nan(3C)

NAME
     nan, nanf, nanl - functions that return a quiet NaN

SYNOPSIS
     #include <math.h>

     double nan(const char *tagp);
     float nanf(const char *tagp);
     long double nanl(const char *tagp);

DESCRIPTION
     These routines are not available for programs compiled with the O32 ABI.

     Here tagp is a pointer to a null-terminated character
     sequence composed of alphanumeric characters and underscores (_).
     The call nan("n-char-seq") is equivalent to
     strtod("NAN(n-char-sequence)", (char **) NULL);
     The call nan("") is equivalent to strtod("NAN()", (char **) NULL).
     If tagp does not point to a n-char-sequence or an empty
     string, the call is equivalent to strtod("NAN", (char **) NULL);
     Calls to nanf and nanl are equivalent to the corresponding calls to
     strtof and strtold.

RETURN VALUES
     The nan functions return a quiet NaN;  Current implementation on Irix
     systems ignores the character sequence pointed to by tagp.

SEE ALSO
     math(3M)