Returns a Not-a-Number (NaN).

[Classification]

Mathematical library

[Syntax]

#include <math.h>

long double __far nanl(const char __far *tagp); (C99)

[Return value]

Returns a Not-a-Number (NaN).

[Description]

This function is equivalent to strtold("NAN(n character string)", (char __near * __near *)NULL).