Problem with multiply defined symbols in a mixed-mode DLL

  • Thread starter Thread starter John
  • Start date Start date
J

John

I have 5 native static libraries that are being compiled in Visual
Studio 2005 with the /MDd C Runtime option. I have 2 CLR DLLs (all
managed code) in Visual Studio 2005 and the /MDd C Runtime setting.
They are in the same solution, and compile/link without problems (Debug
configuration).

I also have 1 mixed-mode CLR DLL that consumes both the static
libraries and managed DLLs. It is configured to use the /MDd C Runtime
library. When I add it to the solution (making sure its references are
correct), it gives linking errors shown below.

I am a relatively young developer, spoiled by Java and C#. I
understand that the problems indicate an attempt to link against 2
versions of the C Runtime Library -- but I have no idea what settings
to check (or what to look for in the code) in order to resolve the
problem. I have been making sure that C++ --> Code Generation -->
Runtime Library is set to /MDd for everything. Are there other
settings or places in code that could cause me to link to another
version?

Thanks for any advice you could give,
John

-----=[ Begin Example Linking Errors ]=-----
LINK : warning LNK4098: defaultlib 'LIBCMTD' conflicts with use of
other libs; use /NODEFAULTLIB:library

libcpmtd.lib(cerr.obj) : error LNK2005: "public: __thiscall
std::basic_ostream said:
::basic_ostream<char,struct std::char_traits<char> >(class std::basic_streambuf<char,struct std::char_traits<char> > *,bool)" (??0?$basic_ostream@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@_N@Z) already defined in msvcprtd.lib(MSVCP80D.dll)
Click to expand...

LIBCMTD.lib(stdexcpt.obj) : error LNK2005: "public: __thiscall
std::exception::exception(void)" (??0exception@std@@QAE@XZ) already
defined in MSVCRTD.lib(MSVCR80D.dll)

C:\path\MixedMode.dll : fatal error LNK1169: one or more multiply
defined symbols found
 
John said:
I have 5 native static libraries that are being compiled in Visual
Studio 2005 with the /MDd C Runtime option. I have 2 CLR DLLs (all
managed code) in Visual Studio 2005 and the /MDd C Runtime setting.
They are in the same solution, and compile/link without problems
(Debug
configuration).

I also have 1 mixed-mode CLR DLL that consumes both the static
libraries and managed DLLs. It is configured to use the /MDd C
Runtime
library. When I add it to the solution (making sure its references
are
correct), it gives linking errors shown below.

I am a relatively young developer, spoiled by Java and C#. I
understand that the problems indicate an attempt to link against 2
versions of the C Runtime Library -- but I have no idea what settings
to check (or what to look for in the code) in order to resolve the
problem. I have been making sure that C++ --> Code Generation -->
Runtime Library is set to /MDd for everything. Are there other
settings or places in code that could cause me to link to another
version?
Click to expand...

Something in that mix was compiled with /MTd, not /MDd. Re-check your
project settings for everything in the link, and make sure to do a
Rebuild-All.

You can also use

dumpbin /directives myfile.obj (or .lib)

to see the defaultlib directives in an object or library file. That could
help you pin down which module is at fault.

-cd
 
Carl,

Thanks very much for telling me about the 'dumpbin' command: I never
knew about it. I've run it on one of the native libraries, and have
come up with the output below.

I can see that this library has "/DEFAULTLIB:LIBCMTD" but I'm confused
as to why because my C++ --> Code Generation --> Runtime Library is set
to "/MDd" and my librarian command line looks like the following:
/OUT:"Debug\native.lib" /NOLOGO /NODEFAULTLIB:"libcmtd.lib"
/NODEFAULTLIB:"libcpmtd.lib"

When I set my libraries and DLLs to compile with option /MDd, which C
Runtime Library should I expect to see in /dumpbin? libcmdd.lib?

As you can see, I've done enough searching/reading to know what my
problem is. But every time someone has this sort of problem, the
answer is always, "oh, just make sure you're linking against the same C
Runtime throughout" -- with no explaination of which settings to check
in the project's properties, so I'm very lost. =(

Can anyone please help me understand what my next steps should be?

Thanks!
John


-----=[ Begin /dumpbin output ]=-----
Microsoft (R) COFF/PE Dumper Version 7.10.3077
Copyright (C) Microsoft Corporation. All rights reserved.


