7779a9186e
The unsigned less than zero checker looked for patterns like "<= 0".
Switching to use valueflow improves the checker in a few aspects.
First, it removes false positives where instead of 0, the code is using
0L, 0U, etc. Instead of having to hard code the different variants of 0,
valueflow handles this automatically. This fixes FPs on the form
uint32_t value = 0xFUL;
void f() {
if (value < 0u)
{
value = 0u;
}
}
where 0u was previously not recognized by the checker. This fixes #8836.
Morover, it makes it possible to handle templates properly. In commit
fa076598ade8a751ad85d5375bc976439e32c117, all warnings inside templates
were made inconclusive, since the checker had no idea if "0" came from
a template parameter or not.
This makes it possible to not warn for the following case which was
reported as a FP in #3233
template<int n> void foo(unsigned int x) {
if (x <= n);
}
foo<0>();
but give a warning for the following case
template<int n> void foo(unsigned int x) {
if (x <= 0);
}
Previously, both these cases gave inconclusive warnings.
Finally, it makes it possible to give warnings for the following code:
void f(unsigned x) {
int y = 0;
if (x <= y) {}
}
Also, previously, the checker for unsigned variables larger than 0, the
checker used the string of the astoperand. This meant that for code like
the following:
void f(unsigned x, unsigned y) {
if (x -y >= 0) {}
}
cppcheck would output
[unsigned-expression-positive.c] (style) Unsigned variable '-' can't be negative so it is unnecessary to test it.
using expressionString() instead gives a better error message
[unsigned-expression-positive.c] (style) Unsigned expression 'x-z' can't be negative so it is unnecessary to test it.
Cppcheck
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Donations
If you find Cppcheck useful for you, feel free to make a donation.
About the name
The original name of this program was "C++check", but it was later changed to "Cppcheck".
Despite the name, Cppcheck is designed for both C and C++.
Manual
A manual is available online.
Compiling
Any C++11 compiler should work. For compilers with partial C++11 support it may work. If your compiler has the C++11 features that are available in Visual Studio 2013 / GCC 4.6 then it will work.
To build the GUI, you need Qt.
When building the command line tool, PCRE is optional. It is used if you build with rules.
There are multiple compilation choices:
- qmake - cross platform build tool
- cmake - cross platform build tool
- Windows: Visual Studio (VS 2013 and above)
- Windows: Qt Creator + mingw
- gnu make
- g++ 4.6 (or later)
- clang++
qmake
You can use the gui/gui.pro file to build the GUI.
cd gui
qmake
make
Visual Studio
Use the cppcheck.sln file. The file is configured for Visual Studio 2015, but the platform toolset can be changed easily to older or newer versions. The solution contains platform targets for both x86 and x64.
To compile with rules, select "Release-PCRE" or "Debug-PCRE" configuration. pcre.lib (pcre64.lib for x64 builds) and pcre.h are expected to be in /externals then.
Qt Creator + MinGW
The PCRE dll is needed to build the CLI. It can be downloaded here: http://software-download.name/pcre-library-windows/
GNU make
Simple, unoptimized build (no dependencies):
make
The recommended release build is:
make SRCDIR=build CFGDIR=cfg HAVE_RULES=yes CXXFLAGS="-O2 -DNDEBUG -Wall -Wno-sign-compare -Wno-unused-function"
Flags:
-
SRCDIR=build
Python is used to optimise cppcheck -
CFGDIR=cfg
Specify folder where .cfg files are found -
HAVE_RULES=yes
Enable rules (PCRE is required if this is used) -
CXXFLAGS="-O2 -DNDEBUG -Wall -Wno-sign-compare -Wno-unused-function"Enables most compiler optimizations, disables cppcheck-internal debugging code and enables basic compiler warnings.
g++ (for experts)
If you just want to build Cppcheck without dependencies then you can use this command:
g++ -o cppcheck -std=c++11 -Iexternals/simplecpp -Iexternals/tinyxml -Ilib cli/*.cpp lib/*.cpp externals/simplecpp/simplecpp.cpp externals/tinyxml/*.cpp
If you want to use --rule and --rule-file then dependencies are needed:
g++ -o cppcheck -std=c++11 -lpcre -DHAVE_RULES -Ilib -Iexternals/simplecpp -Iexternals/tinyxml cli/*.cpp lib/*.cpp externals/simplecpp/simplecpp.cpp externals/tinyxml/*.cpp
MinGW
mingw32-make LDFLAGS=-lshlwapi
Other Compiler/IDE
- Create a empty project file / makefile.
- Add all cpp files in the cppcheck cli and lib folders to the project file / makefile.
- Add all cpp files in the externals folders to the project file / makefile.
- Compile.
Cross compiling Win32 (CLI) version of Cppcheck in Linux
sudo apt-get install mingw32
make CXX=i586-mingw32msvc-g++ LDFLAGS="-lshlwapi" RDYNAMIC=""
mv cppcheck cppcheck.exe