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A capture clause of lambda definition is used to specify which variables are captured and whether they are captured by reference or by value. An empty capture closure [ ], indicates that no variables are used by lambda which means it can only access variables that are local to it.
Much like functions can change the value of arguments passed by reference, we can also capture variables by reference to allow our lambda to affect the value of the argument. To capture a variable by reference, we prepend an ampersand ( & ) to the variable name in the capture.
To capture the member variables inside lambda function, capture the “this” pointer by value i.e. std::for_each(vec. begin(), vec. end(), [this](int element){ //.... }
The C++ Capture activity allows you to export an application frame as C++ code to be compiled and run as a self-contained application for later analysis, debugging, profiling, regression testing, and edit-and-compile experimentation (see Save a Capture with Source Code Generation for more information).
AFAIK, C++11/14 does not allow in-place definition of a new return type while defining a lambda. However, it seems a C++14 lambda capture expression essentially creates an anonymous type with one or more "members" and an operator (). So, why is that the compiler does not allow access to the captured members from outside the lambda. My feeble mind cannot handle the complexities of C++ but does it sound like a reasonable language extension to you? Here is an example.
vector<string> words = { "Stack", "Overflow" };
auto l = [w = words](){}; // almost like a C# anonymous type
cout << l.w[0]; // does not work.
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