| .. title:: clang-tidy - cert-dcl21-cpp |
| |
| cert-dcl21-cpp |
| ============== |
| |
| This check flags postfix ``operator++`` and ``operator--`` declarations |
| if the return type is not a const object. This also warns if the return type |
| is a reference type. |
| |
| The object returned by a postfix increment or decrement operator is supposed |
| to be a snapshot of the object's value prior to modification. With such an |
| implementation, any modifications made to the resulting object from calling |
| operator++(int) would be modifying a temporary object. Thus, such an |
| implementation of a postfix increment or decrement operator should instead |
| return a const object, prohibiting accidental mutation of a temporary object. |
| Similarly, it is unexpected for the postfix operator to return a reference to |
| its previous state, and any subsequent modifications would be operating on a |
| stale object. |
| |
| This check corresponds to the CERT C++ Coding Standard recommendation |
| DCL21-CPP. Overloaded postfix increment and decrement operators should return a |
| const object. However, all of the CERT recommendations have been removed from |
| public view, and so their justification for the behavior of this check requires |
| an account on their wiki to view. |
