NAME
INFINITY, NAN, HUGEVAL, HUGEVALF, HUGEVALL - floating-point con‐ stants SYNOPSIS
#define ISOC99SOURCE /* See featuretestmacros(7) */
#include
INFINITY NAN HUGEVAL HUGEVALF HUGEVALL 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 sig‐ naling NaN. See IEC 60559:1989. The macros HUGEVAL, HUGEVALF, HUGEVALL expand to constants of types double, float and long double, respectively, that represent a large positive value, possibly plus infinity. CONFORMING TO C99. AVAILABILITY On a glibc system, the macro HUGEVAL is always available. Availabil‐
ity of the NAN macro can be tested using #ifdef NAN, and similarly for INFINITY, HUGEVALF, HUGEVALL. They will be defined by
if ISOC99SOURCE or GNUSOURCE is defined, or STDCVERSION is defined and has a value not less than 199901L. SEE ALSO fpclassify(3), matherror(7) COLOPHON This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2007-07-26 INFINITY(3)