clang-tidy - bugprone-casting-through-void — Extra Clang Tools 18.1.8 documentation

# Extra Clang Tools 18.1.8 documentation

## clang-tidy - bugprone-casting-through-void

# bugprone-casting-through-void

Detects unsafe or redundant two-step casting operations involving `void*`.

Two-step type conversions via `void*` are discouraged for several reasons.

- They obscure code and impede its understandability, complicating maintenance.

- These conversions bypass valuable compiler support, erasing warnings related to pointer alignment. It may violate strict aliasing rule and leading to undefined behavior.

- In scenarios involving multiple inheritance, ambiguity and unexpected outcomes can arise due to the loss of type information, posing runtime issues.

In summary, avoiding two-step type conversions through `void*` ensures clearer code, maintains essential compiler warnings, and prevents ambiguity and potential runtime errors, particularly in complex inheritance scenarios.

Examples:

    using IntegerPointer = int *;
    double *ptr;

    static_cast<IntegerPointer>(static_cast<void *>(ptr)); // WRONG
    reinterpret_cast<IntegerPointer>(reinterpret_cast<void *>(ptr)); // WRONG
    (IntegerPointer)(void *)ptr; // WRONG
    IntegerPointer(static_cast<void *>(ptr)); // WRONG