📄 ref.no-define.html

📁 有关ecos2。0介绍了实时嵌入式的结构以及线程调度的实现和内存的管理等
💻 HTML
字号:
<!-- 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"><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+"><LINKREL="HOME"TITLE="The eCos Component Writer's Guide"HREF="cdl-guide.html"><LINKREL="UP"TITLE="CDL Language Specification"HREF="reference.html"><LINKREL="PREVIOUS"TITLE="make_object"HREF="ref.make-object.html"><LINKREL="NEXT"TITLE="parent"HREF="ref.parent.html"></HEAD><BODYCLASS="REFENTRY"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">The <SPANCLASS="APPLICATION">eCos</SPAN> Component Writer's Guide</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="ref.make-object.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom"></TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="ref.parent.html"ACCESSKEY="N">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><H1><ANAME="REF.NO-DEFINE"><SPANCLASS="PROPERTY">no_define</SPAN></H1><DIVCLASS="REFNAMEDIV"><ANAME="AEN4836"></A><H2>Name</H2>Property <SPANCLASS="PROPERTY">no_define</SPAN>&nbsp;--&nbsp;Suppress the normal generation of a preprocessor<TTCLASS="LITERAL">#define</TT> symbol in a configuration header file.</DIV><DIVCLASS="REFSYNOPSISDIV"><ANAME="AEN4841"><H2>Synopsis</H2><TABLEBORDER="5"BGCOLOR="#E0E0F0"WIDTH="70%"><TR><TD><PRECLASS="SYNOPSIS">cdl_option &lt;name&gt; {    no_define    &#8230;}</PRE></TD></TR></TABLE></DIV><DIVCLASS="REFSECT1"><ANAME="AEN4843"></A><H2>Description</H2><P>By default all active and enabled properties result in either one ortwo <TTCLASS="LITERAL">#define'd</TT> symbols in the package'sconfiguration header file, and this is one of the main ways in whichoptions can affect packages at build-time. It is possible to suppressthe default <TTCLASS="LITERAL">#define's</TT> by specifying a<SPANCLASS="PROPERTY">no_define</SPAN> property in the body of an option or other <SPANCLASS="APPLICATION">CDL</SPAN> entity. This property takes no arguments and should occur only once in a givenbody. </P><P>The <SPANCLASS="PROPERTY">no_define</SPAN> property is frequently used in conjunction with one ofthe other header-file related properties such as <SPANCLASS="PROPERTY">define</SPAN>. If one ofthe other properties is used to export the required information to aconfiguration header file then often there is little point inexporting the default <TTCLASS="LITERAL">#define</TT> aswell&nbsp;&#8212;&nbsp; in fact there could be a name clash. The<SPANCLASS="PROPERTY">no_define</SPAN> property can also be useful if the sole purpose of anoption is to affect which files get built, and the default<TTCLASS="LITERAL">#define</TT> would never get tested in any source code.However in such cases the default <TTCLASS="LITERAL">#define</TT> ismostly harmless and there is little to be gained by suppressing it.</P></DIV><DIVCLASS="REFSECT1"><ANAME="AEN4857"></A><H2>Example</H2><TABLEBORDER="5"BGCOLOR="#E0E0F0"WIDTH="70%"><TR><TD><PRECLASS="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    &#8230;}</PRE></TD></TR></TABLE></DIV><DIVCLASS="REFSECT1"><ANAME="AEN4860"></A><H2>See Also</H2><P>Properties <AHREF="ref.define.html"><SPANCLASS="PROPERTY">define</SPAN></A>,<AHREF="ref.define-format.html"><SPANCLASS="PROPERTY">define_format</SPAN></A>,<AHREF="ref.define-header.html"><SPANCLASS="PROPERTY">define_header</SPAN></A>,<AHREF="ref.define-proc.html"><SPANCLASS="PROPERTY">define_proc</SPAN></A> and<AHREF="ref.if-define.html"><SPANCLASS="PROPERTY">if_define</SPAN></A>.</P></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="ref.make-object.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="cdl-guide.html"ACCESSKEY="H">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="ref.parent.html"ACCESSKEY="N">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><SPANCLASS="PROPERTY">make_object</SPAN></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="reference.html"ACCESSKEY="U">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><SPANCLASS="PROPERTY">parent</SPAN></TD></TR></TABLE></DIV></BODY></HTML>
⌨️ 快捷键说明

复制代码 Ctrl + C
搜索代码 Ctrl + F
全屏模式 F11
切换主题 Ctrl + Shift + D
显示快捷键 ?
增大字号 Ctrl + =
减小字号 Ctrl + -