<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Cppcheck 1.46</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"></HEAD ><BODY CLASS="book" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="BOOK" ><A NAME="AEN1" ></A ><DIV CLASS="TITLEPAGE" ><H1 CLASS="title" ><A NAME="AEN2" >Cppcheck 1.46</A ></H1 ><HR></DIV ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >1. <A HREF="#AEN5" >Introduction</A ></DT ><DT >2. <A HREF="#AEN19" >Getting started</A ></DT ><DD ><DL ><DT >2.1. <A HREF="#AEN21" >First test</A ></DT ><DT >2.2. <A HREF="#AEN30" >Checking all files in a folder</A ></DT ><DT >2.3. <A HREF="#AEN36" >Excluding a file or folder from checking</A ></DT ><DT >2.4. <A HREF="#AEN44" >Severities</A ></DT ><DT >2.5. <A HREF="#AEN65" >Enable messages</A ></DT ><DD ><DL ><DT >2.5.1. <A HREF="#AEN70" >Stylistic issues</A ></DT ><DT >2.5.2. <A HREF="#AEN84" >Unused functions</A ></DT ><DT >2.5.3. <A HREF="#AEN88" >Enable all checks</A ></DT ></DL ></DD ><DT >2.6. <A HREF="#AEN93" >Saving results in file</A ></DT ><DT >2.7. <A HREF="#AEN97" >Multithreaded checking</A ></DT ></DL ></DD ><DT >3. <A HREF="#AEN101" >Preprocessor configurations</A ></DT ><DT >4. <A HREF="#AEN109" >XML output</A ></DT ><DT >5. <A HREF="#AEN143" >Reformatting the output</A ></DT ><DT >6. <A HREF="#AEN159" >Suppressions</A ></DT ><DT >7. <A HREF="#AEN172" >Leaks</A ></DT ><DD ><DL ><DT >7.1. <A HREF="#AEN175" >Userdefined allocation/deallocation functions</A ></DT ></DL ></DD ><DT >8. <A HREF="#AEN192" >Exception safety</A ></DT ><DT >9. <A HREF="#AEN212" >Html report</A ></DT ><DT >10. <A HREF="#AEN224" >Graphical user interface</A ></DT ><DD ><DL ><DT >10.1. <A HREF="#AEN226" >Introduction</A ></DT ><DT >10.2. <A HREF="#AEN230" >Check source code</A ></DT ><DT >10.3. <A HREF="#AEN234" >Inspecting results</A ></DT ><DT >10.4. <A HREF="#AEN242" >Settings</A ></DT ><DT >10.5. <A HREF="#AEN249" >Project files</A ></DT ></DL ></DD ></DL ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN5" ></A >Chapter 1. Introduction</H1 ><P >Cppcheck is an analysis tool for C/C++ code. Unlike C/C++ compilers and many other analysis tools, it doesn't detect syntax errors. Cppcheck only detects the types of bugs that the compilers normally fail to detect. The goal is no false positives.</P ><P >Supported code and platforms:</P ><P ></P ><UL ><LI ><P >You can check non-standard code that includes various compiler extensions, inline assembly code, etc.</P ></LI ><LI ><P >Cppcheck should be compilable by any C++ compiler that handles the latest C++ standard.</P ></LI ><LI ><P >Cppcheck should work on any platform that has sufficient cpu and memory.</P ></LI ></UL ><P >Accuracy</P ><P >Please understand that there are limits of Cppcheck. Cppcheck is rarely wrong about reported errors. But there are many bugs that it doesn't detect.</P ><P >You will find more bugs in your software by testing your software carefully, than by using Cppcheck. You will find more bugs in your software by instrumenting your software, than by using Cppcheck. But Cppcheck can still detect some of the bugs that you miss when testing and instrumenting your software.</P ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN19" ></A >Chapter 2. Getting started</H1 ><DIV CLASS="section" ><H2 CLASS="section" ><A NAME="AEN21" >2.1. First test</A ></H2 ><P >Here is a simple code</P ><PRE CLASS="programlisting" >int main() { char a[10]; a[10] = 0; return 0; }</PRE ><P >If you save that into <TT CLASS="filename" >file1.c</TT > and execute:</P ><PRE CLASS="programlisting" >cppcheck file1.c</PRE ><P >The output from cppcheck will then be:</P ><PRE CLASS="programlisting" >Checking file1.c... [file1.c:4]: (error) Array 'a[10]' index 10 out of bounds</PRE ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN30" >2.2. Checking all files in a folder</A ></H2 ><P >Normally a program has many sourcefiles. And you want to check them all. Cppcheck can check all sourcefiles in a directory:</P ><PRE CLASS="programlisting" >cppcheck path</PRE ><P >If "path" is a folder then cppcheck will check all sourcefiles in this folder.