolean;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>11</FONT></DIV>
<DIV Class="Examples"><TT> --<I> Input and output operations</I></TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>12</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5824"></A><A NAME="I5825"></A>Read (File : <B>in</B> File_Type; Item : <B>out</B> Element_Type;<BR>
From : <B>in</B> Positive_Count);<BR>
<B>procedure</B> <A NAME="I5826"></A><A NAME="I5827"></A>Read (File : <B>in</B> File_Type; Item : <B>out</B> Element_Type);</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>13</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5828"></A><A NAME="I5829"></A>Write(File : <B>in</B> File_Type; Item : <B>in</B> Element_Type;<BR>
To : <B>in</B> Positive_Count);<BR>
<B>procedure</B> <A NAME="I5830"></A><A NAME="I5831"></A>Write(File : <B>in</B> File_Type; Item : <B>in</B> Element_Type);</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>14</FONT></DIV>
<DIV Class="Examples"><TT> <B>procedure</B> <A NAME="I5832"></A><A NAME="I5833"></A>Set_Index(File : <B>in</B> File_Type; To : <B>in</B> Positive_Count);</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>15</FONT></DIV>
<DIV Class="Examples"><TT> <B>function</B> <A NAME="I5834"></A><A NAME="I5835"></A>Index(File : <B>in</B> File_Type) <B>return</B> Positive_Count;<BR>
<B>function</B> <A NAME="I5836"></A><A NAME="I5837"></A>Size (File : <B>in</B> File_Type) <B>return</B> Count;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>16</FONT></DIV>
<DIV Class="Examples"><TT> <B>function</B> <A NAME="I5838"></A><A NAME="I5839"></A>End_Of_File(File : <B>in</B> File_Type) <B>return</B> Boolean;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>17</FONT></DIV>
<DIV Class="Examples"><TT> --<I> Exceptions</I></TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>18</FONT></DIV>
<DIV Class="Examples"><TT> <A NAME="I5840"></A>Status_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Status_Error;<BR>
<A NAME="I5841"></A>Mode_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Mode_Error;<BR>
<A NAME="I5842"></A>Name_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Name_Error;<BR>
<A NAME="I5843"></A>Use_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Use_Error;<BR>
<A NAME="I5844"></A>Device_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Device_Error;<BR>
<A NAME="I5845"></A>End_Error : <B>exception</B> <B>renames</B> IO_Exceptions.End_Error;<BR>
<A NAME="I5846"></A>Data_Error : <B>exception</B> <B>renames</B> IO_Exceptions.Data_Error;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>19</FONT></DIV>
<DIV Class="Examples"><TT><B>private</B><BR>
... -- <I>not specified by the language</I><BR>
<B>end</B> Ada.Direct_IO;</TT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>19.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Reason: </B>The Element_Type
formal of Direct_IO does not have an <FONT FACE="Arial, Helvetica">unknown_discriminant_part</FONT>
(unlike Sequential_IO) so that the implementation can make use of the
ability to declare uninitialized variables of the type. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>19.a.1/1</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Implementation Note: </B>{<I><A HREF="defect2.html#8652/0097">8652/0097</A></I>}
<U>File_Type cannot be implemented as a (directly) controlled type, as
Ada.Direct_IO can be instantiated at any nesting depth. File_Type could
have a component of a controlled type, as long as that type is declared
in some other (non-generic) package.</U> </FONT></DIV>
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