Index: llvm/trunk/docs/CodingStandards.rst =================================================================== --- llvm/trunk/docs/CodingStandards.rst +++ llvm/trunk/docs/CodingStandards.rst @@ -305,6 +305,21 @@ #. When writing a source file that is used by a tool that only accepts C style comments. +#. When documenting the significance of constants used as actual parameters in + a call. This is most helpful for ``bool`` parameters, or passing ``0`` or + ``nullptr``. Typically you add the formal parameter name, which ought to be + meaningful. For example, it's not clear what the parameter means in this call: + + .. code-block:: c++ + + Object.emitName(nullptr); + + An in-line C-style comment makes the intent obvious: + + .. code-block:: c++ + + Object.emitName(/*Prefix=*/nullptr); + Commenting out large blocks of code is discouraged, but if you really have to do this (for documentation purposes or as a suggestion for debug printing), use ``#if 0`` and ``#endif``. These nest properly and are better behaved in general