Comment by dzaima

A C implementation can be fully-compliant without conforming to ISO/IEC 6055, that's optional; question is just whether that optionality extends to fenv.h too. (at least how far I looked, imo it doesn't, and the pragma must exist, and valid fesetround calls (which there may be none of if no FE_* rounding modes are defined) must be represented by FLT_ROUNDS, even if it changes literally no actual float op behavior)