undefined reference to `sqrt'

[DtY]

So I wrote a function to calculate the distance between two points (using Pythagorean theorem), but when I compile it tells me undefined reference to `sqrt'

c:

#include <math.h> static unsigned int distanceBetween(unsigned int x,unsigned int y,unsigned int xx,unsigned int yy) {     double X = x;     double Y = y;     double XX = xx;     double YY = yy;     double result = 0;     result = pow( pow(X-XX, 2.0) + pow(Y-YY, 2.0) ,0.5);     return (int)result; }

I'm guessing that pow() seeing the power as 1/2 calls sqrt, but why wouldn't sqrt be defined?

[Analysis Mode]

I can't really make heads or tails of what it's saying, but here's a link

[DtY]

Oh thanks, seems I have to add -lm to the linker command if I want to use the math library.

Thanks