NAME

       INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL - floating-point constants

SYNOPSIS

       #define _ISOC99_SOURCE      /* See feature_test_macros(7) */
       #include <math.h>

       INFINITY

       NAN

       HUGE_VAL
       HUGE_VALF
       HUGE_VALL

DESCRIPTION

       The macro INFINITY expands to a float constant representing positive infinity.

       The  macro  NAN  expands to a float constant representing a quiet NaN (when supported).  A quiet NaN is a
       NaN ("not-a-number") that does not raise exceptions when it is used in arithmetic.   The  opposite  is  a
       signaling NaN.  See IEC 60559:1989.

       The  macros  HUGE_VAL,  HUGE_VALF,  HUGE_VALL expand to constants of types double, float and long double,
       respectively, that represent a large positive value, possibly positive infinity.

CONFORMING TO

       C99.

AVAILABILITY

       On a glibc system, the macro HUGE_VAL is always available.  Availability of the NAN macro can  be  tested
       using  #ifdef NAN, and similarly for INFINITY, HUGE_VALF, HUGE_VALL.  They will be defined by <math.h> if
       _ISOC99_SOURCE or _GNU_SOURCE is defined, or __STDC_VERSION__ is defined and has a value  not  less  than
       199901L.

SEE ALSO

       fpclassify(3), math_error(7)

COLOPHON

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                                                   2017-09-15                                        INFINITY(3)