URL
https://opencores.org/ocsvn/openrisc/openrisc/trunk
Subversion Repositories openrisc
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [cdl-guide/] [ref.define-format.html] - Rev 598
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
>define_format</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="define"
HREF="ref.define.html"><LINK
REL="NEXT"
TITLE="define_header"
HREF="ref.define-header.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.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.define-header.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="REF.DEFINE-FORMAT"><SPAN
CLASS="PROPERTY"
>define_format</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4073"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>define_format</SPAN
> -- Control how an option's value will appear in the
configuration header file.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4077"><H2
>Synopsis</H2
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="SYNOPSIS"
>cdl_option <name> {
define_format <format string>
…
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4079"
></A
><H2
>Description</H2
><P
>For active options with the <TT
CLASS="LITERAL"
>data</TT
> flavor, and for
active and enabled options with the <TT
CLASS="LITERAL"
>booldata</TT
>
flavor, the configuration tools will normally generate two
<TT
CLASS="LITERAL"
>#define's</TT
> in the package's configuration header
file. These take the following forms:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>#define <name> <value>
#define <name>_<value></PRE
></TD
></TR
></TABLE
><P
>The <SPAN
CLASS="PROPERTY"
>define_format</SPAN
> property can be used to control exactly what
appears as the value for the first of these
<TT
CLASS="LITERAL"
>#define's</TT
>. For example, the following can be used
to output some configuration data as a C string:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_option <name> {
…
define -format="\\\"%s\\\"" <symbol>
}</PRE
></TD
></TR
></TABLE
><P
>The implementation of <SPAN
CLASS="PROPERTY"
>define_format</SPAN
> involves concatenating the Tcl
command <TT
CLASS="LITERAL"
>format</TT
>, the format string, and the string
representation of the option's value, and evaluating this in a Tcl
interpreter. Therefore the format string will be processed twice by a
Tcl parser, and appropriate care has to be taken with quoting.</P
><P
>The second <TT
CLASS="LITERAL"
>#define</TT
> will be generated only if is a
valid C preprocessor macro symbol, and is not affected by the
<SPAN
CLASS="PROPERTY"
>define_format</SPAN
> property. Also, the property is only relevant for
options with the <TT
CLASS="LITERAL"
>data</TT
> or
<TT
CLASS="LITERAL"
>booldata</TT
> flavor, and cannot be used in
conjunction with the <SPAN
CLASS="PROPERTY"
>no_define</SPAN
> property since it makes no sense to
specify the format if no <TT
CLASS="LITERAL"
>#define</TT
> is generated.</P
><DIV
CLASS="CAUTION"
><P
></P
><TABLE
CLASS="CAUTION"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>Caution</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
>Because the Tcl interpreter's <TT
CLASS="LITERAL"
>format</TT
> command is
used, this property is subject to any problems with the implementation
of this in the Tcl library. Generally there should be no problems with
string data or with integers up to 32 bits, but there may well be
problems if 64-bit data is involved. This issue may be addressed in a
future release.</P
></TD
></TR
></TABLE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4103"
></A
><H2
>Example</H2
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_option CYGNUM_UITRON_VER_ID {
display "OS identification"
flavor data
legal_values 0 to 0xFFFF
default_value 0
define_format "0x%04x"
description "
This value is returned in the 'id'
field of the T_VER structure in
response to a get_ver() system call."
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4106"
></A
><H2
>See Also</H2
><P
>Properties <A
HREF="ref.define.html"
><SPAN
CLASS="PROPERTY"
>define</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
>,
<A
HREF="ref.if-define.html"
><SPAN
CLASS="PROPERTY"
>if_define</SPAN
></A
> and
<A
HREF="ref.no-define.html"
><SPAN
CLASS="PROPERTY"
>no_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.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.define-header.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><SPAN
CLASS="PROPERTY"
>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"
>define_header</SPAN
></TD
></TR
></TABLE
></DIV
></BODY
></HTML
> Go to most recent revision | Compare with Previous | Blame | View Log