> gcc, however, always defines FLT_ROUNDS to 1

Well, considering that gcc doesn't support the FENV_ACCESS pragma, and as such all fesetround calls are always UB, it is valid for it to act as if the rounding mode never changes from the default :)

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uecker 2 hours ago | parent [-]

Well, it is not ok to not support FENV_ACCESS though.

	▲	amszmidt 41 minutes ago \| parent [-]
		I skimmed the standard and POSIX, but couldn’t find anything that an implementation is required to support FENV_ACCESS.