[Boost-bugs] [Boost C++ Libraries] #6642: Windows: auto_link.hpp incorrectly hardstops with error "Mixing a dll boost library with a static runtime is a really bad idea..."

Subject: [Boost-bugs] [Boost C++ Libraries] #6642: Windows: auto_link.hpp incorrectly hardstops with error "Mixing a dll boost library with a static runtime is a really bad idea..."
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-03-01 22:59:14

#6642: Windows: auto_link.hpp incorrectly hardstops with error "Mixing a dll boost
library with a static runtime is a really bad idea..."
--------------------------------+-------------------------------------------
 Reporter:  noloader@…          |       Owner:  johnmaddock
     Type:  Bugs                |      Status:  new        
Milestone:  To Be Determined    |   Component:  config     
  Version:  Boost 1.49.0        |    Severity:  Problem    
 Keywords:                      |  
--------------------------------+-------------------------------------------
 I'm building a DLL which uses *STATIC* runtime linking. This means I am
 using the /MT switch, which defines "_MT" . Since I am building a DLL,
 "_WINDLL" is defined.

 According to "/MD, /MT, /LD (Use Run-Time Library)",
 http://msdn.microsoft.com/en-US/library/2kzt1wy3(v=vs.90).aspx:

 /MT - Causes your application to use the multithread, static version of
 the run-time library. Defines _MT and causes the compiler to place the
 library name LIBCMT.lib into the .obj file so that the linker will use
 LIBCMT.lib to resolve external symbols.

 /MD - Causes your application to use the multithread- and DLL-specific
 version of the run-time library. Defines _MT and _DLL and causes the
 compiler to place the library name MSVCRT.lib into the .obj file.
 Applications compiled with this option are statically linked to
 MSVCRT.lib. This library provides a layer of code that allows the linker
 to resolve external references. The actual working code is contained in
 MSVCR90.DLL, which must be available at run time to applications linked
 with MSVCRT.lib.

 From the documentation, "_MT" is always defined, regardless of whether
 using static or dynamic runtime libraries). "_DLL" is defined when using
 dynamic runtime libraries.

 Somehow, Boost is auto-configuring itself as if "_DLL" was defined in my
 dynamic link library (which it is not).

 Perhaps the following would be a better test (sorry, I could not figure
 out the Boost specific stuff):

 #if defined(BOOST_OS_WINDOWS) && defined(_MT) && !defined(_DLL)
 # define BOOST_OS_WINDOWS_STATIC 1
 #elif defined(BOOST_OS_WINDOWS) && defined(_MT) && defined(_DLL)
 # define BOOST_OS_WINDOWS_DYNAMIC 1
 #elif defined(BOOST_OS_WINDOWS)
 # pragma warning("Neither static nor dynamic runtime linking has been
 picked up")
 #endif

 Note that the above does not touch upon DLL's and Import/Export headers -
 just the static and dynamic linking to the runtime

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6642>
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