Re: [Swig-user] Issue with compiling SWIG C++ to Python wrapper

[David F. <dav...@in...>]

Hi Carlos,

The second g++ invocation tries to link steam_api and python libraries and
steamworks_wrap.o object into an executable (a.out by default), but there
is no 'main' function.

You should create a shared library instead, which you can later import from
Python, something like this:

g++ -L/Users/aarzee/Documents/steamworks-sdk/redistributable_bin/osx32 -shared -o -libpysteam_api.dylib -lsteam_api -lpython steamworks_wrap.o

However, some other flags may be need, and using a setup.py file would be more reliable.

Hope it helps,
David

Quoting Carlos Liam (2015-03-31 17:31:27)
> I'm not sure if this is the right place to ask, but I'm not sure where else to look. I went on Stack Overflow ( http://stackoverflow.com/questions/29358095/issue-with-undefined-symbol-main-when-compiling-swig-wrapper ) but haven't received an answer.
> 
> I'm on Mac OS X 10.10.2 (64-bit) and I have the swig and swig-python packages installed through MacPorts, as well as Xcode and the command line tools installed.
> 
> I'm trying to create a wrapper from the Steamworks C++ API to Python. I have the following interface file (steamworks.i):
> 
> %module steamworks
> %{
> #define SWIG_FILE_WITH_INIT
> #include "/Users/aarzee/Documents/steamworks-sdk/public/steam/steam_api.h"
> %}
> 
> I'm running these commands:
> 
> swig -c++ -python steamworks.i
> g++ -O2 -fPIC -c steamworks_wrap.cxx -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7
> g++ -L/Users/aarzee/Documents/steamworks-sdk/redistributable_bin/osx32 -lsteam_api -lpython steamworks_wrap.o
> 
> The first two commands seem to work fine, but when I do the second g++ invocation, I get this error:
> 
> Undefined symbols for architecture x86_64:
>   "_main", referenced from:
>      implicit entry/start for main executable
> ld: symbol(s) not found for architecture x86_64
> clang: error: linker command failed with exit code 1 (use -v to see invocation)
> 
> I did a little research on this and it seems that this can be caused by premature linking, but I am using the -c option in the first g++ invocation.
> 
> Any help would be appreciated.
> 
>  - CL
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-- 
David Froger
SED-PRO
"C++ may not be the worst programming language ever created, but without a
doubt it’s the worst ever to be taken seriously."
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