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Cppcheck Design: some more tweaks

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Daniel Marjamäki 2010-12-29 18:03:57 +01:00
parent 38e7209d26
commit 8dae9bcbf7
1 changed files with 35 additions and 9 deletions
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44
man/cppcheck-design.docbook
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@ -23,13 +23,16 @@
<section>
<title>Introduction</title>
<para>This article contains an overview of how Cppcheck works.</para>
<para>The goal with this article is to give users an idea of how Cppcheck
works.</para>
<para>The primary goal is that Cppcheck won't write any false warnings.
This means that when an error is reported there must definitely be a bug
in the code.</para>
<para>Cppcheck is a static analysis tool that tries to completely avoid
false warnings. A false warning is when the tool reports that there is an
error even though there is no error.</para>
<para>The secondary goal is to detect as many bugs as possible.</para>
<para>Cppcheck is a relatively simple tool. I hope that this article will
highlight that it is possible to avoid false warnings with simple
analysis.</para>
</section>
<section>
@ -48,15 +51,38 @@ int days(int hours)
therefore he could see that "23" is wrong. A tool will probably not know
that there are 24 hours in a day.</para>
<para>A tool that tries to guarantee that all bugs are found could write a
warning message for every "suspicious" calculation in the program. It
might correctly report that "hours / 23" is wrong but incorrectly warn
about "hours / 24".</para>
<para>A tool that tries to detect all bugs could write a warning message
for every calculation in the program. Then it will correctly report that
"hours / 23" is wrong but incorrectly warn about "hours / 24".</para>
<para>Cppcheck will only write a warning message if it can determine that
the calculation is wrong. In this case, no error will be written.</para>
</section>
<section>
<title>Control flow analysis</title>
<para>Control flow analysis is when the tool tries to determine if certain
execution paths are possible.</para>
<programlisting>void f(int x)
{
if (x == 1)
f1();
if (x &amp; 2)
f2();
}</programlisting>
<para>The function has 3 possible execution paths. The analysis you do in
your head when you determine that there are 3 possible execution paths is
"control flow analysis".</para>
<para>When you review code you will probably use "control flow analysis"
in your head to determine if there are bugs or not.</para>
<para>The control flow analysis in Cppcheck is quite simple.</para>
</section>
<section>
<title>Buffer overflows</title>