IntegralCauchy GSL Error

ROOT
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Hi,
I need to perform a Cauchy Integral. I have attached a simplified version of the macro I am using that reproduces the problem and the Mathematica notebook used for cross-check.
The function to be integrated contains the term x^(alpha). When alpha has a positive sign (alpha = 0.3) I get the integral equal to -1.7877, which agrees with the analogous Mathematica code.
On the other hand, when alpha is negative (alpha = -0.3) I get the following error:
Error in : Error 5 in qawc.c at 217 : could not integrate function
However, the Mathematica code computes the Cauchy Integral with the negative alpha without errors and the output is equal to -1.82904
My physics analysis requires alpha = -0.3 which does not work in my ROOT code.
I appreciate any help to get the same result achieved by the Mathematical numerical integration when alpha = -0.3.

Many Thanks
CauchyIntegral.zip (2.1 KB)

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double value = ig.IntegralCauchy(1.e-307, 1., xi);

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Highly appreciated. Many thanks for your help and your quick reply! There is no error now and it agrees with the value obtained in Mathematica.

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