You can import some project files and build configurations into Cppcheck.
### Cppcheck GUI project
You can import and use Cppcheck GUI project files in the command line tool:
cppcheck --project=foobar.cppcheck
### CMake
Generate a compile database:
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON .
The file `compile_commands.json` is created in the current folder. Now run Cppcheck like this:
cppcheck --project=compile_commands.json
### Visual Studio
You can run Cppcheck on individual project files (\*.vcxproj) or on a whole solution (\*.sln)
Running Cppcheck on an entire Visual Studio solution:
cppcheck --project=foobar.sln
Running Cppcheck on a Visual Studio project:
cppcheck --project=foobar.vcxproj
### C++ Builder 6
Running Cppcheck on a C++ Builder 6 project:
cppcheck --project=foobar.bpr
### Other
If you can generate a compile database then it's possible to import that in Cppcheck.
In Linux you can use for instance the `bear` (build ear) utility to generate a compile database from arbitrary build tools:
bear make
## Preprocessor Settings
If you use `--project` then Cppcheck will use the preprocessor settings from the imported project. Otherwise you'll probably want to configure the include paths, defines, etc.
### Defines
Here is a file that has 2 preprocessor configurations (with A defined and without A defined):
#ifdef A
x = y;
#else
x = z;
#endif
By default Cppcheck will check all preprocessor configurations (except those that have #error in them). So the above code will by default be analyzed both with `A` defined and without `A` defined.
You can use `-D` to change this. When you use `-D`, cppcheck will by default only check the given configuration and nothing else. This is how compilers work. But you can use `--force` or `--max-configs` to override the number of configurations.
Check all configurations:
cppcheck file.c
Only check the configuration A:
cppcheck -DA file.c
Check all configurations when macro A is defined
cppcheck -DA --force file.c
Another useful flag might be `-U`. It tells Cppcheck that a macro is not defined. Example usage:
cppcheck -UX file.c
That will mean that X is not defined. Cppcheck will not check what happens when X is defined.
### Include paths
To add an include path, use `-I`, followed by the path.
Cppcheck's preprocessor basically handles includes like any other preprocessor. However, while other preprocessors stop working when they encounter a missing header, cppcheck will just print an information message and continues parsing the code.
The purpose of this behaviour is that cppcheck is meant to work without necessarily seeing the entire code. Actually, it is recommended to not give all include paths. While it is useful for cppcheck to see the declaration of a class when checking the implementation of its members, passing standard library headers is highly discouraged because it will result in worse results and longer checking time. For such cases, .cfg files (see below) are the better way to provide information about the implementation of functions and types to cppcheck.
## Suppressions
If you want to filter out certain errors you can suppress these.
Please note that if you see a false positive then we (the Cppcheck team) want that you report it so we can fix it.
### Plain text suppressions
You can suppress certain types of errors. The format for such a suppression is one of:
[error id]:[filename]:[line]
[error id]:[filename2]
[error id]
The `error id` is the id that you want to suppress. The easiest way to get it is to use the --template=gcc command line flag. The id is shown in brackets.
The filename may include the wildcard characters \* or ?, which match any sequence of characters or any single character respectively. It is recommended that you use "/" as path separator on all operating systems.
### Command line suppression
The `--suppress=` command line option is used to specify suppressions on the command line. Example:
cppcheck --suppress=memleak:src/file1.cpp src/
### Suppressions in a file
You can create a suppressions file. Example:
// suppress memleak and exceptNew errors in the file src/file1.cpp
memleak:src/file1.cpp
exceptNew:src/file1.cpp
// suppress all uninitvar errors in all files
uninitvar
Note that you may add empty lines and comments in the suppressions file.
You can specify suppressions in a XML file. Example file:
<?xml version="1.0"?>
<suppressions>
<suppress>
<id>uninitvar</id>
<fileName>src/file1.c</fileName>
<lineNumber>10</lineNumber>
<symbolName>var</symbolName>
</suppress>
</suppressions>
The xml format is extensible and may be extended with further attributes in the future.
You can use the suppressions file like this:
cppcheck --suppress-xml=suppressions.xml src/
### Inline suppressions
Suppressions can also be added directly in the code by adding comments that contain special keywords. Before adding such comments, consider that the code readability is sacrificed a little.
