How to resolve a “conflicting types” error during C++/C compilation using `python setup.py build`?

Question

I'm trying to include the COLLADA DOM library into a program I'm working on ( PyMOL ) as an external dependency, with the ultimate goal of enabling export of 3D scenes in COLLADA (.dae) format. I'm able to successfully compile everything up to the point where I add #include <Collada14Dom/dae.h> to the relevant source file; ie if I comment-out that single line, everything builds fine. I'm working on a Mac running 10.8.5 with Xcode 5.

So far, I've installed the COLLADA DOM v2.2 from Sourceforge, built the DOM via make (from within the 'dom' subdirectory), and installed the framework to /Library/Frameworks/Collada14Dom.framework via make install .

I've also downloaded Boost v1.55.0 and installed via ./bootstrap , ./b2 , ./b2 install as indicated here .

The problem arises when I compile after adding the following line to my COLLADA.cpp file.

#include <Collada14Dom/dae.h>

Upon compilation, I get a series of "conflicting types" errors:

$ sudo /sw/bin/python setup.py build install --home=/opt/pymol --install-lib=/opt/pymol/modules --install-scripts=/opt/pymol
Password:
running install
running build
running build_py
running build_ext
building 'pymol._cmd' extension
gcc -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -D_PYMOL_VMD_PLUGINS -D_PYMOL_LIBPNG -D_PYMOL_FREETYPE -D_PYMOL_INLINE -D_PYMOL_OPENGL_SHADERS -DNO_MMLIBS -D_PYMOL_CGO_DRAWARRAYS -D_PYMOL_CGO_DRAWBUFFERS -D_CGO_DRAWARRAYS -D_PYMOL_GL_CALLLISTS -DOPENGL_ES_2 -D_PYMOL_COLLADA -D_PYMOL_NUMPY -Iov/src -Ilayer0 -Ilayer1 -Ilayer2 -Ilayer3 -Ilayer4 -Ilayer5 -Imodules/cealign/src -Imodules/cealign/src/tnt -Ibuild/generated -Icontrib/uiuc/plugins/include -Icontrib/uiuc/plugins/molfile_plugin/src -I/sw/lib/python2.7/site-packages/numpy/core/include -I/usr/include -I/usr/X11/include -I/usr/X11/include/freetype2 -I/sw/include -I/sw/include/freetype2 -I/sw/include/python2.7 -c layer1/COLLADA.cpp -o build/temp.macosx-10.8-x86_64-2.7/layer1/COLLADA.o -ffast-math -funroll-loops -O3 -fcommon
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:67:
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:91:5: error: conflicting types for '__distance'
    __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:74:5: note: previous definition is here
    __distance(_InputIterator __first, _InputIterator __last,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:133:5: error: conflicting types for '__advance'
    __advance(_BidirectionalIterator& __i, _Distance __n,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:123:5: note: previous definition is here
    __advance(_InputIterator& __i, _Distance __n, input_iterator_tag)
    ^
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:149:5: error: conflicting types for '__advance'
    __advance(_RandomAccessIterator& __i, _Distance __n,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator_base_funcs.h:123:5: note: previous definition is here
    __advance(_InputIterator& __i, _Distance __n, input_iterator_tag)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
In file included from /usr/include/c++/4.2.1/bits/stl_iterator.h:69:
/usr/include/c++/4.2.1/bits/cpp_type_traits.h:92:10: error: functions that differ only in their return type cannot be
      overloaded
  __two& __test_type(...);
         ^
/usr/include/c++/4.2.1/bits/cpp_type_traits.h:90:9: note: previous declaration is here
  __one __test_type(int _Tp::*);
        ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:282:5: error: conflicting types for 'operator=='
    operator==(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:96:5: note: previous definition is here
    operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:288:5: error: conflicting types for 'operator<'
    operator<(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:102:5: note: previous definition is here
    operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:294:5: error: conflicting types for 'operator!='
    operator!=(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:109:5: note: previous definition is here
    operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:300:5: error: conflicting types for 'operator>'
    operator>(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:115:5: note: previous definition is here
    operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:306:5: error: conflicting types for 'operator<='
    operator<=(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:121:5: note: previous definition is here
    operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:312:5: error: conflicting types for 'operator>='
    operator>=(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:127:5: note: previous definition is here
    operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:332:5: error: conflicting types for 'operator=='
    operator==(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:96:5: note: previous definition is here
    operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:338:5: error: conflicting types for 'operator<'
    operator<(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:102:5: note: previous definition is here
    operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:344:5: error: conflicting types for 'operator!='
    operator!=(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:109:5: note: previous definition is here
    operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:350:5: error: conflicting types for 'operator>'
    operator>(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:115:5: note: previous definition is here
    operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:356:5: error: conflicting types for 'operator<='
    operator<=(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:121:5: note: previous definition is here
    operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:362:5: error: conflicting types for 'operator>='
    operator>=(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_pair.h:127:5: note: previous definition is here
    operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
    ^
In file included from layer1/COLLADA.cpp:35:
In file included from /Library/Frameworks/Collada14Dom.framework/Headers/dae.h:28:
In file included from /usr/local/include/boost/filesystem/convenience.hpp:22:
In file included from /usr/local/include/boost/filesystem/operations.hpp:25:
In file included from /usr/local/include/boost/filesystem/path.hpp:25:
In file included from /usr/local/include/boost/filesystem/path_traits.hpp:23:
In file included from /usr/local/include/boost/system/error_code.hpp:17:
In file included from /usr/local/include/boost/operators.hpp:86:
In file included from /usr/local/include/boost/iterator.hpp:17:
In file included from /usr/include/c++/4.2.1/iterator:68:
/usr/include/c++/4.2.1/bits/stl_iterator.h:368:5: error: conflicting types for 'operator-'
    operator-(const reverse_iterator<_IteratorL>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator.h:318:5: note: previous definition is here
    operator-(const reverse_iterator<_Iterator>& __x,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator.h:738:5: error: conflicting types for 'operator=='
    operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator.h:732:5: note: previous definition is here
    operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator.h:750:5: error: conflicting types for 'operator!='
    operator!=(const __normal_iterator<_Iterator, _Container>& __lhs,
    ^
/usr/include/c++/4.2.1/bits/stl_iterator.h:744:5: note: previous definition is here
    operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
    ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
error: command 'gcc' failed with exit status 1

