How do you allow multiple symbols in VisualStudio? /A On Thu, Aug 26, 2010 at 6:51 PM, Chuck Seberino <[email protected]>wrote:
> Anders, > > It is somewhat relevant to OSG too, in that linking against osgDB and other > code that uses <fstream> will cause similar 'multiple-defined' linker > errors. This problem seems to be only with MSVC2010, the OS doesn't seem to > matter (I use XP). osgDB is affected because of osgDB::fstream, which > subclasses from std::fstream. The current workaround is to allow multiple > symbols when linking. I would be interested in finding a better solution to > this problem... > > Chuck > > > On Aug 26, 2010, at 9:35 AM, Anders Backman wrote: > > Hi all. > > This is not related to OSG in any way, but as there so many experts on the > list, I thought I should take the opportunity to ask this... > > I have a problem related to linking in VS2010. > > Im using VS2010 under Windows 7 (64). > > Im building a large source package which is divided into two separate > libraries (dynamic linking: .lib, .dll). > > in the first library, a.lib we are using both std::stringstream and > std::ostringstream. a.lib depends on other libraries, all built by myself > using CMake and VS2010. CMake defaults to /MD code generation > (MultiThreaded). Im using this consistently over all my libraries (just > double checked to be sure). > > When I build the next library, b.lib, which depends on a.lib, I get the > following linking errors: > > > Linking of b.lib: > > 1>a.lib(a.dll) : error LNK2005: "public: void __thiscall > std::basic_ostringstream<char,struct std::char_traits<char>,class > std::allocator<char> >::`vbase destructor'(void)" > (??_d?$basic_ostringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@@QAEXXZ) > already defined in ImageCapture.obj > > 1>a.lib(a.dll) : error LNK2005: "public: class > std::basic_string<char,struct std::char_traits<char>,class > std::allocator<char> > __thiscall std::basic_ostringstream<char,struct > std::char_traits<char>,class std::allocator<char> >::str(void)const " (?str@ > ?$basic_ostringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@ > @qbe?av?$basic_str...@du?$char_traits@d...@std@@v?$alloca...@d@2@@2...@xz) > already defined in ImageCapture.obj > > 1>a.lib(a.dll) : error LNK2005: "public: __thiscall > std::basic_ostringstream<char,struct std::char_traits<char>,class > std::allocator<char> >::basic_ostringstream<char,struct > std::char_traits<char>,class std::allocator<char> >(int)" > (??0?$basic_ostringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@ > @q...@h@Z) already defined in ImageCapture.obj > > > > Ok, I go into the sourcecode of ImageCapture.cpp and remove the use of > std::ostringstream. > > And everything builds. > > Next, I try to use std::ostringstream in some other cpp file of the b.lib, > so I just copy the code from ImageCapture.cpp into another .cpp file in > b.lib, including the #include directives... > > It links just fine. > > > One important thing to mention, all of this works just fine in VS2008. > > > Next, I tried to change from std::ostringstream to std::stringstream in > both a.lib AND b.lib. > > > Now I get the same error, but instead its std::stringstream mentioned in > the error message: > > > 2>a.lib(a.dll) : error LNK2005: "public: void __thiscall > std::basic_stringstream<char,struct std::char_traits<char>,class > std::allocator<char> >::`vbase destructor'(void)" > (??_d?$basic_stringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@@QAEXXZ) > already defined in ImageCapture.obj > > 2>a.lib(a.dll) : error LNK2005: "public: class > std::basic_string<char,struct std::char_traits<char>,class > std::allocator<char> > __thiscall std::basic_stringstream<char,struct > std::char_traits<char>,class std::allocator<char> >::str(void)const " (?str@ > ?$basic_stringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@ > @qbe?av?$basic_str...@du?$char_traits@d...@std@@v?$alloca...@d@2@@2...@xz) > already defined in ImageCapture.obj > > 2>a.lib(a.dll) : error LNK2005: "public: __thiscall > std::basic_stringstream<char,struct std::char_traits<char>,class > std::allocator<char> >::basic_stringstream<char,struct > std::char_traits<char>,class std::allocator<char> >(int)" > (??0?$basic_stringstr...@du?$char_traits@d...@std@@v?$alloca...@d@2@@std@ > @q...@h@Z) already defined in ImageCapture.obj > > So, the situation is exactly the same, its just changed from > std::ostringstream to std::stringstream. > > If I have just the right balance between stringstream and ostringstream, it > builds. Then the problem occurs when I want to build a third library, > depending on both a.lib AND b.lib... > > Then it starts all over. > > The next thing I did was to generate project files for vs2008, build with > vs2008 (using dependencies built with vs2010), compiles/links just fine. > Except it does not run (incompatible STL, crash in deque). > > Ok, so it builds in VS2008. Next was to build everything in vs2010 using > the same project files. Then I get the above linking error. > > > Im more and more leaning towards a bug in VS2010, but its really hard to > verify... > > Anyone experienced this in VS2010? > - > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > --
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