[omniORB] Linking problems in MSVC++ 5.0

[Sai-Lai Lo]

I want to understand why you are getting these unresolved external symbol.

1. Did you manage to build the echo example (src/examples/echo) using
   nmake?

      Try in the directory
         nmake /f dir.mk

   If all goes well, you will get all the binaries compiled.
   If you do a DUMPBIN.EXE /SYMBOLS eg1.o, you will see that the external 
   symbol name of CORBA::string_free is ?string_free@CORBA@YAXPAD@Z.

2. If you succeed with step 1, have a look at the dir.mak file and compare 
   the compiler flags and libraries used in the file.
   The most relevant part is:

CORBA_CPPFLAGS = -D__WIN32__ -D__x86__ -D__NT__ -D__OSVERSION__=4
CORBA_LIB      = omniORB260_rt.lib omnithread2_rt.lib wsock32.lib \
                 advapi32.lib \
                 -libpath:$(TOP)\lib\x86_win32
CXXFLAGS       = -O2 -MD -GX $(CORBA_CPPFLAGS) $(DIR_CPPFLAGS)

    Notice the -MD and -GX flag.

3. In the same dir.mak file, there is an equilvalent set of the above to
   build debug executables. Have a look and use that as a guide.

4. I do not know the use of string.h is a problem. James, could you tell me
   more about this?


If you still have problems, do drop me a line. I think the instructions in
README.win32 file may be unclear. Please drop me a few lines as to how the
instructions can be improved.


Regards,

Sai-Lai


>>>>> Dee Jay Randall writes:

>   With Dominic's comments, I got my libc* problem solved. He was
> right on.

>   Would you recommend I compile multithreaded with static omni libs?
> I think I will need to do that anyway, in case we want to run the
> executable elsewhere, it would simplify installation requirements.

>   omni uses <string.h>, so I need to use the 'old' versions. Does this
> mean I won't be able to use the STL stuff? That would be bad, since
> the whole application that I'm trying to corba-ize is built on stuff
> in the STL. The link errors do not seem to be related to stl stuff.

>   My first three errors are now:
>> 
>> Linking...
>> server.obj : error LNK2001: unresolved external symbol "public: static void __cdecl CORBA::string_free(char *)" (?string_free@CORBA@@SAXPAD@Z)
>> dmvi.obj : error LNK2001: unresolved external symbol "public: static void __cdecl CORBA::string_free(char *)" (?string_free@CORBA@@SAXPAD@Z)
>> dmvi.obj : error LNK2001: unresolved external symbol "void __cdecl _CORBA_null_string_ptr(unsigned char)" (?_CORBA_null_string_ptr@@YAXE@Z)
>> 

>   grepping the runtime debug omni libraries for the functions
> gives me this:
>> C:\omniORB_2.6.1\lib\x86_win32>find "string_free" *rtd.lib
>> ---------- OMNILC22_RTD.LIB
>> ---------- OMNIORB260_RTD.LIB
>> ?string_free@CORBA@@YAXPAD@Z
>> __imp_?string_free@CORBA@@YAXPAD@Z
>> ?string_free@CORBA@@YAXPAD@Z
>> __imp_?string_free@CORBA@@YAXPAD@Z
>> ?string_free@CORBA@@YAXPAD@Z
>> __imp_?string_free@CORBA@@YAXPAD@Z
>> ---------- OMNITHREAD2_RTD.LIB
>> C:\omniORB_2.6.1\lib\x86_win32>find "null_string_ptr" *rtd.lib
>> ---------- OMNILC22_RTD.LIB
>> ---------- OMNIORB260_RTD.LIB
>> ?_CORBA_null_string_ptr@@YAX_N@Z
>> __imp_?_CORBA_null_string_ptr@@YAX_N@Z
>> ?_CORBA_null_string_ptr@@YAX_N@Z
>> __imp_?_CORBA_null_string_ptr@@YAX_N@Z
>> _??_CORBA_null_string_ptr@@YAX_N@Z
>> __imp_?_CORBA_null_string_ptr@@YAX_N@Z
>> ---------- OMNITHREAD2_RTD.LIB
>> C:\omniORB_2.6.1\lib\x86_win32>
>> 

>   So the functions are in there, but their symbols are not
> matched... ie: for string_free (omnilib) the mangled symbol is
> this "?string_free@CORBA@@YAXPAD@Z", but VC is looking for
> "?string_free@CORBA@@SAXPAD@Z". Likewise with CORBA_null_string_ptr.
> What on earth does this mean? And how do I fix it...

-- 
Dr. Sai-Lai Lo                          |       Research Scientist
                                        |
E-mail:         S.Lo@orl.co.uk          |       Olivetti & Oracle Research Lab
                                        |       24a Trumpington Street
Tel:            +44 223 343000          |       Cambridge CB2 1QA
Fax:            +44 223 313542          |       ENGLAND