INFINITY(3)                Library Functions Manual                INFINITY(3)

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

LIBRARY
       Math library (libm)

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.

STANDARDS
       C11.

HISTORY
       C99.

       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)

Linux man-pages 6.7               2023-10-31                       INFINITY(3)