Generate quiet NaN.
The call nan("n-char-sequence") is equivalent to strtod("NAN(n-charsequence)", (char**) NULL); the call nan("") is equivalent to strtod("NAN()", (char**) NULL). If tagp does not point to an n-char sequence or an empty string, the call is equivalent to strtod("NAN", (char**) NULL). Calls to nanf and nanl are equivalent to the corresponding calls to strtof and strtold.
- Parameters
-
arg | Narrow character string identifying the contents of a NaN. |
- Returns
- The nanl functions return a quiet NaN, if available, with content indicated through tagp. If the implementation does not support quiet NaNs, the functions return zero.