What is Lambda Capture?

What is Lambda Capture?

Before looking into *this capture, let’s see how lambda capture works in C++. In C++, lambdas are a way to create anonymous functions, which can capture variables from their enclosing scope. There are two primary capture modes: by value and by reference....

Capturing *this in C++ 17

Earlier, we could only capture this pointer by reference. This leads to problems when the referenced object is temporary or goes out of scope leading to the dangling reference. The capture of *this by value was added in C++ 17 to avoid these problems....

Syntax

We just have to define the capture clause of lambda expression like this:...

Example

C++ // C++ Program to illustrate by value capture of *this // in lambda expressions #include using namespace std;    class Counter { public:     Counter()         : count(0)     {     }        void Increment()     {         // Define a lambda that captures *this by value         auto incrementLambda = [*this]() mutable {             // Access the count member variable and             // increment it             count++;         };            // Call the lambda to perform the increment         incrementLambda();     }        int GetCount() const { return count; }    private:     int count; };    int main() {     // Create an instance of the Counter class     Counter counter;        // Call the Increment method, which uses a lambda to     // increment the count     counter.Increment();     counter.Increment();        // Retrieve and print the updated count     cout << "Count: " << counter.GetCount() << endl;        return 0; }...