</P ><PRE CLASS="programlisting" >Checking path/file1.cpp... 1/2 files checked 50% done Checking path/file2.cpp... 2/2 files checked 100% done</PRE ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN36" >2.3. Excluding a file or folder from checking</A ></H2 ><P >There is no command to exclude a file or folder from checking. But you can exclude a file or folder by being more careful when including files and folders in the checking.</P ><P >Imagine for example that the folder "src" contain the folders "a", "b" and "c". To exclude "c" this command can be used:</P ><PRE CLASS="programlisting" >cppcheck src/a src/b</PRE ><P >All files under "src/a" and "src/b" are then checked.</P ><P >The flag <TT CLASS="literal" >--file-list</TT > might also be useful.</P ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN44" >2.4. Severities</A ></H2 ><P >The possible severities for messages are:</P ><P ></P ><DIV CLASS="variablelist" ><DL ><DT >error</DT ><DD ><P >used when bugs are found</P ></DD ><DT >warning</DT ><DD ><P >suggestions about defensive programming to prevent bugs</P ></DD ><DT >style</DT ><DD ><P >stylistic issues related to code cleanup (unused functions, redundant code, constness, and such)</P ></DD ><DT >performance</DT ><DD ><P >suggestions for making the code faster</P ></DD ></DL ></DIV ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN65" >2.5. Enable messages</A ></H2 ><P >By default only <TT CLASS="literal" >error</TT > messages are shown. Through the <TT CLASS="literal" >--enable</TT > command more checks can be enabled.</P ><DIV CLASS="section" ><HR><H3 CLASS="section" ><A NAME="AEN70" >2.5.1. Stylistic issues</A ></H3 ><P >With <TT CLASS="literal" >--enable=style</TT > you enable most <TT CLASS="literal" >warning</TT >, <TT CLASS="literal" >style</TT > and <TT CLASS="literal" >performance</TT > messages.</P ><P >Here is a simple code example:</P ><PRE CLASS="programlisting" >void f(int x) { int i; if (x == 0) { i = 0; } }</PRE ><P >There are no bugs in that code so Cppcheck won't report anything by default. To enable the stylistic messages, use the --enable=style command:</P ><PRE CLASS="programlisting" >cppcheck --enable=style file3.c</PRE ><P >The output from Cppcheck is now:</P ><P ><PRE CLASS="programlisting" >Checking file3.c... [file3.c:3]: (style) Variable 'i' is assigned a value that is never used [file3.c:3]: (style) The scope of the variable i can be reduced</PRE ></P ></DIV ><DIV CLASS="section" ><HR><H3 CLASS="section" ><A NAME="AEN84" >2.5.2. Unused functions</A ></H3 ><P >This check will try to find unused functions. It is best to use this when the whole program is checked, so that all usages is seen by cppcheck.</P ><PRE CLASS="programlisting" >cppcheck --enable=unusedFunction path</PRE ></DIV ><DIV CLASS="section" ><HR><H3 CLASS="section" ><A NAME="AEN88" >2.5.3. Enable all checks</A ></H3 ><P >To enable all checks your can use the <TT CLASS="literal" >--enable=all</TT > flag:</P ><PRE CLASS="programlisting" >cppcheck --enable=all path</PRE ></DIV ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN93" >2.6. Saving results in file</A ></H2 ><P >Many times you will want to save the results in a file. You can use the normal shell redirection for piping error output to a file.</P ><PRE CLASS="programlisting" >cppcheck file1.c 2> err.txt</PRE ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN97" >2.7. Multithreaded checking</A ></H2 ><P >To use 4 threads to check the files in a folder:</P ><PRE CLASS="programlisting" >cppcheck -j 4 path</PRE ></DIV ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN101" ></A >Chapter 3. Preprocessor configurations</H1 ><P >By default Cppcheck will check all preprocessor configurations (except those that have #error in them). This is the recommended behaviour.</P ><P >But if you want to manually limit the checking you can do so with <TT CLASS="literal" >-D</TT >.