nanf

NAN(3)			     libc math functions		       NAN(3)



NAME
       nan, nanf, nanl - return ’Not a Number’

SYNOPSIS
       #include <math.h>

       double nan(const char *tagp);

       float nanf(const char *tagp);

       long double nanl(const char *tagp);

DESCRIPTION
       These  functions	 return	 a  representation  (determined by tagp) of a
       quiet NaN. If the implementation does not support  quiet	 NaNs,	these
       functions return zero.

       The  call  nan("char-sequence")	is  equivalent	to strtod ("NAN(char-
       sequence)",NULL) and similarly calls to nanf and nanl  are  equivalent
       to analogous calls to strtof and strtold.

       The  argument tagp is used in an unspecified manner.  On IEEE 754 sys-
       tems, there are many representations of NaN, and tagp selects one.  On
       other systems it may do nothing.

CONFORMING TO
       C99.  See  also IEC 559 and the appendix with recommended functions in
       IEEE 754/IEEE 854.

SEE ALSO
       isnan(3), strtod(3)



GNU				  2002-08-10			       NAN(3)