c++ - Is it possible to find the number/type of the captured variables in a lambda? -

is possible automatically realize number of variables captured lambda when accessed value or reference? possible decipher types? example, assume piece of code:

int = 47; int b = 48; long long c = 49; auto f1 = [=](){ return + b; }; auto f2 = [=](){ return + b + c; }; 

is possible have function named count_args returns 2 in line , 3 in next line if called below?

std::cout << count_args( f1 ) << "\n" << count_args( f2 ); 

no, because question implicitly assumes captured variables in fact member variables. compiler granted far more latitude. ajay notes in comments, decent optimizer can replace members hoisted expressions, , may alter types, use non-c++ types, etcetera. may capture struct color { char r,g,b } while lambda stores .r , .g only. count_args 2/3rd ?