C++ how to return a const object from a class variable -

so have class called musiccomposer has audiosignal object data member called music. music non-const. however, need return music const audiosignal in method called getmusic.

in source file:

const audiosignal& musiccomposer::getmusic(){  } 

music declared as:

audiosignal music; 

^ in header file.

i declare music non-const because music needs changed before returned getmusic method. however, can't figure out life of me how return const version of it. how can return const version of music?

c++ can automatically change mutable const whenever. no biggie. it's going other way that's hard.

return music; 

if really want explicit this, it's wierd code, , wierd bad.

return static_cast<const audiosignal&>(music); 

also, cyber observed getter methods const, lets them called when musiccomposer const.

const audiosignal& musiccomposer::getmusic() const {                                              ^^^^^