1.. title:: clang-tidy - bugprone-unique-ptr-array-mismatch 2 3bugprone-unique-ptr-array-mismatch 4================================== 5 6Finds initializations of C++ unique pointers to non-array type that are 7initialized with an array. 8 9If a pointer ``std::unique_ptr<T>`` is initialized with a new-expression 10``new T[]`` the memory is not deallocated correctly. A plain ``delete`` is used 11in this case to deallocate the target memory. Instead a ``delete[]`` call is 12needed. A ``std::unique_ptr<T[]>`` uses the correct delete operator. The check 13does not emit warning if an ``unique_ptr`` with user-specified deleter type is 14used. 15 16The check offers replacement of ``unique_ptr<T>`` to ``unique_ptr<T[]>`` if it 17is used at a single variable declaration (one variable in one statement). 18 19Example: 20 21.. code-block:: c++ 22 23 std::unique_ptr<Foo> x(new Foo[10]); // -> std::unique_ptr<Foo[]> x(new Foo[10]); 24 // ^ warning: unique pointer to non-array is initialized with array 25 std::unique_ptr<Foo> x1(new Foo), x2(new Foo[10]); // no replacement 26 // ^ warning: unique pointer to non-array is initialized with array 27 28 D d; 29 std::unique_ptr<Foo, D> x3(new Foo[10], d); // no warning (custom deleter used) 30 31 struct S { 32 std::unique_ptr<Foo> x(new Foo[10]); // no replacement in this case 33 // ^ warning: unique pointer to non-array is initialized with array 34 }; 35 36This check partially covers the CERT C++ Coding Standard rule 37`MEM51-CPP. Properly deallocate dynamically allocated resources 38<https://wiki.sei.cmu.edu/confluence/display/cplusplus/MEM51-CPP.+Properly+deallocate+dynamically+allocated+resources>`_ 39However, only the ``std::unique_ptr`` case is detected by this check. 40