Can Cauchy principal values of functions with nonsimple poles be evaluated using complex contour integration methods?
In all of the examples I have seen, poles are simple and this helps to avoid those singular points since integrals around them converge to a finite value (such as $i\pi$) when the radius of the circular path around them goes to zero. (In nonsimple poles I guess the integral does not converge around them, on the circle with infinitesimal path.)
For example, for the integral $$\int_{-\infty}^{\infty}\frac{\sin(x)}{x}dx$$ Wolfram alpha (correctly)gives $\pi$ as the principal value, but says $$\int_{-\infty}^{\infty}\frac{\sin(x)}{x^3}dx$$
or
$$\int_{-\infty}^{\infty}\frac{\sin(x)}{x^4}dx$$ do not converge.
The first one is an ordinary improper integral, and Maple says
is $\pi$. The others are, indeed, poles.
This one has a pole of order $1$, and Maple says:
is $0$ as we expect. (And the non-principal-value integral is "undefined".)
This one has a pole of order $2$, and Maple says
is $\infty$.
And for higher integer powers, Maple has alternately $0$ and $\infty$ for the Cauchy principal values.