<?xml version="1.0" encoding="ISO8859-1"?>
<fpdoc-descriptions>
<!--  

   $Id: ports.xml,v 1.2 2004/09/13 19:27:49 michael Exp $ 
   This file is part of the FPC documentation. 
   Copyright (C) 1997, by Michael Van Canneyt 
 
   The FPC documentation is free text; you can redistribute it and/or 
   modify it under the terms of the GNU Library General Public License as 
   published by the Free Software Foundation; either version 2 of the 
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   The FPC Documentation is distributed in the hope that it will be useful, 
   but WITHOUT ANY WARRANTY; without even the implied warranty of 
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
   Library General Public License for more details. 
 
   You should have received a copy of the GNU Library General Public 
   License along with the FPC documentation; see the file COPYING.LIB.  If not, 
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, 
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 -->
<package name="rtl">
<module name="ports">
<short>Access to hardware ports</short>
<descr>
<p>
The ports unit implements the <var>port</var> constructs found in Turbo Pascal. 
It uses classes and default array properties to do this.
</p>
<p>
The unit exists on linux, os/2 and dos. It is implemented only for
compatibility with Turbo Pascal. It's usage is discouraged, because using ports
is not portable programming, and the operating system may not even allow
it (for instance Windows).
</p>
<p>
Under linux, your program must be run as root, or the <var>IOPerm</var> call
must be set in order to set appropriate permissions on the port access.
</p>
</descr>

<element name="TPort">
<short>Type implemented to support integer-sized port access</short>
<descr>
The <var>TPort</var> type is implemented specially for access to the ports
in a TP compatible manner. There is no need to create an instance of this
type: the standard TP variables are instantiated at unit initialization.
</descr>
<seealso>
<link id="port"/>
<link id="TPortW"/>
<link id="TPortL"/>
</seealso>
</element>

<element name="tport.writeport">
<short>Writes an integer of data to a port</short>
<descr>
</descr>
<seealso>
<link id="tport.readport"/>
</seealso>
</element>

<element name="tport.readport">
<short>Reads an integer of data from a port</short>
<descr>
</descr>
<seealso>
<link id="tport.writeport"/>
</seealso>
</element>

<element name="tport.pp">
<short>Access integer-sized port by port number</short>
<descr>
</descr>
</element>

<element name="TPortW">
<short>Type implemented to support word-sized port access</short>
<descr>
The <var>TPortW</var> type is implemented specially for access to the ports
in a TP compatible manner. There is no need to create an instance of this
type: the standard TP variables are instantiated at unit initialization.
</descr>
<seealso>
<link id="portw"/>
<link id="TPort"/>
<link id="TPortL"/>
</seealso>
</element>

<element name="TPortW.writeport">
<short>Writes a word of data to a port</short>
<descr>
</descr>
<seealso>
<link id="TPortW.readport"/>
</seealso>
</element>

<element name="TPortW.readport">
<short>Reads a word of data from a port</short>
<descr>
</descr>
<seealso>
<link id="TPortW.writeport"/>
</seealso>
</element>

<element name="TPortW.pp">
<short>Access word-sized port by port number</short>
<descr>
</descr>
</element>

<element name="TPortL">
<short>Type implemented to support Longint-sized port access</short>
<descr>
The <var>TPortL</var> type is implemented specially for access to the ports
in a TP compatible manner. There is no need to create an instance of this
type: the standard TP variables are instantiated at unit initialization.
</descr>
<seealso>
<link id="portw"/>
<link id="TPort"/>
<link id="TPortL"/>
</seealso>
</element>

<element name="TPortL.writeport">
<short>Writes a Longint of data to a port</short>
<descr>
</descr>
<seealso>
<link id="TPortL.readport"/>
</seealso>
</element>

<element name="TPortL.readport">
<short>Reads a Longint of data from a port</short>
<descr>
</descr>
<seealso>
<link id="TPortL.writeport"/>
</seealso>
</element>

<element name="TPortL.pp">
<short>Access Longint-sized port by port number</short>
<descr>
</descr>
</element>

<element name="Port">
<short>Provide port access per integer</short>
<descr>
<p>
Default instance of type <link id="TPort"/>. Do not free. This variable is
initialized in the unit initialization code, and freed at finalization.
</p>
<p>
Since there is a default property for a variable of this type, a sentence as
</p>
<code>
  port[221]:=12;
</code>
<p>
Will result in the integer 12 being written to port 221, if port is defined
as a variable of type <var>tport</var>
</p>
</descr>
</element>

<element name="Portb">
<short>Provide port access per byte</short>
<descr>
<p>
Default instance of type <link id="TPort"/>. Do not free. This variable is
initialized in the unit initialization code, and freed at finalization.
</p>
<p>
Since there is a default property for a variable of this type, a sentence as
</p>
<code>
  portb[221]:=12;
</code>
<p>
Will result in the byte 12 being written to port 221, if port is defined
as a variable of type <var>tport</var>
</p>
</descr>
</element>

<element name="PortW">
<short>Provide port access per word</short>
<descr>
<p>
Default instance of type <link id="TPortW"/>. Do not free. This variable is
initialized in the unit initialization code, and freed at finalization.
</p>
<p>
Since there is a default property for a variable of this type, a sentence as
</p>
<code>
  portb[221]:=12;
</code>
<p>
Will result in the word 12 being written to port 221, if port is defined
as a variable of type <var>tport</var>
</p>
</descr>
</element>

<element name="PortL">
<short>Provide port access per longint</short>
<descr>
<p>
Default instance of type <link id="TPortL"/>. Do not free. This variable is
initialized in the unit initialization code, and freed at finalization.
</p>
<p>
Since there is a default property for a variable of this type, a sentence as
</p>
<code>
  portl[221]:=12;
</code>
<p>
Will result in the longint 12 being written to port 221, if port is defined
as a variable of type <var>tport</var>
</p>
</descr>
</element>

</module>
</package>
</fpdoc-descriptions>
