NAN(2) System Calls Manual NAN(2)
NAME
NaN, Inf, isNaN, isInf - not-a-number and infinity functions
SYNOPSIS
#include <u.h>
#include <libc.h>
double NaN(void)
long Inf(int)
int isNaN(double)
int isInf(double, int)
DESCRIPTION
The IEEE floating point standard defines values called `not-a-number' and positive and negative `infinity'. These values can be produced
by such things as overflow and division by zero. Also, the library functions sometimes return them when the arguments are not in the
domain, or the result is out of range.
NaN returns a double that is not-a-number. IsNaN returns true if its argument is not-a-number.
Inf(i) returns positive infinity if i is greater than or equal to zero, else negative infinity. IsInf returns true if its first argument
is infinity with the same sign as the second argument.
SOURCE
/sys/src/libc/$objtype/nan.c
NAN(2)