Technical Reference: Base Operating System and Extensions, Volume 1

nan, nanf, or nanl Subroutine

Purpose

Returns quiet NaN.

Syntax

#include <math.h>

double nan (tagp)
const char *tagp;

float nanf (tagp)
const char *tagp;

long double nanl (tagp)
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.

Parameters

Return Values

The nan, nanf, and nanl subroutines return a quiet NaN with content indicated through tagp.

Related Information

The atof atoff Subroutine.

math.h in AIX 5L Version 5.2 Files Reference.