</P ><P >Beware that only the macros, which are given here and the macros defined in source files and known header files are considered. That excludes all the macros defined in some system header files, which are by default not examined by cppcheck.</P ><P >The usage: if you, for example, want to limit the checking so the only configuration to check should be "DEBUG=1;__cplusplus" then something like this can be used:</P ><PRE CLASS="programlisting" >cppcheck -DDEBUG=1 -D__cplusplus path</PRE ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN109" ></A >Chapter 4. XML output</H1 ><P >Cppcheck can generate the output in XML format.</P ><P >Use the --xml flag when you execute cppcheck:</P ><PRE CLASS="programlisting" >cppcheck --xml file1.cpp</PRE ><P >The xml format is:</P ><PRE CLASS="programlisting" ><?xml version="1.0"?> <results> <error file="file1.cpp" line="123" id="someError" severity="error" msg="some error text"/> </results></PRE ><P >Attributes:</P ><P ></P ><DIV CLASS="variablelist" ><DL ><DT >file</DT ><DD ><P >filename. Both relative and absolute paths are possible</P ></DD ><DT >line</DT ><DD ><P >a number</P ></DD ><DT >id</DT ><DD ><P >id of error. These are always valid symbolnames.</P ></DD ><DT >severity</DT ><DD ><P >either <TT CLASS="literal" >error</TT > or <TT CLASS="literal" >style</TT >. <TT CLASS="literal" >warning</TT > and <TT CLASS="literal" >performance</TT > are saved as <TT CLASS="literal" >style</TT >.</P ></DD ><DT >msg</DT ><DD ><P >the error message</P ></DD ></DL ></DIV ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN143" ></A >Chapter 5. Reformatting the output</H1 ><P >If you want to reformat the output so it looks different you can use templates.</P ><P >To get Visual Studio compatible output you can use "--template vs":</P ><PRE CLASS="programlisting" >cppcheck --template vs gui/test.cpp</PRE ><P >This output will look like this:</P ><PRE CLASS="programlisting" >Checking gui/test.cpp... gui/test.cpp(31): error: Memory leak: b gui/test.cpp(16): error: Mismatching allocation and deallocation: k</PRE ><P >To get gcc compatible output you can use "--template gcc":</P ><PRE CLASS="programlisting" >cppcheck --template gcc gui/test.cpp</PRE ><P >The output will look like this:</P ><PRE CLASS="programlisting" >Checking gui/test.cpp... gui/test.cpp:31: error: Memory leak: b gui/test.cpp:16: error: Mismatching allocation and deallocation: k</PRE ><P >You can write your own pattern (for example a comma-separated format):</P ><PRE CLASS="programlisting" >cppcheck --template "{file},{line},{severity},{id},{message}" gui/test.cpp</PRE ><P >The output will look like this:</P ><PRE CLASS="programlisting" >Checking gui/test.cpp... gui/test.cpp,31,error,memleak,Memory leak: b gui/test.cpp,16,error,mismatchAllocDealloc,Mismatching allocation and deallocation: k</PRE ><P ></P ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN159" ></A >Chapter 6. Suppressions</H1 ><P >If you want to filter out certain errors you can suppress these. First you need to create a suppressions file. The format is:</P ><PRE CLASS="programlisting" >[error id]:[filename]:[line] [error id]:[filename2] [error id]</PRE ><P >The <TT CLASS="literal" >error id</TT > is the id that you want to suppress. The easiest way to get it is to use the <TT CLASS="literal" >--xml</TT > command line flag. Copy and paste the <TT CLASS="literal" >id</TT > string from the xml output.</P ><P >Here is an example:</P ><PRE CLASS="programlisting" >memleak:file1.cpp exceptNew:file1.cpp uninitvar</PRE ><P >You can then use the suppressions file:</P ><PRE CLASS="programlisting" >cppcheck --suppressions suppressions.txt src/</PRE ><P ></P ></DIV > <DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN192" ></A >Chapter 7. Exception safety</H1 ><P >Cppcheck has a few checks that ensure that you don't break the basic guarantee of exception safety. It doesn't have any checks for the strong guarantee yet.