Annex C (informative) Compatibility [diff]

Change: pp-number can contain one or more single quotes.

Rationale: Necessary to enable single quotes as digit separators.

Effect on original feature: Valid C++ 2011 code may fail to compile or may change meaning in this International Standard.

For example, the following code is valid both in C++ 2011 and in this International Standard, but the macro invocation produces different outcomes because the single quotes delimit a character-literal in C++ 2011, whereas they are digit separators in this International Standard:

#define M(x, ...) __VA_ARGS__
int x[2] = { M(1'2,3'4, 5) };
// int x[2] = { 5 };      --- C++ 2011
// int x[2] = { 3'4, 5 }; --- this International Standard