3.0 KiB
[diff.cpp03.lex]
Annex C (informative) Compatibility [diff]
C.6 C++ and ISO C++ 2003 [diff.cpp03]
C.6.2 [lex]: lexical conventions [diff.cpp03.lex]
Affected subclause: [lex.pptoken]
Change: New kinds of string-literals.
Rationale: Required for new features.
Effect on original feature: Valid C++ 2003 code may fail to compile or produce different results in this revision of C++.
Specifically, macros named R, u8,u8R, u, uR, U, UR, or LR will not be expanded when adjacent to a string-literal but will be interpreted as part of the string-literal.
[Example 1: #define u8 "abc"const char* s = u8"def"; // Previously "abcdef", now "def" â end example]
Affected subclause: [lex.pptoken]
Change: User-defined literal string support.
Rationale: Required for new features.
Effect on original feature: Valid C++ 2003 code may fail to compile or produce different results in this revision of C++.
[Example 2: #define _x "there""hello"_x // #1
Previously, #1 would have consisted of two separate preprocessing tokens and the macro _x would have been expanded.
In this revision of C++, #1 consists of a single preprocessing token, so the macro is not expanded.
â end example]
Affected subclause: [lex.key]
Change: New keywords.
Rationale: Required for new features.
Effect on original feature: Added to Table 5, the following identifiers are new keywords:alignas,alignof,char16_t,char32_t,constexpr,decltype,noexcept,nullptr,static_assert, andthread_local.
Valid C++ 2003 code using these identifiers is invalid in this revision of C++.
Affected subclause: [lex.icon]
Change: Type of integer literals.
Rationale: C99 compatibility.
Effect on original feature: Certain integer literals larger than can be represented by long could change from an unsigned integer type to signed long long.