c++ - Using lambda expressions by value capture -

quick query regarding usage of lambda captures, particularly "by value capture". here code:

class carl{ public:     int x;           void sayhi(); };   void carl::sayhi(){      auto c1 = [=](){            //capture value     std::cout<<&x<<std::endl;        x = 10;                     // access copy?     };      c1();     std::cout<<&x<<std::endl;   // same address 1 inside lambda     std::cout<<x<<std::endl;    //prints 10 why???? }  int main(int argc, char** argv) {  carl x; x.sayhi();  return 0; } 

my issue that, "by value" captures in lambda supposed affect original? aren't supposed make copy? example, used [=] lambda make copy of variable within class's scope. tried accessing x , directly altered x's original value. tried researching , own words: it's stated accessing variable inside lambda has [=] capture access lambda's local copy.

edit: feeling trying access this pointer captured [=]. therefore, accessing x code accessing this->x same pointer original one. please correct me if i'm wrong.

when accessing non-static class data members inside lambda, capturing this pointer value , accessing class member this->x. means no local copy of x made. modifying actual x in current object.

if fact, if value captured "by value", copy, attempt modify fail. x = 10 not compile if x captured value. need declare lambda mutable if want able modify captured state.