URL
https://opencores.org/ocsvn/openrisc/openrisc/trunk
Subversion Repositories openrisc
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [cdl-guide/] [ref.implements.html] - Rev 593
Go to most recent revision | Compare with Previous | Blame | View Log
<!-- Copyright (C) 2003 Red Hat, Inc. --> <!-- This material may be distributed only subject to the terms --> <!-- and conditions set forth in the Open Publication License, v1.0 --> <!-- or later (the latest version is presently available at --> <!-- http://www.opencontent.org/openpub/). --> <!-- Distribution of the work or derivative of the work in any --> <!-- standard (paper) book form is prohibited unless prior --> <!-- permission is obtained from the copyright holder. --> <HTML ><HEAD ><TITLE >implements</TITLE ><meta name="MSSmartTagsPreventParsing" content="TRUE"> <META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="The eCos Component Writer's Guide" HREF="cdl-guide.html"><LINK REL="UP" TITLE="CDL Language Specification" HREF="reference.html"><LINK REL="PREVIOUS" TITLE="if_define" HREF="ref.if-define.html"><LINK REL="NEXT" TITLE="include_dir" HREF="ref.include-dir.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >The <SPAN CLASS="APPLICATION" >eCos</SPAN > Component Writer's Guide</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="ref.if-define.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="ref.include-dir.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="REF.IMPLEMENTS"><SPAN CLASS="PROPERTY" >implements</SPAN ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN4507" ></A ><H2 >Name</H2 >Property <SPAN CLASS="PROPERTY" >implements</SPAN > -- Enabling this option provides one instance of a more general interface.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN4511"><H2 >Synopsis</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="SYNOPSIS" >cdl_option <name> { implements <interface> … }</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4513" ></A ><H2 >Description</H2 ><P >The <SPAN CLASS="APPLICATION" >CDL</SPAN > interface concept provides an abstraction mechanism that can be useful in many different circumstances. Essentially an interface is a calculated option whose value is the number of active and enabled options which implement that interface. For example the interface <TT CLASS="VARNAME" >CYGINT_KERNEL_SCHEDULER</TT > has a value corresponding to the number of schedulers in the system, typically just one.</P ><P >The <SPAN CLASS="PROPERTY" >implements</SPAN > property takes a single argument, which should be the name of an interface. This interface may be defined in the same package as the implementor or in some other package. In the latter case it may sometimes be appropriate for the implementor or the implementor's package to have a <SPAN CLASS="PROPERTY" >requires</SPAN > property for the package containing the interface. An option may contain multiple <SPAN CLASS="PROPERTY" >implements</SPAN > properties. It is possible for an option to implement a given interface multiple times, and on occasion this is actually useful.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4522" ></A ><H2 >Example</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" >cdl_option CYGSEM_KERNEL_SCHED_MLQUEUE { display "Multi-level queue scheduler" default_value 1 implements CYGINT_KERNEL_SCHEDULER … }</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4525" ></A ><H2 >See Also</H2 ><P >Command <A HREF="ref.cdl-interface.html" ><TT CLASS="LITERAL" >cdl_interface</TT ></A >.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="ref.if-define.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdl-guide.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="ref.include-dir.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><SPAN CLASS="PROPERTY" >if_define</SPAN ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="reference.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><SPAN CLASS="PROPERTY" >include_dir</SPAN ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >
Go to most recent revision | Compare with Previous | Blame | View Log