NAME | SYNOPSIS | DESCRIPTION | CONFORMING TO | AVAILABILITY | SEE ALSO | COLOPHON

INFINITY(3)               Linux Programmer's Manual              INFINITY(3)

NAME         top

       INFINITY,  NAN,  HUGE_VAL, HUGE_VALF, HUGE_VALL - floating-point con‐
       stants

SYNOPSIS         top

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

       INFINITY

       NAN

       HUGE_VAL
       HUGE_VALF
       HUGE_VALL

DESCRIPTION         top

       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         top

       C99.

AVAILABILITY         top

       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         top

       fpclassify(3), math_error(7)

COLOPHON         top

       This page is part of release 4.08 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

                                 2007-07-26                      INFINITY(3)