clang-tools-extra/docs/clang-tidy/checks/bugprone-integer-division.rst

.. title:: clang-tidy - bugprone-integer-division

bugprone-integer-division
=========================

Finds cases where integer division in a floating point context is likely to
cause unintended loss of precision.

No reports are made if divisions are part of the following expressions:

- operands of operators expecting integral or bool types,
- call expressions of integral or bool types, and
- explicit cast expressions to integral or bool types,

as these are interpreted as signs of deliberateness from the programmer.

Examples:

.. code-block:: c++

  float floatFunc(float);
  int intFunc(int);
  double d;
  int i = 42;

  // Warn, floating-point values expected.
  d = 32 * 8 / (2 + i);
  d = 8 * floatFunc(1 + 7 / 2);
  d = i / (1 << 4);

  // OK, no integer division.
  d = 32 * 8.0 / (2 + i);
  d = 8 * floatFunc(1 + 7.0 / 2);
  d = (double)i / (1 << 4);

  // OK, there are signs of deliberateness.
  d = 1 << (i / 2);
  d = 9 + intFunc(6 * i / 32);
  d = (int)(i / 32) - 8;