.. title:: clang-tidy - cppcoreguidelines-macro-usage
cppcoreguidelines-macro-usage
=============================
Finds macro usage that is considered problematic because better language
constructs exist for the task.
The relevant sections in the C++ Core Guidelines are
`ES.31 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#es31-dont-use-macros-for-constants-or-functions>`_, and
`ES.32 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#es32-use-all_caps-for-all-macro-names>`_.
Examples:
.. code-block:: c++
#define C 0
#define F1(x, y) ((a) > (b) ? (a) : (b))
#define F2(...) (__VA_ARGS__)
#define F3(x, y) x##y
#define COMMA ,
#define NORETURN [[noreturn]]
#define DEPRECATED attribute((deprecated))
#if LIB_EXPORTS
#define DLLEXPORTS __declspec(dllexport)
#else
#define DLLEXPORTS __declspec(dllimport)
#endif
results in the following warnings::
4 warnings generated.
test.cpp:1:9: warning: macro 'C' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage]
#define C 0
^
test.cpp:2:9: warning: function-like macro 'F1' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage]
#define F1(x, y) ((a) > (b) ? (a) : (b))
^
test.cpp:3:9: warning: variadic macro 'F2' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage]
#define F2(...) (__VA_ARGS__)
^
Options
-------
.. option:: AllowedRegexp
A regular expression to filter allowed macros. For example
`DEBUG*|LIBTORRENT*|TORRENT*|UNI*` could be applied to filter `libtorrent`.
Default value is `^DEBUG_*`.
.. option:: CheckCapsOnly
Boolean flag to warn on all macros except those with CAPS_ONLY names.
This option is intended to ease introduction of this check into older
code bases. Default value is `false`.
.. option:: IgnoreCommandLineMacros
Boolean flag to toggle ignoring command-line-defined macros.
Default value is `true`.
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