Re: [Boost-users] Problem updating code to boost 1.64

Subject: Re: [Boost-users] Problem updating code to boost 1.64
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2017-09-26 01:08:44

On 22/09/2017 03:36, Tim Burgess wrote:
> I have an application that I’m resurrecting. I originally coded it using 
> Visual Studio 2010 with the boost that was current at the time (not sure 
> what version that was). The following line of code used to build fine:
> 
>                  if (CurrentAction[ 0].As <std::wstring>().compare( 
> wstrFunctionName) == 0)
> 
> With my current boost 1.64, I get the following error:
> 
>  >c:\users\tim\projects\surfacereader\screenreaderfunctionsdlg.cpp(146): 
> error C2039: 'As': is not a member of 'boost::any'
> 
> The intent of the code is as follows:
> 
> If CurrentAction[ 0] (which is a boost::any) contains an std::wstring 
> value, compare it to wstrFunctionName.

I don't think that's ever been a supported method of Boost.Any -- 
perhaps you were using a customised version, or some other Any 
implementation?

But the way to extract values from a boost::any is by using any_cast. 
If you want it to throw if the action doesn't contain a wstring:

     if (any_cast<std::wstring>(CurrentAction[0]).compare(...))

If you want it to ignore other types, you'd need something more like:

     auto actionString = any_cast<std::wstring>(&CurrentAction[0]);
     if (actionString && actionString->compare(...))