Make Signalling NaN
Creates a signalling NaN of the specified precision, with a positive sign and zero payload.
_Decimal32 __d32_sNan (void); _Decimal64 __d64_sNaN (void); _Decimal128 __d128_sNaN (void);
_Decimal32 __d32_sNan (void);
_Decimal64 __d64_sNaN (void);
_Decimal128 __d128_sNaN (void);