Edit: check for me whether just calling lrint(x) works. The manpage doesn't specify that lrint() will set FE_INEXACT, but it seems weird to me that it wouldn't.
Great, thanks, now I have to go back and restart some of those code reviews I've been doing of certain third party matrix math libraries...
Annex F:
The lrint and llrint functions provide floating-to-integer conversion as prescribed by IEC 60559. They round according to the current rounding direction. If the rounded value is outside the range of the return type, the numeric result is unspecified and the ''invalid'' floating-point exception is raised. When they raise no other floating-point exception and the result differs from the argument, they raise the ''inexact'' floating-point exception.
> The floating-point environment has thread storage duration. The initial state for a thread's floating-point environment is the current state of the floating-point environment of the thread that creates it at the time of creation.