nan

, nanf

, nanl

- return quiet NaN

Synopsis

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double nan(const char *tagp);

float nanf(const char *tagp);

long double nanl(const char *tagp);

Description

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).

Return Values

These functions return a quiet NaN.

Errors

No errors are defined.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

math.h(3HEAD), strtod(3C), attributes(5), standards(5)