Determine if a number is finite
#include <math.h> int isfinite ( double x );
The isfinite() macro determines if x is finite.
#include <stdio.h> #include <math.h> int main(int argc, char** argv) { double a, b, c, d; a = 2; b = -0.5; c = NAN; d = 1.0/0.0; printf("%f is %s \n", a, (isfinite(a)) ? "finite" : "not finite"); printf("%f is %s \n", b, (isfinite(b)) ? "finite" : "not finite"); printf("%f is %s \n", c, (isfinite(c)) ? "finite" : "not finite"); printf("%f is %s \n", d, (isfinite(d)) ? "finite" : "not finite"); return(0); }
produces the output:
2.000000 is finite -0.500000 is finite nan is not finite inf is not finite
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |