INFINITY(3) — Linux manual page

INFINITY(3)              Library Functions Manual             INFINITY(3)

NAME         top

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

LIBRARY         top

       Math library (libm)

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.

STANDARDS         top

       C11.

HISTORY         top

       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         top

       fpclassify(3), math_error(7)

COLOPHON         top

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Linux man-pages 6.15            2025-05-17                    INFINITY(3)

Pages that refer to this page: fpclassify(3),  math_error(7)

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