https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78696
--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- The radix character is not a POSIX extension. See the C11 7.1.1#2: "The decimal-point character is the character used by functions that convert floating-point numbers to or from character sequences to denote the beginning of the fractional part of such character sequences. 180) It is represented in the text and examples by a period, but may be changed by the setlocale function." (that wording dates back to C90). It's grouping, indicated by the ' flag, that's a POSIX extension. I tend to agree that this option is not yet ready to enable by default. It also risks introducing buffer overruns on systems where printf doesn't quite follow the standard interpretation followed by the implementation of the option. (E.g. some versions of Windows printf functions always use a 3-digit exponent even when standard C would require a 2-digit exponent. Do you allow for that?)
