Morning,
I'm attempting to make a c++ api wrapper to an existing library. I'm
having some trouble getting past the basics. My first stop was the
manual, but I could not get the Rectangle Demo to compile on my
system. Some searching of the mailing list found a thread where
someone was kind enough to post corrections to the wiki and manual
entries (http://codespeak.net/pipermail/cython-dev/2008-April/000516.html
).
With this I was able to get the example to compile, but quickly ran
into issues of my own when trying to duplicate it for my library.
The library is installed into /opt/local with headers in /opt/local/
include/mp4v2 and libs in /opt/local/lib. I was going to first attempt
to duplicate the examples provided by the project. The first step
would be to declare a MP4FileHandle object and open it with
MP4Modify(). It would look something like this:
> #include <stdio.h>
> #include <string.h>
> #include <stdlib.h>
> #include <mp4v2/mp4v2.h>
>
> int main (int argc, char const **argv)
> {
> MP4FileHandle file = MP4Modify(argv[1], MP4_DETAILS_ERROR, 0);
> if(file == MP4_INVALID_FILE_HANDLE) {
> printf("MP4Modify failed\n");
> return 1;
> }
>
> MP4Close(file);
>
> return 0;
> }
Obviously, the MP4* definitions are found in mp4v2/mp4v2.h. Compiling
is also straight forward:
> g++ -I/opt/local/include -L/opt/local/lib -lmp4v2 main.cpp
Now, on to duplicating or declaring these in a cython interface file.
I put together a setup.py like so:
> from distutils.core import setup
> from distutils.extension import Extension
> from Cython.Distutils import build_ext
>
> utils = Extension(
> "utils",
> sources=["pymp4v2/utils.pyx"],
> include_dirs=["/opt/lcoal/include/"],
> libraries=["mp4v2"],
> library_dirs=['/opt/local/lib'],
> language="c++",
> define_macros=[('MACOSX_DEPLOYMENT_TARGET', 10.5)],
> )
>
> setup(
> ext_modules = [utils],
> cmdclass={'build_ext':build_ext},
>
>
> )
I then created the following pyx file and attempted build. I tried
various other combos e.g. cdef extern from "mp4v2.mp4v2.h" or "mp4v2/
mp4v2.h".
any guidance is greatly appreciated. I'm sure I'm missing some section
of the documentation that explains this, my apologies if that's the
case.
-james
> """
> Python Wrapper Interface for libmp4v2 methods.
> """
> cdef extern from "mp4v2.h":
> void* MP4FileHandle
> MP4FileHandle MP4Modify(char* fileName, int verbosity=0, int
> flags = 0)
> running build_ext
> cythoning pymp4v2/utils.pyx to pymp4v2/utils.cpp
>
> Error converting Pyrex file to C:
> ------------------------------------------------------------
> ...
> """
> Python Wrapper Interface for libmp4v2 methods.
> """
> cdef extern from "mp4v2.h":
> void* MP4FileHandle
> MP4FileHandle MP4Modify(char* fileName, int verbosity=0, int
> flags = 0) ^
> ------------------------------------------------------------
>
> /Users/jkyle/Projects/pymp4v2.env/src/python/pymp4v2/utils.pyx:6:4:
> 'MP4FileHandle' is not a type identifier
> building 'utils' extension
> /usr/bin/gcc-4.0 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -
> g -fwrapv -O3 -Wall -Wstrict-prototypes -
> DMACOSX_DEPLOYMENT_TARGET=10.5 -I/opt/lcoal/include/ -I/opt/local/
> Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -
> c pymp4v2/utils.cpp -o build/temp.macosx-10.3-i386-2.6/pymp4v2/utils.o
> cc1plus: warning: command line option "-Wstrict-prototypes" is valid
> for C/ObjC but not for C++
> pymp4v2/utils.cpp:1:2: error: #error Do not use this file, it is the
> result of a failed Cython compilation.
> error: command '/usr/bin/gcc-4.0' failed with exit status 1
>
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