Cppcheck¶

Features¶

Cppcheck supports a wide variety of static checks that may not be covered by the compiler itself. These checks are static analysis checks that can be performed at a source code level. The program is directed towards static analysis checks that are rigorous, rather than heuristic in nature.

Some of the defects that might be detected include:

• Automatic variable checking

• Bounds checking for array overruns

• Classes checking (e.g. unused functions, variable initialization, and memory duplication)

• Usage of deprecated or superseded functions

• Exception safety checking, for example, usage of memory allocation and destructor checks

• Memory leaks, e.g. due to lost scope without deallocation

• Resource leaks, e.g. due to forgetting to close a file handle

• Invalid usage of Standard Template Library functions and idioms

• Miscellaneous stylistic and performance errors

Additional checks¶

Be default Cppcheck is configured to check the next additional defects:

• warning

• style

• performance

• portability

• unusedFunction

The full list of supported check with detailed description is located on the official webpage.

Configuration¶

Cppcheck is implicitly used as the default check tool when check_tool option in “platformio.ini” (Project Configuration File) is not set. To be explicit, you can specify it in the configuration directly:

[env:myenv]
platform = ...
board = ...
check_tool = cppcheck
check_flags = --enable=all

Useful options that can be used used for adjusting check process:

Extra flags¶

Useful flags that can help more precisely configure Cppcheck to satisfy your project requirements:

Flag	Meaning
--enable=<id>	Enable additional checks. The available ids are: all, warning, style, performance, portability, information, unusedFunction, missingInclude
--std=<id>	Set standard. The available options are: c89, c99, c11, c++03, c++11, c++14, c++17, c++20 (default)
--language=<language>	Forces Cppcheck to check all files as the given language. Valid values are: c, c++
--inline-suppr	Enable inline suppressions. Use them by placing one or more comments, like: // cppcheck-suppress warningId on the lines before the warning to suppress (enabled by default if no extra flags specified).
--suppress=<spec>	Suppress warnings that match <spec>. The format of <spec> is: [error id]:[filename]:[line]
--platform=<type>	Specifies platform-specific types and sizes. The available built-in platforms are: unix32, unix64, win32A, win32W, win64, avr8, native, unspecified (default)
--inconclusive	Allow reporting defects even though the analysis is inconclusive.
-D<ID>	Define a preprocessor symbol. Example: -DDEBUG=1
-U<ID>	Undefine preprocessor symbol. Use -U to explicitly hide certain #ifdef <ID> code paths from checking. Example: -UDEBUG
-I <dir>	Give a path to search for include files. Give several -I parameters to give several paths.
-j <jobs>	Start <jobs> threads to do the checking simultaneously.

Suppressing warnings¶

It might be useful to explicitly instruct Cppcheck to ignore some of the known defects in project codebase. Since --inline-suppr is enabled by default, it’s possible to directly mark pieces of code that will be excluded from Cppcheck report using // cppcheck-suppress warningId syntax.

By default, PIO Check command doesn’t scan framework sources and that’s why some functions from in your project might be reported as unused. For example, you can ignore warnings about setup and loop functions from Arduino-based projects:

// cppcheck-suppress unusedFunction
void setup()
{
  ...
}

// cppcheck-suppress unusedFunction
void loop()
{
  ...
}

Addons (MISRA, CERT)¶

Cppcheck provides several addon scripts that analyze dump files to check compatibility with secure coding standards and to locate various issues. Most useful addons for verifying compliance with popular guidelines are MISRA and CERT.

Appendix A Summary of guidelines
Rule 3.1 Required
R3.1 Rule description
Rule 4.1 Required
...
Rule 21.3 Required
R21.3 Rule description
Rule 21.4
R21.4 Rule description

{
  "script": "addons/misra.py",
  "args": ["--rule-texts=misra-rules.txt"]
}

[env:myenv]
platform = ...
board = ...
check_tool = cppcheck
check_flags =
  cppcheck: --addon=misra.json

[env:myenv]
platform = ...
board = ...
check_tool = cppcheck
check_flags =
  cppcheck: --addon=cert.py