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<!-- Copyright (C) 2003 Red Hat, Inc.                                -->
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<!-- 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       -->
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<HTML
><HEAD
><TITLE
>legal_values</TITLE
><meta name="MSSmartTagsPreventParsing" content="TRUE">
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><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="REF.LEGAL-VALUES"><SPAN
CLASS="PROPERTY"
>legal_values</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4615"
></A
><H2
>Name</H2
>Property <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
>&nbsp;--&nbsp;Impose constraints on the possible values for an option.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN4619"><H2
>Synopsis</H2
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="SYNOPSIS"
>cdl_option &lt;name&gt; {
    legal_values &lt;list expression&gt;
    &#8230;
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4621"
></A
><H2
>Description</H2
><P
>Options with the <TT
CLASS="LITERAL"
>data</TT
> or
<TT
CLASS="LITERAL"
>booldata</TT
> flavors can have an arbitrary sequence of
characters as their data. In nearly all cases some restrictions have
to be imposed, for example the data should correspond to a number
within a certain range, or it should be one of a small number of
constants. The <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> property can be used to impose such
constraints. The arguments to the property should be a <SPAN
CLASS="APPLICATION"
>CDL</SPAN
> list
expression, see <A
HREF="language.values.html#LANGUAGE.LIST-EXPRESSION"
>the Section called <I
>List Expressions</I
> in Chapter 3</A
> for the
syntactic details. Common examples include:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>    legal_values 0 to 0x7fff
    legal_values 9600 19200 38400
    legal_values { "RAM" "ROM" }</PRE
></TD
></TR
></TABLE
><P
>The <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> property can only be used for options with the
<TT
CLASS="LITERAL"
>data</TT
> or <TT
CLASS="LITERAL"
>booldata</TT
> flavors, since
it makes little sense to further constrain the legal values of a
boolean option. An option can have at most one <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
>
property.</P
><DIV
CLASS="TIP"
><BLOCKQUOTE
CLASS="TIP"
><P
><B
>Tip: </B
>If the first entry in a <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> list expression is a negative
number, for example
<TT
CLASS="LITERAL"
>legal_values&nbsp;-1&nbsp;to&nbsp;1</TT
>  then this can
be misinterpreted as an option instead of as part of the expression.
Currently the <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> property does not take any options, but
this may change in future. Option processing halts at the sequence
<TT
CLASS="LITERAL"
>--</TT
>, so the desired range can be expressed safely
using <TT
CLASS="LITERAL"
>legal_values&nbsp;--&nbsp;-1&nbsp;to&nbsp;1</TT
></P
></BLOCKQUOTE
></DIV
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>Architectural HAL packages should provide constants which can be used
in <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> list expressions. For example it should be possible
to specify a numeric range such as
<TT
CLASS="LITERAL"
>0&nbsp;to&nbsp;CYGARC_MAXINT</TT
>, rather than
hard-wiring numbers such as <TT
CLASS="LITERAL"
>0x7fffffff</TT
> which may
not be valid on all targets. Current HAL packages do not define such
constants. </P
></BLOCKQUOTE
></DIV
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>The <SPAN
CLASS="PROPERTY"
>legal_values</SPAN
> property is restricted mainly to numerical ranges
and simple enumerations, and cannot cope with more complicated data
items. Future versions of the configuration system will provide
additional data validation facilities, for example a
<TT
CLASS="LITERAL"
>check_proc</TT
> property which specifies a Tcl script
that can be used to perform the validation.</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4651"
></A
><H2
>Example</H2
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_option CYGNUM_LIBC_TIME_STD_DEFAULT_OFFSET {
    display       "Default Standard Time offset"
    flavor        data
    legal_values  -- -90000 to 90000
    default_value -- 0
    description   "
        This option controls the offset from UTC in
        seconds when in local Standard Time. This
        value can be positive or negative. It
        can also be set at run time using the
        cyg_libc_time_setzoneoffsets() function."
