[csw-maintainers] need help with C++ linker error from Sun's linker

[John Ellson]

Never mind.  I've found the problem.   It wasn't the "const char*const ...",
it was all the other args.


John



John Ellson wrote:
> James,
>
> Thanks.  I think I understand the issue, but I'm still not sure how to 
> fix it?
>
> I'm not that familiar with C++, but I don't see any mismatched 
> definitions in the code.
>
> Are you recommending that all "const char* const ... " in the sources 
> be changed to
> "const char* ... "  ?
> I'm a bit reluctant to make such an extensive change to the API of 
> this library.
> Is there a linker flag that would tell it to tolerate these extra 
> const's ?
>
> John
>
>
>
> James Lee wrote:
>> On 27/05/09, 19:25:50, John Ellson <ellson at opencsw.org> wrote regarding
>> [csw-maintainers] need help with C++ linker error from Sun's linker:
>>
>>  
>>> If I compile liblasi (mgar/pkg/liblasi/trunk) using g++ it compiles and
>>> links without problem.
>>>     
>>
>>  
>>> If I use Sun's tools  (remove the line: "CXX=/opt/csw/gcc4/bin/g++ \"
>>> from the Makefile)
>>> then I get this error:
>>>     
>>
>> ...
>>
>>  
>>> Undefined                       first referenced
>>>  symbol                             in file
>>> void LASi::PostscriptDocument::setFont(const
>>>
>>>     
>> char*const,LASi::FontStyle,LASi::FontWeight,LASi::FontVariant,LASi::Font
>> St
>> retch)
>>  
>>> CMakeFiles/example0.dir/MissingGlyphExample.o
>>> ld: fatal: Symbol referencing errors. No output written to example0
>>>     
>>
>>
>>
>>  
>>> There's something odd about the "const char*const"   but I don't 
>>> know if
>>> thats related.
>>>     
>>
>>
>> I think you've almost answered your own question.   gcc does not use
>> "const" type qualifier for types passed by value when making external
>> names.  So "const char*const" is the same as "const char*" on the call
>> because the value is copied anyway (the second "const" is of benefit to
>> the compiler in the function only).  Nevertheless CC likes consistency
>> so try matching the "const"s in all function declarations.
>>
>>
>>
>>
>> $ cat sub.cc
>> void sub(const char*const arg)
>> {
>>     return;
>> }
>>
>> $ g++ -c sub.cc
>> $ nm -C sub.o
>>
>>
>> sub.o:
>>
>> [Index]   Value      Size    Type  Bind  Other Shndx   Name
>>
>> [2]     |         0|       0|SECT |LOCL |0    |1      |
>> [3]     |         0|       0|SECT |LOCL |0    |2      |
>> [4]     |         0|       0|SECT |LOCL |0    |3      |
>> [5]     |         0|       0|SECT |LOCL |0    |4      |
>> [6]     |         0|      16|FUNC |GLOB |0    |1      |sub(const char*)
>>                                                        [_Z3subPKc]
>> [1]     |         0|       0|FILE |LOCL |0    |ABS    |sub.cc
>>
>> $ CC -c sub.cc
>> $ nm -C sub.o
>>
>>
>> sub.o:
>>
>> [Index]   Value      Size    Type  Bind  Other Shndx   Name
>>
>> [1]     |         0|       0|FILE |LOCL |0    |ABS    |sub.cc
>> [2]     |        16|      24|FUNC |GLOB |0    |2      |void sub(const
>> char*const)
>>
>> [__1cDsub6Fkpkc_v_]
>>
>>
>>
>>
>> James.
>> _______________________________________________
>> maintainers mailing list
>> maintainers at lists.opencsw.org
>> https://lists.opencsw.org/mailman/listinfo/maintainers
>>
>>   
>
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