F.2.1 Infinities, signed zeros, and NaNs

1

This specification does not define the behavior of signaling NaNs.[1] It generally uses the term NaN to denote quiet NaNs. The NAN and INFINITY macros and the nan functions in <math.h> provide designations for IEC 60559 NaNs and infinities.

Footnotes

[1]

Since NaNs created by IEC 60559 operations are always quiet, quiet NaNs (along with infinities) are sufficient for closure of the arithmetic.