我刚将一个结构移到另一个子项目的一部分的类中。那些已经通过以下方式成功连接的项目：
ScipioAI-Mind.pro：
INCLUDEPATH += $$PWD/../ScipioAI-core //the project which provides the class with struct
在执行此操作之前，它肯定可以正常工作，但是现在出现以下错误：
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `auxalary::FadeObj<int>::FadeObj(bool, int)'
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `operator==(auxalary::FadeObj<bool>, auxalary::FadeObj<bool>)'
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `operator==(auxalary::FadeObj<int>, auxalary::FadeObj<int>)'
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `auxalary::FadeObj<char>::FadeObj(bool, char)'
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `operator==(auxalary::FadeObj<char>, auxalary::FadeObj<char>)'
/usr/bin/ld: /root/Desktop/SCIEBO/C++/ScipioAI/build-ScipioAI-core-Desktop-Debug/ScipioAI-Console/../ScipioAI-Mind//libScipioAI-Mind.so: undefined reference to `auxalary::FadeObj<bool>::FadeObj(bool, bool)'
FadeObj是结构，辅助是包含它的类。
auxalary在核心项目中，而之前包含fadeobj的类在-mind项目中。
即使阅读了一些有关undefined reference错误的信息，我也不知道在哪里寻找哪种错误。 ：/