RE: [Boost-Users] function object with lambda

From: Jaakko Jarvi (jajarvi_at_[hidden])
Date: 2003-07-04 13:34:36

In our last exciting episode "Matt Hurd" wrote:

> That was quick. Thanks.

Don't mention. 

> for_each(v.begin(), v.end(), _1 = bind(gen_long));

> Yep, that's how I originally had it. Generates lots of compile errors
> with GCC 3.2 (mingw).

> Any clues? 

There seems to be two things. First, LL can't deduce the return type
of gen_long() call. That is a bit odd, as the class seems to define
result_type, which should be enough. Anyway, that can be fixed with

bind<long>(gen_long)

Then your gen_long is a stateful object, and the operator() is not
defined as const. Lambda functors store all arguments by default
as const copies. You must thus tell the library to store a
reference to your original function object:

bind<long>(ref(gen_long))

var does just as well:

bind<long>(var(gen_long))

  Cheers, Jaakko