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manual.docbook: add <strz/> and <const/>

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Daniel Marjamäki 2016-07-30 16:23:03 +02:00
parent c985c39018
commit 63540bc114
1 changed files with 47 additions and 13 deletions
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man/manual.docbook
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@ -695,6 +695,10 @@ Checking test.c...
configuration files. It is available in the <literal>View</literal>
menu. All settings are not documented in this manual.</para>
<para>If you have a question about the <literal>.cfg</literal> file
format it is recommended you ask in the forum
(http://sourceforge.net/p/cppcheck/discussion/).</para>
<para>The command line cppcheck will try to load custom .cfg files from
the working path - execute cppcheck from the path where the .cfg files
are.</para>
@ -1118,6 +1122,23 @@ Checking minsize.c...
</varlistentry>
</variablelist>
</section>
<section>
<title>strz</title>
<para>This setting is not used by Cppcheck currently. But with this
you can say that an argument must be a zero-terminated
string.</para>
<para><programlisting>&lt;?xml version="1.0"?&gt;
&lt;def&gt;
&lt;function name="do_something"&gt;
&lt;arg nr="1"&gt;
&lt;strz/&gt;
&lt;/arg&gt;
&lt;/function&gt;
&lt;/def&gt;</programlisting></para>
</section>
</section>
<section>
@ -1209,11 +1230,19 @@ Checking useretval.c...
</section>
<section>
<title>pure</title>
<title>pure and const</title>
<para>A function that is pure will calculate a return value and has no
side effects. If the same parameters are given twice then the same
return value will be calculated twice.</para>
<para>These correspond to the GCC function attributes pure and
const.</para>
<para>A pure function has no effects except to return a value, and its
return value depends only on the parameters and global
variables.</para>
<para>A const function has no effects except to return a value, and
its return value depends only on the parameters.</para>
<para>Here is an example code:</para>
<programlisting>void f(int x)
{
@ -1224,24 +1253,29 @@ Checking useretval.c...
}
}</programlisting>
<para>Cppcheck reports no warning</para>
<para>If <literal>calculate()</literal> is a const function then the
result of <literal>calculate(x)</literal> will be the same in both
conditions, since the same parameter value is used.</para>
<programlisting># cppcheck pure.c
Checking pure.c...</programlisting>
<para>Cppcheck normally assumes that the result might be different,
and reports no warning for the code:</para>
<para>If a proper <literal>lib.cfg</literal> is provided, the
<programlisting># cppcheck const.c
Checking const.c...</programlisting>
<para>If a proper <literal>const.cfg</literal> is provided, the
unreachable code is detected:</para>
<programlisting># cppcheck --enable=style --library=pure pure.c
Checking pure.c...
[pure.c:7]: (style) Expression is always false because 'else if' condition matches previous condition at line 5.</programlisting>
<programlisting># cppcheck --enable=style --library=const const.c
Checking const.c...
[const.c:7]: (style) Expression is always false because 'else if' condition matches previous condition at line 5.</programlisting>
<para>Here is a minimal <literal>pure.cfg</literal> file:</para>
<para>Here is a minimal <literal>const.cfg</literal> file:</para>
<programlisting>&lt;?xml version="1.0"?&gt;
&lt;def&gt;
&lt;function name="calculate"&gt;
&lt;pure/&gt;
&lt;const/&gt;
&lt;arg nr="1"/&gt;
&lt;/function&gt;
&lt;/def&gt;</programlisting>