1INFINITY(3)                Linux Programmer's Manual               INFINITY(3)
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NAME

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

10       #define _ISOC99_SOURCE      /* See feature_test_macros(7) */
11       #include <math.h>
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13       INFINITY
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15       NAN
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17       HUGE_VAL
18       HUGE_VALF
19       HUGE_VALL
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DESCRIPTION

22       The macro INFINITY expands to a float  constant  representing  positive
23       infinity.
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25       The  macro  NAN  expands  to  a float constant representing a quiet NaN
26       (when supported).  A quiet NaN is a NaN ("not-a-number") that does  not
27       raise exceptions when it is used in arithmetic.  The opposite is a sig‐
28       naling NaN.  See IEC 60559:1989.
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30       The macros HUGE_VAL, HUGE_VALF, HUGE_VALL expand to constants of  types
31       double,  float  and  long  double, respectively, that represent a large
32       positive value, possibly plus infinity.
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CONFORMING TO

35       C99.
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AVAILABILITY

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

45       fpclassify(3), math_error(7)
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COLOPHON

48       This page is part of release 3.53 of the Linux  man-pages  project.   A
49       description  of  the project, and information about reporting bugs, can
50       be found at http://www.kernel.org/doc/man-pages/.
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54                                  2007-07-26                       INFINITY(3)