From: Richard Smith Date: Mon, 13 May 2013 20:28:15 +0000 (+0000) Subject: Fix a wrong and confusing comment in CharUnits.h. Neither C nor C++ allows X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7e17fdc617ee9db8270f3f6fb4ecd392fed47d80;p=clang Fix a wrong and confusing comment in CharUnits.h. Neither C nor C++ allows bytes and character units to be different sizes. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181730 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/AST/CharUnits.h b/include/clang/AST/CharUnits.h index 082c672c21..09ff6828ef 100644 --- a/include/clang/AST/CharUnits.h +++ b/include/clang/AST/CharUnits.h @@ -19,21 +19,20 @@ #include "llvm/Support/MathExtras.h" namespace clang { - + /// CharUnits - This is an opaque type for sizes expressed in character units. - /// Instances of this type represent a quantity as a multiple of the size + /// Instances of this type represent a quantity as a multiple of the size /// of the standard C type, char, on the target architecture. As an opaque /// type, CharUnits protects you from accidentally combining operations on - /// quantities in bit units and character units. + /// quantities in bit units and character units. + /// + /// In both C and C++, an object of type 'char', 'signed char', or 'unsigned + /// char' occupies exactly one byte, so 'character unit' and 'byte' refer to + /// the same quantity of storage. However, we use the term 'character unit' + /// rather than 'byte' to avoid an implication that a character unit is + /// exactly 8 bits. /// - /// It should be noted that characters and bytes are distinct concepts. Bytes - /// refer to addressable units of data storage on the target machine, and - /// characters are members of a set of elements used for the organization, - /// control, or representation of data. According to C99, bytes are allowed - /// to exceed characters in size, although currently, clang only supports - /// architectures where the two are the same size. - /// - /// For portability, never assume that a target character is 8 bits wide. Use + /// For portability, never assume that a target character is 8 bits wide. Use /// CharUnit values wherever you calculate sizes, offsets, or alignments /// in character units. class CharUnits {