Re: [boost] [lambda] Can't get simple lambda working...

Subject: Re: [boost] [lambda] Can't get simple lambda working...
From: Eric Niebler (eric_at_[hidden])
Date: 2012-03-19 19:05:24

On 3/19/2012 3:44 PM, Robert Dailey wrote:
> Here is a basic function I have:
> 
> 
> bool MimeDocument::GetExistingAttachment(
>     std::string const& filename,
>     std::vector<MessageAttachment> const& attachments,
>     MessageAttachment& attachment
> )
> {
>     using namespace boost::lambda;
>     using boost::lambda::_1;
> 
>     std::vector<MessageAttachment>::const_iterator it =
>         std::find_if( attachments.begin(), attachments.end(),
>             bind( &MessageAttachment::name, _1 ) == filename
>         );
> 
>     if( it != attachments.end() ) {
>         attachment = *it;
>         return true;
>     }
> 
>     return false;
> }
> 
> MessageAttachment::name() has 2 overloads, one that takes 1 parameter and
> the other that takes no parameter. I'm attempting to call the version that
> accepts no parameters and returns a "char const*". I want to then compare
> this value to the local variable "filename".
<snip>

If a function is overloaded, you have to help the compiler choose the
right overload when you take the function's address. So replace &
MessageAttachment::name with something like:

  static_cast< char const* (MessageAttachment::*)() >(
&MessageAttachment::name )

Hope I got the syntax right.

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com