c++ lambda size test

lambda_size.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <functional>
+#include <array>
+#include <cstdlib> // for malloc() and free()
+using namespace std;
+
+// replace operator new and delete to log allocations
+void* operator new(std::size_t n)
+{
+    cout << "Allocating " << n << " bytes" << endl;
+    return malloc(n);
+}
+
+void operator delete(void* p) throw()
+{
+    free(p);
+}
+
+class test
+{
+public:
+    std::string s;
+    void a(std::function<void()> & f, const char *str)
+    {
+        auto l = [this, str]() { cout << str << " ? " << s << " from this\n"; };
+        cout << "Assigning lambda3 of size " << sizeof(l) << endl;
+        f = l;
+    }
+};
+
+int main()
+{
+    std::array<char, 16> arr1;
+    auto lambda1 = [arr1](){};
+    cout << "Assigning lambda1 of size " << sizeof(lambda1) << endl;
+    std::function<void()> f1 = lambda1;
+
+    std::array<char, 17> arr2;
+    auto lambda2 = [arr2](){};
+    cout << "Assigning lambda2 of size " << sizeof(lambda2) << endl;
+    std::function<void()> f2 = lambda2;
+
+    test t;
+    std::function<void()> f3;
+    t.s = "str";
+    t.a(f3, "huyambda");
+    f3();
+}