75 lines
2.4 KiB
ReStructuredText
75 lines
2.4 KiB
ReStructuredText
|
.. title:: clang-tidy - modernize-use-std-numbers
|
||
|
|
|
||
|
|
modernize-use-std-numbers
|
||
|
|
=========================
|
||
|
|
|
||
|
|
Finds constants and function calls to math functions that can be replaced
|
||
|
|
with C++20's mathematical constants from the ``numbers`` header and offers
|
||
|
|
fix-it hints.
|
||
|
|
Does not match the use of variables with that value, and instead,
|
||
|
|
offers a replacement for the definition of those variables.
|
||
|
|
Function calls that match the pattern of how the constant is calculated are
|
||
|
|
matched and replaced with the ``std::numbers`` constant.
|
||
|
|
The use of macros gets replaced with the corresponding ``std::numbers``
|
||
|
|
constant, instead of changing the macro definition.
|
||
|
|
|
||
|
|
The following list of constants from the ``numbers`` header are supported:
|
||
|
|
|
||
|
|
* ``e``
|
||
|
|
* ``log2e``
|
||
|
|
* ``log10e``
|
||
|
|
* ``pi``
|
||
|
|
* ``inv_pi``
|
||
|
|
* ``inv_sqrtpi``
|
||
|
|
* ``ln2``
|
||
|
|
* ``ln10``
|
||
|
|
* ``sqrt2``
|
||
|
|
* ``sqrt3``
|
||
|
|
* ``inv_sqrt3``
|
||
|
|
* ``egamma``
|
||
|
|
* ``phi``
|
||
|
|
|
||
|
|
The list currently includes all constants as of C++20.
|
||
|
|
|
||
|
|
The replacements use the type of the matched constant and can remove explicit
|
||
|
|
casts, i.e., switching between ``std::numbers::e``,
|
||
|
|
``std::numbers::e_v<float>`` and ``std::numbers::e_v<long double>`` where
|
||
|
|
appropriate.
|
||
|
|
|
||
|
|
.. code-block:: c++
|
||
|
|
|
||
|
|
double sqrt(double);
|
||
|
|
double log2(double);
|
||
|
|
void sink(auto&&) {}
|
||
|
|
void floatSink(float);
|
||
|
|
|
||
|
|
#define MY_PI 3.1415926
|
||
|
|
|
||
|
|
void foo() {
|
||
|
|
const double Pi = 3.141592653589; // const double Pi = std::numbers::pi
|
||
|
|
const auto Use = Pi / 2; // no match for Pi
|
||
|
|
static constexpr double Euler = 2.7182818; // static constexpr double Euler = std::numbers::e;
|
||
|
|
|
||
|
|
log2(exp(1)); // std::numbers::log2e;
|
||
|
|
log2(Euler); // std::numbers::log2e;
|
||
|
|
1 / sqrt(MY_PI); // std::numbers::inv_sqrtpi;
|
||
|
|
sink(MY_PI); // sink(std::numbers::pi);
|
||
|
|
floatSink(MY_PI); // floatSink(std::numbers::pi);
|
||
|
|
floatSink(static_cast<float>(MY_PI)); // floatSink(std::numbers::pi_v<float>);
|
||
|
|
}
|
||
|
|
|
||
|
|
Options
|
||
|
|
-------
|
||
|
|
|
||
|
|
.. option:: DiffThreshold
|
||
|
|
|
||
|
|
A floating point value that sets the detection threshold for when literals
|
||
|
|
match a constant. A literal matches a constant if
|
||
|
|
``abs(literal - constant) < DiffThreshold`` evaluates to ``true``. Default
|
||
|
|
is `0.001`.
|
||
|
|
|
||
|
|
.. option:: IncludeStyle
|
||
|
|
|
||
|
|
A string specifying which include-style is used, `llvm` or `google`. Default
|
||
|
|
is `llvm`.
|