1.. title:: clang-tidy - bugprone-standalone-empty 2 3bugprone-standalone-empty 4========================= 5 6Warns when ``empty()`` is used on a range and the result is ignored. Suggests 7``clear()`` if it is an existing member function. 8 9The ``empty()`` method on several common ranges returns a Boolean indicating 10whether or not the range is empty, but is often mistakenly interpreted as 11a way to clear the contents of a range. Some ranges offer a ``clear()`` 12method for this purpose. This check warns when a call to empty returns a 13result that is ignored, and suggests replacing it with a call to ``clear()`` 14if it is available as a member function of the range. 15 16For example, the following code could be used to indicate whether a range 17is empty or not, but the result is ignored: 18 19.. code-block:: c++ 20 21 std::vector<int> v; 22 ... 23 v.empty(); 24 25A call to ``clear()`` would appropriately clear the contents of the range: 26 27.. code-block:: c++ 28 29 std::vector<int> v; 30 ... 31 v.clear(); 32 33Limitations: 34 35* Doesn't warn if ``empty()`` is defined and used with the ignore result in the 36 class template definition (for example in the library implementation). These 37 error cases can be caught with ``[[nodiscard]]`` attribute. 38