[boost] Re: Re: [thread] Why is there a restriction for the runtimelibraries?

From: Michael Glassford (glassfordm_at_[hidden])
Date: 2004-12-06 15:05:23

"Roland Schwarz" <roland.schwarz_at_[hidden]> wrote in message 
news:41B45B95.8020909_at_chello.at...
> Stefan Slapeta wrote:
>
>> b)
>>
>> thread/detail/config.hpp:
>>
>> #       if defined(BOOST_MSVC) || defined(BOOST_INTEL_WIN)
>>             //For VC++, choose according to threading library 
>> setting
>> #           if defined(_DLL)
>>                 //Threading library is dll: use Boost.Threads dll
>> #               define BOOST_THREAD_USE_DLL
>> #               define BOOST_THREAD_DECL __declspec(dllimport)
>> #               define BOOST_DYN_LINK
>> #           else
>>                 //Threading library is lib: used Boost.Threads lib
>> #               define BOOST_THREAD_USE_LIB
>> #               define BOOST_THREAD_DECL
>> #           endif
>> #       else
>>
>> IMO this sequence is wrong (look at the comments!) because the _DLL 
>> macro _DOESN'T_ say that a dll is built!!!! It rather says that a 
>> shared runtime is used (I don't know if this was the intention 
>> behind this sequence, the comment is wrong anyway).

Depends how you read the comment. By "threading library" above I meant 
the VC++ threading library, part of the VC++ runtime library. I can 
certainly change the comments (as suggested below) to make this 
clearer.

>> The code as is means that every static rt configuration is linked 
>> to a static boost.thread lib and every dynamic rt configuration is 
>> linked to boost.thread as dll. I just don't know if there is any 
>> rationale behind automatically selecting these combinations.
>>
> I think the problem is of how to deduce how the boost libs should be 
> linked in when the user does not explicitely
> specifiy e.g. BOOST_USE_LIB.
> A reasonable default in this case would be then to link in the 
> library corresponding to the RTL choice.

This was my intention when I wrote the above.

> The code snippet refers to the default choice doesn't it?

Yes, it chooses a default that can be overridden by #defining 
BOOST_THREAD_USE_LIB or BOOST_THREAD_USE_DLL

> #   else //Use default
> The comment
>            //For VC++, choose according to threading library setting
> should better read
>            //For VC++, choose according to C-runtime library setting
> of course.
>
> Does this make sense?
>
> Roland

Yes.

Mike