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| -rw-r--r-- | doc/developer-notes.md | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/doc/developer-notes.md b/doc/developer-notes.md index 9cf4b4b075..1a7ce91ca6 100644 --- a/doc/developer-notes.md +++ b/doc/developer-notes.md @@ -640,6 +640,28 @@ Strings and formatting - *Rationale*: Bitcoin Core uses tinyformat, which is type safe. Leave them out to avoid confusion. +- 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). + Shadowing -------------- |