Can You Use a Lambda In A Class' Initialization List?

Question

I am trying to use a C++11 Lambda to initialize a `const` member variable of a class. A much simplified example: ``` class Foo { public: const int n_; Foo(); }; Foo::Foo() : n_( []() -> int { return 42; } ) { } int main() { Foo f; } ``` In MSVC10 this yields: ``` error C2440: 'initializing' : cannot convert from '`anonymous-namespace'::<lambda0>' to 'const int' ``` In IDEONE this yields: ``` prog.cpp: In constructor 'Foo::Foo()': prog.cpp:9:34: error: invalid conversion from 'int (*)()' to 'int' ``` I'm starting to get the idea that I can't use lambdas in a class' initialization list. Can I? If so, what's the proper syntax?

Accepted Answer

you are trying to convert from a lambda to int - you should call the lambda instead:

```
Foo::Foo()
:   n_( []() -> int { return 42; }() ) //note the () to call the lambda!
{
}
```

Can You Use a Lambda In A Class' Initialization List?

Solution

Problem