How to judge whether the alpha angle obtained by ProConedataGet is positive or negative

I am using Creo Parametric Release 6.0 and Datecode6.0.6.0

Use the ProConedataGet function to obtain an alpha angle. This angle has positive and negative values. What is the basis for judging positive or negative?

Translated by Simona Cuciureanu using Google Translate on 5.12.2022

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使用ProConedataGet函数可以获得一个alpha角度，这个角度有正值也有负值，判断正负的依据是什么