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<!-- 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 >no_define</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="make_object" HREF="ref.make-object.html"><LINK REL="NEXT" TITLE="parent" HREF="ref.parent.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.make-object.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="ref.parent.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="REF.NO-DEFINE"><SPAN CLASS="PROPERTY" >no_define</SPAN ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN4836" ></A ><H2 >Name</H2 >Property <SPAN CLASS="PROPERTY" >no_define</SPAN > -- Suppress the normal generation of a preprocessor <TT CLASS="LITERAL" >#define</TT > symbol in a configuration header file.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN4841"><H2 >Synopsis</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="SYNOPSIS" >cdl_option <name> { no_define … }</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4843" ></A ><H2 >Description</H2 ><P >By default all active and enabled properties result in either one or two <TT CLASS="LITERAL" >#define'd</TT > symbols in the package's configuration header file, and this is one of the main ways in which options can affect packages at build-time. It is possible to suppress the default <TT CLASS="LITERAL" >#define's</TT > by specifying a <SPAN CLASS="PROPERTY" >no_define</SPAN > property in the body of an option or other <SPAN CLASS="APPLICATION" >CDL</SPAN > entity. This property takes no arguments and should occur only once in a given body. </P ><P >The <SPAN CLASS="PROPERTY" >no_define</SPAN > property is frequently used in conjunction with one of the other header-file related properties such as <SPAN CLASS="PROPERTY" >define</SPAN >. If one of the other properties is used to export the required information to a configuration header file then often there is little point in exporting the default <TT CLASS="LITERAL" >#define</TT > as well — in fact there could be a name clash. The <SPAN CLASS="PROPERTY" >no_define</SPAN > property can also be useful if the sole purpose of an option is to affect which files get built, and the default <TT CLASS="LITERAL" >#define</TT > would never get tested in any source code. However in such cases the default <TT CLASS="LITERAL" >#define</TT > is mostly harmless and there is little to be gained by suppressing it.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4857" ></A ><H2 >Example</H2 ><TABLE BORDER="5" BGCOLOR="#E0E0F0" WIDTH="70%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" >cdl_component CYG_HAL_STARTUP { display "Startup type" flavor data legal_values { "RAM" "ROM" } default_value {"RAM"} no_define define -file system.h CYG_HAL_STARTUP … }</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4860" ></A ><H2 >See Also</H2 ><P >Properties <A HREF="ref.define.html" ><SPAN CLASS="PROPERTY" >define</SPAN ></A >, <A HREF="ref.define-format.html" ><SPAN CLASS="PROPERTY" >define_format</SPAN ></A >, <A HREF="ref.define-header.html" ><SPAN CLASS="PROPERTY" >define_header</SPAN ></A >, <A HREF="ref.define-proc.html" ><SPAN CLASS="PROPERTY" >define_proc</SPAN ></A > and <A HREF="ref.if-define.html" ><SPAN CLASS="PROPERTY" >if_define</SPAN ></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.make-object.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.parent.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><SPAN CLASS="PROPERTY" >make_object</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" >parent</SPAN ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >
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