</P ><P >Example:</P ><PRE CLASS="programlisting" >Fred::Fred() : a(new int[20]), b(new int[20]) { }</PRE ><P >By default cppcheck will not detect any problems in that code.</P ><P >To enable the exception safety checking you can use <TT CLASS="literal" >--enable</TT >:</P ><PRE CLASS="programlisting" >cppcheck --enable=exceptNew --enable=exceptRealloc fred.cpp</PRE ><P >The output will be:</P ><PRE CLASS="programlisting" >[fred.cpp:3]: (style) Upon exception there is memory leak: a</PRE ><P >If an exception occurs when <TT CLASS="literal" >b</TT > is allocated, <TT CLASS="literal" >a</TT > will leak.</P ><P >Here is another example:</P ><PRE CLASS="programlisting" >int *p; int a(int sz) { delete [] p; if (sz <= 0) throw std::runtime_error("size <= 0"); p = new int[sz]; }</PRE ><P >Check that with Cppcheck:</P ><PRE CLASS="programlisting" >cppcheck --enable=exceptNew --enable=exceptRealloc except2.cpp</PRE ><P >The output from Cppcheck is:</P ><PRE CLASS="programlisting" >[except2.cpp:7]: (error) Throwing exception in invalid state, p points at deallocated memory</PRE ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN212" ></A >Chapter 8. Html report</H1 ><P >You can convert the xml output from cppcheck into a html report. You'll need python and the pygments module (<FONT COLOR="RED" >http://pygments.org/</FONT >) for this to work. In the Cppcheck source tree there is a folder "htmlreport" that contains a script that transforms a Cppcheck xml file into html output.</P ><P >This command generates the help screen:</P ><P ><PRE CLASS="programlisting" >htmlreport/cppcheck-htmlreport -h</PRE ></P ><P >The output screen says:</P ><P ><PRE CLASS="programlisting" >Usage: cppcheck-htmlreport [options] Options: -h, --help show this help message and exit --file=FILE The cppcheck xml output file to read defects from. Default is reading from stdin. --report-dir=REPORT_DIR The directory where the html report content is written. --source-dir=SOURCE_DIR Base directory where source code files can be found.</PRE ></P ><P >An example usage:</P ><PRE CLASS="programlisting" >./cppcheck gui/test.cpp --xml 2> err.xml htmlreport/cppcheck-htmlreport --file=err.xml --report-dir=test1 --source-dir=.</PRE ></DIV ><DIV CLASS="chapter" ><HR><H1 ><A NAME="AEN224" ></A >Chapter 9. Graphical user interface</H1 ><DIV CLASS="section" ><H2 CLASS="section" ><A NAME="AEN226" >9.1. Introduction</A ></H2 ><P >A Cppcheck GUI is available.</P ><P >The main screen is shown immediately when the GUI is started.</P ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN230" >9.2. Check source code</A ></H2 ><P >Use the <TT CLASS="literal" >Check</TT > menu.</P ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN234" >9.3. Inspecting results</A ></H2 ><P >The results are shown in a list.</P ><P >You can show/hide certain types of messages through the <TT CLASS="literal" >View</TT > menu.</P ><P >Results can be saved to an xml file that can later be opened. See <TT CLASS="literal" >Save results to file</TT > and <TT CLASS="literal" >Open XML</TT >.</P ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN242" >9.4. Settings</A ></H2 ><P >The language can be changed at any time by using the <TT CLASS="literal" >Language</TT > menu.</P ><P >More settings are available in <TT CLASS="literal" >Edit</TT >><TT CLASS="literal" >Preferences</TT >.</P ></DIV ><DIV CLASS="section" ><HR><H2 CLASS="section" ><A NAME="AEN249" >9.5. Project files</A ></H2 ><P >The project files are used to store project specific settings. These settings are:</P ><P ></P ><UL ><LI ><P >include folders</P ></LI ><LI ><P >preprocessor defines</P ></LI ></UL ><P >It isn't recommended to provide the paths to the standard C/C++ headers - Cppcheck has internal knowledge about ANSI C/C++ and it isn't recommended that this known functionality is redefined. But feel free to try it.</P ><P >As you can read in chapter 3 in this manual the default is that Cppcheck checks all configurations. So only provide preprocessor defines if you want to limit the checking.</P ></DIV ></DIV ></DIV ></BODY ></HTML >