}</PRE
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4654"
></A
><H2
>See Also</H2
><P
>Properties <A
HREF="ref.calculated.html"
><SPAN
CLASS="PROPERTY"
>calculated</SPAN
></A
>,
<A
HREF="ref.default-value.html"
><SPAN
CLASS="PROPERTY"
>default_value</SPAN
></A
>, and
<A
HREF="ref.flavor.html"
><SPAN
CLASS="PROPERTY"
>flavor</SPAN
></A
>.</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
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><TR
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ALIGN="left"
VALIGN="top"
><A
HREF="ref.include-files.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.library.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><SPAN
CLASS="PROPERTY"
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VALIGN="top"
><A
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ACCESSKEY="U"
>Up</A
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><SPAN
CLASS="PROPERTY"
>library</SPAN
></TD
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></DIV
></BODY
></HTML
>

Line No.	Rev	Author	Line
1	28	unneback	`<!-- Copyright (C) 2003 Red Hat, Inc. -->`
2			`<!-- This material may be distributed only subject to the terms -->`
3			`<!-- and conditions set forth in the Open Publication License, v1.0 -->`
4			`<!-- or later (the latest version is presently available at -->`
5			`<!-- http://www.opencontent.org/openpub/). -->`
6			`<!-- Distribution of the work or derivative of the work in any -->`
7			`<!-- standard (paper) book form is prohibited unless prior -->`
8			`<!-- permission is obtained from the copyright holder. -->`
9			`<HTML`
10			`><HEAD`
11			`><TITLE`
12			`>legal_values</TITLE`
13			`><meta name="MSSmartTagsPreventParsing" content="TRUE">`
14			`<META`
15			`NAME="GENERATOR"`
16			`CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+`
17			`"><LINK`
18			`REL="HOME"`
19			`TITLE="The eCos Component Writer's Guide"`
20			`HREF="cdl-guide.html"><LINK`
21			`REL="UP"`
22			`TITLE="CDL Language Specification"`
23			`HREF="reference.html"><LINK`
24			`REL="PREVIOUS"`
25			`TITLE="include_files"`
26			`HREF="ref.include-files.html"><LINK`
27			`REL="NEXT"`
28			`TITLE="library"`
29			`HREF="ref.library.html"></HEAD`
30			`><BODY`
31			`CLASS="REFENTRY"`
32			`BGCOLOR="#FFFFFF"`
33			`TEXT="#000000"`
34			`LINK="#0000FF"`
35			`VLINK="#840084"`
36			`ALINK="#0000FF"`
37			`><DIV`
38			`CLASS="NAVHEADER"`
39			`><TABLE`
40			`SUMMARY="Header navigation table"`
41			`WIDTH="100%"`
42			`BORDER="0"`
43			`CELLPADDING="0"`
44			`CELLSPACING="0"`
45			`><TR`
46			`><TH`
47			`COLSPAN="3"`
48			`ALIGN="center"`
49			`>The <SPAN`
50			`CLASS="APPLICATION"`
51			`>eCos</SPAN`
52			`> Component Writer's Guide</TH`
53			`></TR`
54			`><TR`
55			`><TD`
56			`WIDTH="10%"`
57			`ALIGN="left"`
58			`VALIGN="bottom"`
59			`><A`
60			`HREF="ref.include-files.html"`
61			`ACCESSKEY="P"`
62			`>Prev</A`
63			`></TD`
64			`><TD`
65			`WIDTH="80%"`
66			`ALIGN="center"`
67			`VALIGN="bottom"`
68			`></TD`
69			`><TD`
70			`WIDTH="10%"`
71			`ALIGN="right"`
72			`VALIGN="bottom"`
73			`><A`
74			`HREF="ref.library.html"`
75			`ACCESSKEY="N"`
76			`>Next</A`
77			`></TD`
78			`></TR`
79			`></TABLE`
80			`><HR`
81			`ALIGN="LEFT"`
82			`WIDTH="100%"></DIV`
83			`><H1`
84			`><A`
85			`NAME="REF.LEGAL-VALUES"><SPAN`
86			`CLASS="PROPERTY"`
87			`>legal_values</SPAN`
88			`></H1`
89			`><DIV`
90			`CLASS="REFNAMEDIV"`
91			`><A`
92			`NAME="AEN4615"`
93			`></A`
94			`><H2`
95			`>Name</H2`
96			`>Property <SPAN`
97			`CLASS="PROPERTY"`
98			`>legal_values</SPAN`
99			`> -- Impose constraints on the possible values for an option.</DIV`
100			`><DIV`
101			`CLASS="REFSYNOPSISDIV"`
102			`><A`
103			`NAME="AEN4619"><H2`
