Re: [Boost-build] missing symbolic link during build

Subject: Re: [Boost-build] missing symbolic link during build
From: Stefan Seefeld (stefan_at_[hidden])
Date: 2017-01-24 00:54:18

On 23.01.2017 20:34, Steven Watanabe wrote:
> AMDG
>
> On 01/23/2017 01:49 PM, Stefan Seefeld wrote:
>> I'm running into a build failure that I'm not fully understand, so let
>> me describe what I ended up in this situation:
>>
>>
>> I'm working on a Linux machine, using a full (modular) boost repo. I
>> have started a Windows VM and mounted the directory containing the repo
>> there.
>>
>   This can be a bit tricky depending on the details.
> In particular, if the host and the VM don't agree
> about whether they can create symbolic links, then
> you need to make sure that all the links are always
> created from the host side.  Before I build in a VM,
> I always run `b2 headers` on the host first.

OK, that worked, thanks.
>> When I'm running b2 on Windows, I eventually get the error
>>
>>   .\boost/preprocessor/iteration/detail/iter/forward1.hpp(47): fatal
>> error C1083: Cannot open include file:
>> 'boost/utility/detail/result_of_iterate.hpp': No such file or directory
>>
>> I see that everything inside boost/utility/ is a symbolic link to
>> libs/utility/include/... However, the 'boost/utility/detail/' directory
>> is missing there, leading to the above error.
>>
>>
>> Any idea how that could happen ? Speculating: is it possible that on
>> Linux that link isn't needed, so is left out (after all, I'm able to
>> build on Linux without errors), but on Windows the link is needed, but
>> b2 discovered that (some) links already existed, and thus skipped that
>> build step ?
>>
>
> It's probably missing because it isn't found by the #include scanner.
> (the easiest way to fix this is to add
> #if 0
> #include <boost/utility/detail/result_of_iterate.hpp>
> #endif
> in result_of.hpp.

What project do these files belong to, i.e. where should I report this
as a bug ?
>> How can I clean up my (source) tree, i.e. remove the links, so that
>> running b2 would be forced to regenerate them ?
>>
>   You can just run `b2 headers` at the root of
> the boost tree to generate all links.  You don't
> need to delete the existing links first.

What if I want to reproduce the original (i.e., pristine) state of the
source tree ? Do I have to remove the links manually ?
>> And, to step back a step: why are these links generated to begin with ?
>> Can't they be avoided by adding a bunch of include paths ? (I'd argue
>> that using explicit include paths is better as it helps the
>> modularization effort.)
>>
> a) This is almost guaranteed to overrun command line length
>    limitations, if you're not using rsp files.
> b) It makes manual compiler invocation for users of boost
>    incredibly annoying.  (It would essentially be impractical
>    to invoke the compiler without using some tool to determine
>    all the correct #include paths.)

It sounds like you have given up on the Boost modularization effort.

        Stefan

-- 
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