Section: Linux Programmer's Manual (3)
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INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL - floating point constants
expands to a float constant representing positive infinity.
expands to a float constant representing a quiet NaN
(when supported). A
NaN is a NaN ("not-a-number") that does not raise exceptions
when it is used in arithmetic. The opposite is a
NaN. See IEC 60559:1989.
expand to constants of types double, float and long double, respectively,
that represent a large positive value, possibly plus infinity.
On a glibc system, the macro HUGE_VAL is always available.
Availability of the NAN macro can be tested using
and similarly for INFINITY, HUGE_VALF, HUGE_VALL.
They will be defined by
if _ISOC99_SOURCE or _GNU_SOURCE is defined, or __STDC_VERSION__ is defined
and has a value not less than 199901L.
- CONFORMING TO
- SEE ALSO
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