Many thanks Aidan,
Your suggestion of using the emscripten llvm-nm helped a lot, and I could
solve the link problems with opencv.
Concerning boost, I still have issues with the link. May be I am doing it
the wrong way.
Here is what I tried concerning the symbol
_ZN5boost6system16generic_categoryEv :
i) Check which lib uses it and which defines it :
The command :
for f in boost-emscripten-1.59/lib/libboost_*.a; do echo $f; em-llvm-nm
$f | grep _ZN5boost6system16generic_categoryEv; done
==> shows me that it is defined inside libboost_system.a :
boost-emscripten-1.59/lib/libboost_system.a
0000000000000000 T __ZN5boost6system16generic_categoryEv
ii) Add again this library at the end of the link command
==> this does not solve the issue
iii) Add "-Wl,--undefined=__ZN5boost6system16generic_categoryEv" to the
beginning of the link COMMAND
==> this does not help either
I will try other possibilities.
Do you have any other hint as to what I might have forgotten ?
Regards,
Pascal Thomet
On Saturday, September 5, 2015 at 4:01:22 PM UTC+2, Aidan Hobson Sayers
wrote:
>
> You've run nm against the .a file, not the .so (which is what you link).
> What happens if you try the typical approach of adding that file again to
> the end of your link command line?
>
> Additionally, are you using the system nm rather than llvm-nm (from the
> emscripten llvm build)?
>
> On 5 September 2015 at 14:45, Pascal Thomet <pth...@ivsweb.com
> <javascript:>> wrote:
>
>>
>> Hello Alon,
>>
>> Thanks again for your last answer.
>>
>> I have recompiled all the third party libraries in my project (they were
>> compiled by an older version of emscripten)
>>
>> This solved partially the problem :
>> 1) The linker does not ouput anymore errors like
>> "unexpected number of arguments 2 in call to
>> '_ZNKSt3__18ios_base6getlocEv'"
>> ==> this is good. I understand that it is advisable to compile all
>> the libraries and code with the same compiler version.
>>
>> 2) However I still have some link issues, and my study of these errors
>> makes me think there is a problem during the link
>> in the latest versions of emscripten. See the results of my analysis
>> below.
>>
>> i) When I link, I get the following errors :
>>
>> warning: unresolved symbol:
>> _ZN2cv9patchNaNsERKNS_17_InputOutputArrayEd
>> warning: unresolved symbol: _ZN2cv3hal8CholeskyEPfjiS1_ji
>> warning: unresolved symbol: _ZN5boost9re_detail13get_mem_blockEv
>> warning: unresolved symbol:
>> _ZN5boost9re_detail14verify_optionsEjNS_15regex_constants12_match_flagsE
>> warning: unresolved symbol: _ZN2cv3hal2LUEPfjiS1_ji
>> warning: unresolved symbol: cvCbrt
>> warning: unresolved symbol: _ZN2cv3hal8CholeskyEPdjiS1_ji
>> warning: unresolved symbol:
>> _ZN5boost9re_detail19raise_runtime_errorERKSt13runtime_error
>> warning: unresolved symbol:
>> _ZNK5boost9re_detail31cpp_regex_traits_implementationIcE9transformEPKcS4_
>> warning: unresolved symbol: _ZN5boost9re_detail13put_mem_blockEPv
>> warning: unresolved symbol:
>> _ZN5boost9re_detail24get_default_error_stringENS_15regex_constants10error_typeE
>> warning: unresolved symbol:
>> _ZNK5boost9re_detail31cpp_regex_traits_implementationIcE17transform_primaryEPKcS4_
>> warning: unresolved symbol:
>> _ZN2cv9RodriguesERKNS_11_InputArrayERKNS_12_OutputArrayES5_
>> warning: unresolved symbol: _ZN5boost6system15system_categoryEv
>> warning: unresolved symbol:
>> _ZN5boost11basic_regexIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE9do_assignEPKcS7_j
>> warning: unresolved symbol: _ZN2cv3hal2LUEPdjiS1_ji
>> warning: unresolved symbol: _ZN5boost6system16generic_categoryEv
>>
>> ii) Analysis of boost related link errors:
>> For example _ZN5boost6system16generic_categoryEv (ie
>> boost::system::generic_category() )
>> is actualy *present* in the boost library that I am linking, as show by
>> the output of nm below.
>> ==> the linker does not find however !
>>
>> nm boost-emscripten-1.59/lib/libboost_system.a | grep
>> _ZN5boost6system16generic_categoryEv
>> 0000000000000000 T __ZN5boost6system16generic_categoryEv
>>
>> iii) Study of opencv related link errors:
>> When I run nm (OSX version) on the opencv libraries I just built, I get
>> no output (!).
>> However, I am sure they contain many symbols, since I get many more
>> link errors if I do not link with them
>>
>> nm opencv-emscripten-3.0/lib/libopencv_core.a
>> ==> empty result`
>>
>> Do you have any ideas ?
>>
>> Regards,
>>
>> Pascal Thomet
>>
>>
>>
>>
>>
>>
>>
>> On Sunday, August 30, 2015 at 5:59:48 PM UTC+2, Alon Zakai wrote:
>>>
>>> Compiling just that code fragment works properly. Do you have a complete
>>> testcase showing the issue?
>>>
>>> One guess is that you are linking with boost, perhaps some sort of
>>> interaction between it and libc++.
>>>
>>>
>>> --
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>
>
>
> --
> Aidan
>
> Currently co-authoring a book on Docker -
> http://docker-in-practice.github.io/
>
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