[C++-sig] [Py++] Generate Python code for ctypes?

[Roman Yakovenko]

On Sun, Dec 13, 2009 at 8:24 PM, Nikolaus Rath <Nikolaus at rath.org> wrote:
> Roman Yakovenko <roman.yakovenko at gmail.com> writes:
>> On Sun, Dec 13, 2009 at 4:54 AM, Nikolaus Rath <Nikolaus at rath.org> wrote:
>>> Roman Yakovenko <roman.yakovenko at gmail.com> writes:
>>>> You can take a look on gmplib example:
>>>> http://pygccxml.svn.sourceforge.net/viewvc/pygccxml/pyplusplus_dev/examples/gmplib_dev/
>>>> It is fully working.
>>>
>>> Do I need the CVS version?
>>
>> Yes. The version, which contains ctypes code generator, was not released yet.
>
> Alright, now it seems to work great already! But I have another question
> right away:
>
> The generated code contains
>
> libfuse_lib = ctypes.CDLL( r"/usr/lib/libfuse.so" )
>
> I'd rather have the library looked up dynamically, as in
>
> libfuse = CDLL(find_library("fuse"))
>
> but it seems that I have to hardcode the complete path in
> project_env.py, otherwise I get:
>
> Traceback (most recent call last):
>  File "generate_code.py", line 15, in <module>
>    mb = ctypes_module_builder_t( [project_env.gmp.header_file], project_env.gmp.symbols_file, gccxml_cfg )
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pyplusplus/module_builder/ctypes_builder.py", line 42, in __init__
>    self.__blob2decl = binary_parsers.merge_information( self.global_ns, exported_symbols_file )
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pygccxml/binary_parsers/parsers.py", line 303, in merge_information
>    symbols = parser.parse()
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pygccxml/binary_parsers/parsers.py", line 95, in parse
>    self.__loaded_symbols = self.load_symbols()
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pygccxml/binary_parsers/parsers.py", line 256, in load_symbols
>    mangled_smbls = self.__extract_symbols( [part % tmpl_args for part in self.cmd_mangled] )
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pygccxml/binary_parsers/parsers.py", line 246, in __extract_symbols
>    output = self.__execute_nm( cmd )
>  File "/home/nikratio/.local/lib/python2.6/site-packages/pygccxml/binary_parsers/parsers.py", line 242, in __execute_nm
>    raise RuntimeError( os.linesep.join(msg) )
> RuntimeError: Unable to extract public\exported symbols from 'libfuse.so.2' file.
> The command line, which was used to extract symbols, is "['nm', '--extern-only', '--dynamic', '--defined-only', '--numeric-sort', 'libfuse.so.2']"
>
> Is there a way to accomplish this?

The functionality you ask doesn't exist right now. If I remember
right, ctypes module has "look for a library" functionality. I will
take a look how to integrate it with Py++.

Your ideas ( and patches ) are welcome.

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/