On Mon, 17 Oct 2022, Jonathan Wakely via Gcc-patches wrote: > > And I/O etc. support is missing, not sure I'm able to handle that and if it > > is e.g. possible to keep that support out of libstdc++.so.6, because what > > extended floating point types one has on a particular arch could change over > > time (I mean e.g. bfloat16_t support or float16_t support can be added > > etc.). > > Yes, I think we can add the I/O functions as always_inline because all > they're going to do is convert the argument to float, double, or long > double and then call the existing overloads. There will be no new > virtual functions.
As with fma, note that doing conversions from strings to floating-point is a case where doing the operation on float and then narrowing is technically incorrect because double rounding can occur (the rounded float result can be half way between two values of the narrower type, without that being the exact mathematical result) but the operation should be correctly rounding. It's fine to use float or double operations in the other direction (floating-point to strings), of course. -- Joseph S. Myers jos...@codesourcery.com