Clearly GCC is having issues with the C++ headers, but I'm not sure how to resolve this.

One important consideration is that there is no other C++ code in the project codebase. (There is no C-based COLLADA library, and I really don't want to reinvent the wheel here.) So it seems likely that there is some configuration that needs to happen--some setting in setup.py, perhaps. Is there any way to tell setup.py to use something other than GCC to compile?

For what it's worth, I can fully reproduce the problem (after installing COLLADA DOM and Boost) with the following:

sscce.cpp:

#ifdef __cplusplus
extern "C" {
#endif

#include <Collada14Dom/dae.h>

int main(){
    return 0
}

#ifdef __cplusplus
}  // END extern "C"
#endif

which, if I try to build using gcc sscce.cpp , yields the same kinds of "conflicting types" errors as with the full program. Oddly (to me, anyway), I also get the same errors using g++ sscce.cpp so I guess it may not be strictly a GCC problem.

What am I missing? Hopefully someone has seen this kind of thing before, and you won't actually have to install COLLADA DOM and Boost to be able to offer suggestions, as both libraries take some time to build. As always, any help would be much appreciated.

Thanks!

Answer 1

Functions in this C++ file needs to be callable by other C code in the project, so I was under the impression I needed to enclose the C++ code in extern "C" blocks to avoid name mangling. Is that not the case?

extern "C" blocks allow C declarations to be embedded in C++ code, while you want the reverse; no provision exists for that.