a) You want to use _1 instead of _2
b) _1/_2 are in namespace boost::lambda
boost::function<float(float)> f = boost::lambda::bind(fx,boost::lambda::_1,2);

It is actually possible to use _2 but then the functor takes to args and ignores the first:
  boost::function<float(float,float)> f = boost::lambda::bind(fx,boost::lambda::_2,2);
 std::cout << f(100,3) << std::endl; // returns 5

cheers

Arnaldur



"Chris Weed" <chrisweed@gmail.com>
Sent by: boost-users-bounces@lists.boost.org

19.10.2006 05:04
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Subject
[Boost-users] [function][lambda] Create a boost function to a bind        functor





Hi,
I would like to create a boost::function to a lambda::bind functor such as

float fx(float a, float b) { return a+b; }

int main()
{
 boost::function<float(float)> f = boost::lambda::bind(fx,_2,2);
 std::cout << f(3) << std::endl;
 return 0;
}

I would expect this to bind 2 to the "b" argument of fx, and print "5".
Instead with msvc-8.0 I get a bunch or compile errors.
Any help would be greatly appreciated.
Chris
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