This code will normally generate an error message:
void f() {
char arr[5];
arr[10] = 0;
}
The output is:
cppcheck test.c
[test.c:3]: (error) Array 'arr[5]' index 10 out of bounds
To suppress the error message, a comment can be added:
void f() {
char arr[5];
// cppcheck-suppress arrayIndexOutOfBounds
arr[10] = 0;
}
Now the `--inline-suppr` flag can be used to suppress the warning. No error is reported when invoking cppcheck this way:
cppcheck --inline-suppr test.c
You can specify that the inline suppression only applies to a specific symbol:
samples/arrayIndexOutOfBounds/bad.c,6,error,arrayIndexOutOfBounds,Array 'a[2]' accessed at index 2, which is out of bounds.
### User defined output format (multi line)
Many warnings have multiple locations. Example code:
void f(int *p)
{
*p = 3; // line 3
}
int main()
{
int *p = 0; // line 8
f(p); // line 9
return 0;
}
There is a possible null pointer dereference at line 3. Cppcheck can show how it came to that conclusion by showing extra location information. You need to use both --template and --template-location at the command line.
multiline.c:3: warning: Possible null pointer dereference: p
*p = 3;
^
multiline.c:8: note: Assignment 'p=0', assigned value is 0
int *p = 0;
^
multiline.c:9: note: Calling function 'f', 1st argument 'p' value is 0
f(p);
^
multiline.c:3: note: Null pointer dereference
*p = 3;
^
The first line in the warning is formatted by the --template format.
The other lines in the warning are formatted by the --template-location format.
#### Format specifiers for --template
The available specifiers for --template are:
**{file}**
File name
**{line}**
Line number
**{column}**
Column number
**{callstack}**
Write all locations. Each location is written in [{file}:{line}] format and the locations are separated by ->. For instance it might look like: [multiline.c:8] -> [multiline.c:9] -> [multiline.c:3]
**{inconclusive:text}**
If warning is inconclusive then the given text is written. The given text can be any arbitrary text that does not contain }. Example: {inconclusive:inconclusive,}
The available specifiers for `--template-location` are:
**{file}**
File name
**{line}**
Line number
**{column}**
Column number
**{info}**
Information message about current location
**{code}**
The real code.
**\t**
Tab
**\t**
Newline
**\r**
Carriage return
## Misra
Cppcheck has an addon that checks for MISRA C 2012 compliance.
### Requirements
You need:
Python 2.X or 3.X
The MISRA C 2012 PDF. You can buy this from http://www.misra.org.uk (costs 15-20 pounds)
#### MISRA Text file
It is not allowed to publish the MISRA rule texts. Therefore the MISRA rule texts are not available directly in the addon. We can not publish the rule texts. Instead, you must provide the rule texts; the addon can read the rule texts from a text file. If you copy/paste all text in "Appendix A Summary of guidelines" from the MISRA pdf, then you have all the rule texts.
If you have installed xpdf, such text file can be generated on the command line (using pdftotext that is included in xpdf):
pdftotext misra-c-2012.pdf output.txt
The output might not be 100% perfect so you might need to make minor tweaks manually.
Other pdf-to-text utilities might work also.
To create the text file manually, copy paste Appendix A "Summary of guidelines" from the MISRA PDF. Format:
Appendix A Summary of guidelines
Rule 1.1
Rule text
Rule 1.2
Rule text
...
Rules that you want to disable does not need to have a rule text. Rules that don't have rule text will be suppressed by the addon.
## Library configuration
When external libraries are used, such as WinAPI, POSIX, gtk, Qt, etc, Cppcheck doesn't know how the external functions behave. Cppcheck then fails to detect various problems such as leaks, buffer overflows, possible null pointer dereferences, etc. But this can be fixed with configuration files.
Cppcheck already contains configurations for several libraries. They can be loaded as described below. Note that the configuration for the standard libraries of C and C++, std.cfg, is always loaded by cppcheck. If you create or update a configuration file for a popular library, we would appreciate if you upload it to us.
You can create and use your own .cfg files for your projects. Use `--check-library` and `--enable=information` to get hints about what you should configure.
It is recommended that you use the `Library Editor` in the `Cppcheck GUI` to edit configuration files. It is available in the `View` menu. Not all settings are documented in this manual yet.
If you have a question about the .cfg file format it is recommended that you ask in the forum (<http://sourceforge.net/p/cppcheck/discussion/>).
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.
The cppcheck GUI will try to load custom .cfg files from the project file path. The custom .cfg files should be shown in the `Edit Project File` dialog that you open from the `File` menu.
