Manual: Minor refactorings
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Daniel Marjamäki
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@ -5,22 +5,22 @@
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<bookinfo>
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<title>Cppcheck</title>
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<date>2009-10-11</date>
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<date>2009-11-14</date>
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</bookinfo>
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<chapter>
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<title>Introduction</title>
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<para>Cppcheck is a static analysis tool for C/C++ code - it textually
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inspects the source code to detect bugs.</para>
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inspects your C/C++ source code to detect bugs.</para>
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<para>Cppcheck detects issues that you will not find with your compiler.
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But Cppcheck doesn't detect the types of bugs that compilers
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detect.</para>
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<para>It is our goal to generate no false positives. We always try to
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achieve 0 false positives. It means that there will always be issues that
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Cppcheck fail to detect.</para>
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achieve 0 false positives. There will always be issues that Cppcheck fail
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to detect.</para>
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<para>Supported platforms:</para>
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@ -40,8 +40,6 @@
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cpu and memory.</para>
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</listitem>
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</itemizedlist>
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<para></para>
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</chapter>
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<chapter>
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@ -88,12 +86,30 @@ Checking path/file2.cpp...
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</section>
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<section>
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<title>Uncertain errors</title>
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<title>Possible errors</title>
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<para>By default, only certain errors are reported.</para>
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<para>By default, an error is only reported when
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<literal><literal>Cppcheck</literal></literal> is sure there is an
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error.</para>
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<para>With "--all" you will get more reports. But beware - some messages
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may be wrong.</para>
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<para>When a likely issue is discovered, <literal>Cppcheck</literal>
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bails out without reporting this issue - to prevent false positives. But
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with <literal>--all</literal> you can ensure that these issues are
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reported.</para>
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<para>The <literal>--all</literal> flag is useful but makes
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<literal>Cppcheck</literal> more unreliable:</para>
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<itemizedlist>
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<listitem>
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<para>You will probably get false positives</para>
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</listitem>
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<listitem>
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<para>Cppcheck can detect issues that it can't detect by
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default</para>
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</listitem>
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</itemizedlist>
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<para>Here is a simple code example:</para>
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@ -145,7 +161,8 @@ Checking path/file2.cpp...
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<para>Many times you will want to save the results in a file. The
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results are written to stderr and the progress messages are written to
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stdout. So you can use the standard redirections to save to file.</para>
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stdout. So you can use the normal shell redirections to save to
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file.</para>
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<programlisting>cppcheck file1.c 2> err.txt</programlisting>
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</section>
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@ -216,7 +233,7 @@ Checking path/file2.cpp...
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<term>msg</term>
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<listitem>
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<para>the error message in plain text</para>
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<para>the error message</para>
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</listitem>
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</varlistentry>
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</variablelist>
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@ -339,11 +356,26 @@ QPushButton</programlisting>
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<section>
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<title>Userdefined allocation/deallocation functions</title>
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<para>Cppcheck understands many common allocation and deallocation
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functions. But not all.</para>
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<para><literal>Cppcheck</literal> understands many common allocation and
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deallocation functions. But not all.</para>
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<para>Here is a trick to add custom checking. First we write simple
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implementations for the allocation and deallocation functions:</para>
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<para>Here is example code that might leak memory or resources:</para>
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<para><programlisting>void foo(int x)
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{
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void *f = CreateFred();
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if (x == 1)
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return;
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DestroyFred(f);
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}</programlisting></para>
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<para>If you analyse that with Cppcheck it won't find any leaks:</para>
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<programlisting>cppcheck --all fred1.cpp</programlisting>
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<para>You can add some custom leaks checking by providing simple
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implementations for the allocation and deallocation functions. Write
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this in a separate file:</para>
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<programlisting>void *CreateFred()
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{
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@ -358,18 +390,7 @@ void DestroyFred(void *p)
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<para>When Cppcheck see this it understands that CreateFred will return
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allocated memory and that DestroyFred will deallocate memory.</para>
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<para>Here is an example program that uses CreateFred and
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DestroyFred:</para>
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<programlisting>void foo(int x)
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{
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void *f = CreateFred();
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if (x == 1)
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return;
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DestroyFred(f);
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}</programlisting>
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<para>Execute Cppcheck this way:</para>
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<para>Now, execute <literal>Cppcheck</literal> this way:</para>
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<programlisting>cppcheck --append=fred.cpp fred1.cpp</programlisting>
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@ -399,11 +420,11 @@ void DestroyFred(void *p)
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<para>To enable the exception safety checking you can use
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<literal>--enable</literal>:</para>
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<programlisting>cppcheck --enable except.cpp</programlisting>
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<programlisting>cppcheck --enable fred.cpp</programlisting>
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<para>The output will be:</para>
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<programlisting>[except.cpp:3]: (style) Upon exception there is memory leak: a</programlisting>
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<programlisting>[fred.cpp:3]: (style) Upon exception there is memory leak: a</programlisting>
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<para>If an exception occurs when <literal>b</literal> is allocated,
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<literal>a</literal> will leak.</para>
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