104			`>Synopsis</H2`
105			`><TABLE`
106			`BORDER="5"`
107			`BGCOLOR="#E0E0F0"`
108			`WIDTH="70%"`
109			`><TR`
110			`><TD`
111			`><PRE`
112			`CLASS="SYNOPSIS"`
113			`>cdl_option <name> {`
114			`legal_values <list expression>`
115			`…`
116			`}</PRE`
117			`></TD`
118			`></TR`
119			`></TABLE`
120			`></DIV`
121			`><DIV`
122			`CLASS="REFSECT1"`
123			`><A`
124			`NAME="AEN4621"`
125			`></A`
126			`><H2`
127			`>Description</H2`
128			`><P`
129			`>Options with the <TT`
130			`CLASS="LITERAL"`
131			`>data</TT`
132			`> or`
133			`<TT`
134			`CLASS="LITERAL"`
135			`>booldata</TT`
136			`> flavors can have an arbitrary sequence of`
137			`characters as their data. In nearly all cases some restrictions have`
138			`to be imposed, for example the data should correspond to a number`
139			`within a certain range, or it should be one of a small number of`
140			`constants. The <SPAN`
141			`CLASS="PROPERTY"`
142			`>legal_values</SPAN`
143			`> property can be used to impose such`
144			`constraints. The arguments to the property should be a <SPAN`
145			`CLASS="APPLICATION"`
146			`>CDL</SPAN`
147			`> list`
148			`expression, see <A`
149			`HREF="language.values.html#LANGUAGE.LIST-EXPRESSION"`
150			`>the Section called <I`
151			`>List Expressions</I`
152			`> in Chapter 3</A`
153			`> for the`
154			`syntactic details. Common examples include:</P`
155			`><TABLE`
156			`BORDER="5"`
157			`BGCOLOR="#E0E0F0"`
158			`WIDTH="70%"`
159			`><TR`
160			`><TD`
161			`><PRE`
162			`CLASS="PROGRAMLISTING"`
163			`> legal_values 0 to 0x7fff`
164			`legal_values 9600 19200 38400`
165			`legal_values { "RAM" "ROM" }</PRE`
166			`></TD`
167			`></TR`
168			`></TABLE`
169			`><P`
170			`>The <SPAN`
171			`CLASS="PROPERTY"`
172			`>legal_values</SPAN`
173			`> property can only be used for options with the`
174			`<TT`
175			`CLASS="LITERAL"`
176			`>data</TT`
177			`> or <TT`
178			`CLASS="LITERAL"`
179			`>booldata</TT`
180			`> flavors, since`
181			`it makes little sense to further constrain the legal values of a`
182			`boolean option. An option can have at most one <SPAN`
183			`CLASS="PROPERTY"`
184			`>legal_values</SPAN`
185			`>`
186			`property.</P`
187			`><DIV`
188			`CLASS="TIP"`
189			`><BLOCKQUOTE`
190			`CLASS="TIP"`
191			`><P`
192			`><B`
193			`>Tip: </B`
194			`>If the first entry in a <SPAN`
195			`CLASS="PROPERTY"`
196			`>legal_values</SPAN`
197			`> list expression is a negative`
198			`number, for example`
199			`<TT`
200			`CLASS="LITERAL"`
201			`>legal_values -1 to 1</TT`
202			`> then this can`
203			`be misinterpreted as an option instead of as part of the expression.`
204			`Currently the <SPAN`
205			`CLASS="PROPERTY"`
206			`>legal_values</SPAN`
207			`> property does not take any options, but`
208			`this may change in future. Option processing halts at the sequence`
209			`<TT`
210			`CLASS="LITERAL"`
211			`>--</TT`
212			`>, so the desired range can be expressed safely`
213			`using <TT`
214			`CLASS="LITERAL"`
215			`>legal_values -- -1 to 1</TT`
216			`></P`
217			`></BLOCKQUOTE`
218			`></DIV`
219			`><DIV`
220			`CLASS="NOTE"`
221			`><BLOCKQUOTE`
222			`CLASS="NOTE"`
223			`><P`
224			`><B`
225			`>Note: </B`
226			`>Architectural HAL packages should provide constants which can be used`
227			`in <SPAN`
228			`CLASS="PROPERTY"`
229			`>legal_values</SPAN`
230			`> list expressions. For example it should be possible`
231			`to specify a numeric range such as`
232			`<TT`
233			`CLASS="LITERAL"`
234			`>0 to CYGARC_MAXINT</TT`
235			`>, rather than`
236			`hard-wiring numbers such as <TT`
237			`CLASS="LITERAL"`
238			`>0x7fffffff</TT`
239			`> which may`