Dump of file native.lib

File Type: LIBRARY

Linker Directives
-----------------
/manifestdependency:"type='win32'
name='Microsoft.VC80.DebugCRT'
version='8.0.50608.0'
processorArchitecture='x86'
publicKeyToken='1fc8b3b9a1e18e3b'"
/DEFAULTLIB:"msvcprtd"
/manifestdependency:"type='win32'
name='Microsoft.VC80.DebugCRT'
version='8.0.50608.0'
processorArchitecture='x86'
publicKeyToken='1fc8b3b9a1e18e3b'"

/alternatename:__imp_??$?5DU?$char_traits@D@std@@@std@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@0@AAV10@AAD@Z=__imp_??5std@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@0@AAV10@AAD@Z
/DEFAULTLIB:"MSVCRTD"
/DEFAULTLIB:"OLDNAMES"

Linker Directives
-----------------
/DEFAULTLIB:"libcpmtd"
/DEFAULTLIB:"LIBCMTD"
/DEFAULTLIB:"OLDNAMES"

Linker Directives
-----------------
/DEFAULTLIB:"libcpmtd"
/DEFAULTLIB:"LIBCMTD"
/DEFAULTLIB:"OLDNAMES"

Linker Directives
-----------------
/DEFAULTLIB:"LIBCMTD"
/DEFAULTLIB:"OLDNAMES"

Linker Directives
-----------------
/DEFAULTLIB:"libcpmtd"
/DEFAULTLIB:"uuid.lib"
/DEFAULTLIB:"uuid.lib"
/include:?id@?$numpunct@D@std@@2V0locale@2@A

/include:?id@?$num_put@DV?$ostreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@2V0locale@2@A
/DEFAULTLIB:"LIBCMTD"
/DEFAULTLIB:"OLDNAMES"

Summary

E8 .CRT$XCU
6A1 .bss
685 .data
4CEB8 .debug$S
208 .debug$T
3EE .drectve
114D .rdata
9DD .rdata$r
14 .rtc$IMZ
14 .rtc$TMZ
19C .sxdata
1360A .text
135A .text$x
67B .text$yc
1A2 .text$yd
19E0 .xdata$x
 
John said:
Carl,

Thanks very much for telling me about the 'dumpbin' command: I never
knew about it. I've run it on one of the native libraries, and have
come up with the output below.

I can see that this library has "/DEFAULTLIB:LIBCMTD" but I'm confused
as to why because my C++ --> Code Generation --> Runtime Library is
set
to "/MDd" and my librarian command line looks like the following:
Click to expand...

OK, your project is set correctly. The next step is to check the settings
on every individual .cpp file in the project. Those settings can be
overridden on a file by file basis.
/OUT:"Debug\native.lib" /NOLOGO /NODEFAULTLIB:"libcmtd.lib"
/NODEFAULTLIB:"libcpmtd.lib"
Click to expand...

I'm not sure that the /nodefaultlib option has any bearing on the lib
command (which is really just a wrapper over link /lib).
When I set my libraries and DLLs to compile with option /MDd, which C
Runtime Library should I expect to see in /dumpbin? libcmdd.lib?
Click to expand...

You should see msvcrtd.lib
As you can see, I've done enough searching/reading to know what my
problem is. But every time someone has this sort of problem, the
answer is always, "oh, just make sure you're linking against the same
C
Runtime throughout" -- with no explaination of which settings to check
in the project's properties, so I'm very lost. =(

Can anyone please help me understand what my next steps should be?
Click to expand...

-cd
 
Carl said:
OK, your project is set correctly. The next step is to check the settings
on every individual .cpp file in the project. Those settings can be
overridden on a file by file basis.
Click to expand...

Carl,

That was the problem. I didn't know that individual files could
overwrite the project-level setting! Some of them were - as you can
guess - set to /MTd.

After resetting every single file (groan) for /MDd, everything compiles
and links!

Thanks so much!
John
 
John said:
Carl,

That was the problem. I didn't know that individual files could
overwrite the project-level setting! Some of them were - as you can
guess - set to /MTd.

After resetting every single file (groan) for /MDd, everything compiles
and links!
Click to expand...

Glad it worked!

Those per-file overrides are really handy when you need 'em, but quite a
nuisance when you don't know they're there! There were problems with
project conversion from VC6 to VC7 (and 7.1, I think) that would sometimes
duplicate project-level settings as file-level settings, so if your project
was migrated from VC6 through VC7.x, that may be how those per-file settings
got in there.

-cd
 
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