function
<cmath> <ctgmath>
nanl
float nanl (const char* tagp);
Generate quier NaN (long double)
Returns a quiet NaN (Not-A-Number) value of type long double.
The NaN values are used to identify undefined or non-representable values for floating-point elements, such as the square root of negative numbers or the result of 0/0.
The argument can be used by library implementations to distinguish different NaN values in a implementation-specific manner.
Similarly, nan and nanf return NaN values of type double and float, respectively.
Parameters
- tagp
- An implementation-specific C-string.
If this is an empty string (""), the function returns a generic NaN value (the same as returned by passing "NAN" to strtold).
Return Value
A quiet NaN value.
See also
- NAN
- Not-A-Number (constant)
- nan
- Generate quiet NaN (function)
- isnan
- Is Not-A-Number (macro/function)
- nextafter
- Next representable value (function)
- nexttoward
- Next representable value toward precise value (function)