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PODynamic symbol lookup fails with statically embedded Python on Mac OS X
 

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    <p>I'm building a Mac OS X application that is to embed Python. My application is technically a bundle (i.e. its main executable is MH_BUNDLE); it's a plug-in for another application. I'd like it to embed Python statically, but want to be able to load extensions dynamically.</p> <p>I did the following: I included a whole library (<code>-force_load path/to/libpython2.7.a</code>), also reexported all Python symbols (<code>-exported_symbol_list path/to/list</code>), and added the <code>-u _PyMac_Error</code>, which I got using <a href="http://docs.python.org/extending/embedding.html#linking-requirements" rel="nofollow">this linking advice</a>. The bundle itself loads fine, all internal Python code appears to work, but it fails when it it tries to import a dynamic library (<code>time.so</code>) with the following message:</p> <pre><code>Traceback (most recent call last): ... ImportError: dlopen(/&lt;stripped&gt;/time.so, 2): Symbol not found: _PyExc_OverflowError Referenced from: /&lt;stripped&gt;/time.so Expected in: dynamic lookup </code></pre> <p>This symbol is a part of Python API and it must be in my bundle already. I can check this:</p> <pre><code>nm -g Build/Debug/pyfm | grep _PyExc_OverflowError 00172884 D _PyExc_OverflowError 0019cde0 D _PyExc_OverflowError </code></pre> <p>(It's listed twice because I have two architectures, i386 and ppc). </p> <p>The <code>time.so</code> doesn't reference anything, which, as I understand, is by design:</p> <pre><code>otool -L "/&lt;stripped&gt;/time.so" /&lt;stripped&gt;/time.so (architecture ppc): /usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 88.3.11) /&lt;stripped&gt;/time.so (architecture i386): /usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 88.3.11) </code></pre> <p>My problem appears to be similar to <a href="http://bugs.python.org/issue4434" rel="nofollow">this</a>, but it's the other way round: I do link Python statically, while the other poster linked it dynamically (an our platforms are different too). For him static linking solved the problem. </p> <p>Why doesn't it find the symbol?</p> <p><strong>Update.</strong> I suspect it happens because the main app loads its plug-ins (and thus my bundle) with <code>RTLD_LOCAL</code>.</p>
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