240			`not be valid on all targets. Current HAL packages do not define such`
241			`constants. </P`
242			`></BLOCKQUOTE`
243			`></DIV`
244			`><DIV`
245			`CLASS="NOTE"`
246			`><BLOCKQUOTE`
247			`CLASS="NOTE"`
248			`><P`
249			`><B`
250			`>Note: </B`
251			`>The <SPAN`
252			`CLASS="PROPERTY"`
253			`>legal_values</SPAN`
254			`> property is restricted mainly to numerical ranges`
255			`and simple enumerations, and cannot cope with more complicated data`
256			`items. Future versions of the configuration system will provide`
257			`additional data validation facilities, for example a`
258			`<TT`
259			`CLASS="LITERAL"`
260			`>check_proc</TT`
261			`> property which specifies a Tcl script`
262			`that can be used to perform the validation.</P`
263			`></BLOCKQUOTE`
264			`></DIV`
265			`></DIV`
266			`><DIV`
267			`CLASS="REFSECT1"`
268			`><A`
269			`NAME="AEN4651"`
270			`></A`
271			`><H2`
272			`>Example</H2`
273			`><TABLE`
274			`BORDER="5"`
275			`BGCOLOR="#E0E0F0"`
276			`WIDTH="70%"`
277			`><TR`
278			`><TD`
279			`><PRE`
280			`CLASS="PROGRAMLISTING"`
281			`>cdl_option CYGNUM_LIBC_TIME_STD_DEFAULT_OFFSET {`
282			`display "Default Standard Time offset"`
283			`flavor data`
284			`legal_values -- -90000 to 90000`
285			`default_value -- 0`
286			`description "`
287			`This option controls the offset from UTC in`
288			`seconds when in local Standard Time. This`
289			`value can be positive or negative. It`
290			`can also be set at run time using the`
291			`cyg_libc_time_setzoneoffsets() function."`
292			`}</PRE`
293			`></TD`
294			`></TR`
295			`></TABLE`
296			`></DIV`
297			`><DIV`
298			`CLASS="REFSECT1"`
299			`><A`
300			`NAME="AEN4654"`
301			`></A`
302			`><H2`
303			`>See Also</H2`
304			`><P`
305			`>Properties <A`
306			`HREF="ref.calculated.html"`
307			`><SPAN`
308			`CLASS="PROPERTY"`
309			`>calculated</SPAN`
310			`></A`
311			`>,`
312			`<A`
313			`HREF="ref.default-value.html"`
314			`><SPAN`
315			`CLASS="PROPERTY"`
316			`>default_value</SPAN`
317			`></A`
318			`>, and`
319			`<A`
320			`HREF="ref.flavor.html"`
321			`><SPAN`
322			`CLASS="PROPERTY"`
323			`>flavor</SPAN`
324			`></A`
325			`>.</P`
326			`></DIV`
327			`><DIV`
328			`CLASS="NAVFOOTER"`
329			`><HR`
330			`ALIGN="LEFT"`
331			`WIDTH="100%"><TABLE`
332			`SUMMARY="Footer navigation table"`
333			`WIDTH="100%"`
334			`BORDER="0"`
335			`CELLPADDING="0"`
336			`CELLSPACING="0"`
337			`><TR`
338			`><TD`
339			`WIDTH="33%"`
340			`ALIGN="left"`
341			`VALIGN="top"`
342			`><A`
343			`HREF="ref.include-files.html"`
344			`ACCESSKEY="P"`
345			`>Prev</A`
346			`></TD`
347			`><TD`
348			`WIDTH="34%"`
349			`ALIGN="center"`
350			`VALIGN="top"`
351			`><A`
352			`HREF="cdl-guide.html"`
353			`ACCESSKEY="H"`
354			`>Home</A`
355			`></TD`
356			`><TD`
357			`WIDTH="33%"`
358			`ALIGN="right"`
359			`VALIGN="top"`
360			`><A`
361			`HREF="ref.library.html"`
362			`ACCESSKEY="N"`
363			`>Next</A`
364			`></TD`
365			`></TR`
366			`><TR`
367			`><TD`
368			`WIDTH="33%"`
369			`ALIGN="left"`
370			`VALIGN="top"`
371			`><SPAN`
372			`CLASS="PROPERTY"`
373			`>include_files</SPAN`
374			`></TD`
375			`><TD`
376			`WIDTH="34%"`
377			`ALIGN="center"`
378			`VALIGN="top"`
379			`><A`
380			`HREF="reference.html"`
381			`ACCESSKEY="U"`
382			`>Up</A`
383			`></TD`
384			`><TD`
385			`WIDTH="33%"`
386			`ALIGN="right"`
387			`VALIGN="top"`
388			`><SPAN`
389			`CLASS="PROPERTY"`
390			`>library</SPAN`
391			`></TD`
392			`></TR`
393			`></TABLE`
394			`></DIV`
395			`></BODY`
396			`></HTML`
397			`>`

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[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [cdl-guide/] [ref.legal-values.html] - Blame information for rev 579