nan, nanf, nanl - return quiet NaN
c99 [ flag... ] file... –lm [ library... ] #include <math.h> double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);
The function call nan("n-char-sequence") is equivalent to:
strtod("NAN(n-char-sequence)", (char **) NULL);
The function call nan(" ") is equivalent to:
strtod("NAN()", (char **) NULL)
If tagp does not point to an n-char sequence or an empty string, the function call is equivalent to:
strtod("NAN", (char **) NULL)
Function calls to nanf() and nanl() are equivalent to the corresponding function calls to strtof() and strtold(). See strtod(3C).
These functions return a quiet NaN.
No errors are defined.
See attributes(5) for descriptions of the following attributes:
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