F.2 Types
1 The C floating types match the IEC 60559 formats as follows:
The float type matches the IEC 60559 single format.
The double type matches the IEC 60559 double format.
The long double type matches an IEC 60559 extended format,[357]) else a non-IEC 60559 extended format, else the IEC 60559 double format.
Any non-IEC 60559 extended format used for the long double type shall have more precision than IEC 60559 double and at least the range of IEC 60559 double.[358])
Recommended practice
2 The long double type should match an IEC 60559 extended format.
Footnotes
[357] ''Extended'' is IEC 60559's double-extended data format. Extended refers to both the common 80-bit and quadruple 128-bit IEC 60559 formats.
[358] A non-IEC 60559 long double type is required to provide infinity and NaNs, as its values include all double values.