CriticalSection compiler error


#1

Hello,
can someone help me please with this:

In my class ResoFilter1, I define this:

and I have to admit I don’t exactly know its purpose, but roughly.
I get these compiler errors.

/Users/helmholm/Proj_cpp/m_AudioDemo/app/Builds/MacOSX/…/…/Source/…/JuceLibraryCode/…/…/juce_amalgamated.h: In copy constructor ‘ResoFilter1::ResoFilter1(const ResoFilter1&)’:
/Users/helmholm/Proj_cpp/m_AudioDemo/app/Builds/MacOSX/…/…/Source/…/JuceLibraryCode/…/…/juce_amalgamated.h:4188: error: ‘juce::CriticalSection::CriticalSection(const juce::CriticalSection&)’ is private
/Users/helmholm/Proj_cpp/m_AudioDemo/app/Builds/MacOSX/…/…/Source/dsp/ResoFilter1.h:12: error: within this context
/Users/helmholm/Proj_cpp/m_AudioDemo/app/Builds/MacOSX/…/…/Source/modules/ResoFilterAudioSource.cpp: In member function ‘virtual void ResoFilterAudioSource::getNextAudioBlock(const juce::AudioSourceChannelInfo&)’:
/Users/helmholm/Proj_cpp/m_AudioDemo/app/Builds/MacOSX/…/…/Source/modules/ResoFilterAudioSource.cpp:62: note: synthesized method ‘ResoFilter1::ResoFilter1(const ResoFilter1&)’ first required here

And if I do what the last line is saying - defining and declaring this function:
ResoFilter1::ResoFilter1(const ResoFilter1&)

the error disappears.
Can anybody please give some information what this ResoFilter1::ResoFilter1(const ResoFilter1&) is needed for?
Thanks a lot
chris