- Use `.c_str()` sparingly. Its only valid use is to pass C++ strings to C functions that take NULL-terminated

strings.

- Do not use it when passing a sized array (so along with `.size()`). Use `.data()` instead to get a pointer

to the raw data.

- *Rationale*: Although this is guaranteed to be safe starting with C++11, `.data()` communicates the intent better.

- Do not use it when passing strings to `tfm::format`, `strprintf`, `LogPrint[f]`.

- *Rationale*: This is redundant. Tinyformat handles strings.

- Do not use it to convert to `QString`. Use `QString::fromStdString()`.

- *Rationale*: Qt has build-in functionality for converting their string

type from/to C++. No need to roll your own.

- In cases where do you call `.c_str()`, you might want to additionally check that the string does not contain embedded '\0' characters, because

it will (necessarily) truncate the string. This might be used to hide parts of the string from logging or to circumvent

checks. If a use of strings is sensitive to this, take care to check the string for embedded NULL characters first

and reject it if there are any (see `ParsePrechecks` in `strencodings.cpp` for an example).