Re: [Boost-users] Bug when using boost::optional with boost::program_options?

Subject: Re: [Boost-users] Bug when using boost::optional with boost::program_options?
From: Jim Porter (jvp4846_at_[hidden])
Date: 2018-06-05 19:15:47

On 6/5/2018 8:51 AM, Xavier Besseron wrote:
> Dear Jim,
> 
> I remember having some troubles using |boost::optional| with 
> |boost::program_options|.
> I fixed it by adding the following lines:
[snip]

Wow, thanks! I think this is what I needed to get something resolved 
here. I actually did something *very* similar to the code you wrote (I 
think there's a sample of something like this buried in the 
program_options docs somewhere) and totally forgot. Taking a fresh look 
at the compilation error, I see that it passes through this function in 
the middle of the template instantiation stack, so this is almost 
certainly involved in the problem.

Now, why my `validate` function only fails when I'm using MSVC (I tested 
it on VS2017 and it still happens there) with boost::optional (as 
opposed to std::optional) and Boost 1.62+, I'm still not sure. It's 
possible there's still a bug here, but I'll have to continue investigating.

- Jim