Hello,
I was writing and running some tests for a project that uses log4cxx and
some other third party libraries, and received the following linking
errors upon adding the line
::std::deque<::std::string> textSnippets;
to my testing header file (the errors go away if I comment it out):
4>Linking...
4>LINK :
C:\projects\pathfinders\cpp\utilities\projects\lib\Debug\ApplicationUtil
ities_Tests.exe not found or not built by the last incremental link;
performing full link
4>ApplicationUtilities.lib(log4cxx.dll) : error LNK2005: "public: void
__thiscall std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > >::destroy(class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > *)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$allocato
[EMAIL PROTECTED]@2@@std@@@std@@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$alloca
[EMAIL PROTECTED]@2@@2@@Z) already defined in ApplicationUtilities_Tests.obj
4>ApplicationUtilities.lib(log4cxx.dll) : error LNK2005: "protected:
__thiscall std::_Container_base_aux_alloc_empty<class
std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > >
>::~_Container_base_aux_alloc_empty<class std::allocator<class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > > >(void)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]
[EMAIL PROTECTED]@std@@[EMAIL PROTECTED]@2@@std@@@std@@@std@@[EMAIL PROTECTED])
already
defined in ApplicationUtilities_Tests.obj
4>ApplicationUtilities.lib(log4cxx.dll) : error LNK2005: "public: void
__thiscall std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > >::deallocate(class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > *,unsigned int)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$alloc
[EMAIL PROTECTED]@2@@std@@@std@@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$all
[EMAIL PROTECTED]@2@@[EMAIL PROTECTED]@Z) already defined in
ApplicationUtilities_Tests.obj
4>C:\projects\pathfinders\cpp\utilities\projects\lib\Debug\ApplicationUt
ilities_Tests.exe : fatal error LNK1169: one or more multiply defined
symbols found
General online help concerning LNK2005 errors associated with the
standard template library suggests checking that all of the runtime
libraries (under Properties->C++->Code Generation) in all dependencies
are identical. So I did that, and they all seem to be set identically
to Multi-threaded Debug DLL (/MDd) (in the debug versions). That
includes my log4cxx and other third-party builds.
I therefore tried to isolate the problem by creating a small project
that reproduces the errors. I didn't quite succeed, but I did get the
following warnings, which seem very similar to the LNK2005 errors above,
from a simple library that uses log4cxx.lib and deque<string>:
1>------ Rebuild All started: Project: StdLibLinkingBug, Configuration:
Debug Win32 ------
1>Deleting intermediate and output files for project 'StdLibLinkingBug',
configuration 'Debug|Win32'
1>Compiling...
1>StdLibLinkingBug.cpp
1>Creating library...
1>StdLibLinkingBug.obj : warning LNK4006: "protected: __thiscall
std::_Container_base_aux_alloc_empty<class std::allocator<class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > > >::~_Container_base_aux_alloc_empty<class
std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > > >(void)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]
[EMAIL PROTECTED]@std@@[EMAIL PROTECTED]@2@@std@@@std@@@std@@[EMAIL PROTECTED])
already
defined in log4cxx.lib(log4cxx.dll); second definition ignored
1>StdLibLinkingBug.obj : warning LNK4006: "public: void __thiscall
std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > >::deallocate(class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > *,unsigned int)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$alloc
[EMAIL PROTECTED]@2@@std@@@std@@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$all
[EMAIL PROTECTED]@2@@[EMAIL PROTECTED]@Z) already defined in
log4cxx.lib(log4cxx.dll); second
definition ignored
1>StdLibLinkingBug.obj : warning LNK4006: "public: void __thiscall
std::allocator<class std::basic_string<char,struct
std::char_traits<char>,class std::allocator<char> > >::destroy(class
std::basic_string<char,struct std::char_traits<char>,class
std::allocator<char> > *)"
([EMAIL PROTECTED]@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$allocato
[EMAIL PROTECTED]@2@@std@@@std@@[EMAIL PROTECTED]@[EMAIL PROTECTED]@@V?$alloca
[EMAIL PROTECTED]@2@@2@@Z) already defined in log4cxx.lib(log4cxx.dll); second
definition ignored
1>Build log was saved at
"file://c:\projects\pathfinders\cpp\utilities\projects\debugging\StdLibL
inkingBug\Debug\BuildLog.htm"
1>StdLibLinkingBug - 0 error(s), 3 warning(s)
========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========
Since writing similar small programs with the other third party
libraries I'm using did not produce anything similar to the LNK2005
errors, I am guessing that log4cxx is the culprit.
Other (possibly) useful information:
- the warnings and errors do not go away if I replace
deque<string> with vector<string>, but they do go away if I replace
deque<string> with deque<int>
- the original problem cropped up in a series of dependent
static library projects that were finally linked into a .exe. Basically
the situation is something like (where x -> y means y uses or is
dependent on x):
log4cxx -> lib1 (log4cxx wrapper for outputing log messages) -> lib2 ->
lib3 (which declares a deque<string> and configures log4cxx loggers);
lib2 and lib3 -> exe (which gives linking errors when it declares a
deque<string>)
- the code for the small library that produced the LNK4006
warnings follows. The .vsproj file lists log4cxx as a dependency. The
warnings go away if this listing is removed.
// StdLibLinkingBug.h
#include <deque>
#include <string>
#ifndef STDLIBLINKINGBUG_H
#define STDLIBLINKINGBUG_H
void functionThatLogs(std::deque<std::string>);
#endif // STDLIBLINKINGBUG_H
// StdLibLinkingBug.cpp
#include "StdLibLinkingBug.h"
#include <log4cxx/logger.h>
using namespace std;
using namespace log4cxx;
LoggerPtr logger(Logger::getLogger("StdLibLinkingBug"));
void functionThatLogs(std::deque<std::string> aStringDeque)
{
LOG4CXX_WARN(logger,"A silly message " << aStringDeque.at(0))
}
Any help anyone can provide would be greatly appreciated. This bug has
me stumped!
Thanks,
Elaine
Elaine T. Hale, Ph.D.
Buildings and Thermal Systems Center
National Renewable Energy Laboratory
[EMAIL PROTECTED]
303-384-7812
MS 4111
