Why is the size of a lambda 1 in C++?

I am working with the memory of some lambdas in C++, but I am a bit puzzled by their size.

Here is my test code:

#include <iostream>
#include <string>

int main()
{
  auto f = [](){ return 17; };
  std::cout << f() << std::endl;
  std::cout << &f << std::endl;
  std::cout << sizeof(f) << std::endl;
}

You can run it here: http://cpp.sh/72zk

The ouptut is:

17
0x7d90ba8f626f
1

This suggests that the size of my lambda is 1.

• How is this possible?

• Shouldn't the lambda be, at minimum, a pointer to its implementation?