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    <p>The problem is that on most <code>UNIX</code> platforms (unlike on <code>Win32</code> and <code>AIX</code>) all symbol references by default bind to the <em>first</em> definition of the symbol visible to the runtime loader.</p> <p>If you define <code>'operator new'</code> in the main <code>a.out</code>, everything will bind to that definition (as Neil Butterworth's example shows), because <code>a.out</code> is the very first image runtime loader searches.</p> <p>If you define it in a library which is loaded after <code>libC.so</code> (or <code>libstdc++.so</code> in case you are using <code>GCC</code>), then your definition will never be used. Since you are <code>dlopen()</code>ing your library after the program has started, <code>libC</code> is already loaded by that point, and your library is the very last one the runtime loader will search; so you lose. </p> <p>On <code>ELF</code> platforms, you may be able to change the default behavior by using <code>-Bsymbolic</code>. From <code>man ld</code> on Linux:</p> <pre><code> -Bsymbolic When creating a shared library, bind references to global symbols to the definition within the shared library, if any. Normally, it is possible for a program linked against a shared library to override the definition within the shared library. This option is only meaningful on ELF platforms which support shared libraries. </code></pre> <p>Note that <code>-Bsymbolic</code> is a linker flag, not a compiler flag. If using <code>g++</code>, you must pass the flag to the linker like this:</p> <pre><code> g++ -fPIC -shared library.cpp -o library.so -Wl,-Bsymbolic </code></pre>
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    1. POWhy isn't my new operator called
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    1. POWhy isn't my new operator called
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    1. COBut is this also the case if I explicitly overload the new/delete-operator in my library? I edited my original question so the problem is a bit more clear to see.
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    2. COYes, this is still the case. As far as runtime loader is concerned, you just defined two instances of a global function called _Znwj: one in the main executable, one in library.so. The first one runtime loader sees is the one it will use. As far is why -Bsymbolic didn't work; most likely you made a mistake: did you do 'g++ -g -Bsymbolic -Wall -fPIC -shared library.cpp -o library.so'? The '-Bsymbolic' is a linker switch, to pass it to the linker use '-Wl,-Bsymbolic'; otherwise it may be interpreted by GCC (which has a totally different meaning for -B... flags).
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    3. COOk, so I called "g++ -g -Wall -fPIC -shared -Wl,-Bsymbolic library.cpp -o library.so" and the client as I Wrote it in my question. But then again only the client's new/delete were called. I loaded the library dynamically, the client isn't linked to it at all. Is the linker switch "-Bsymbolic" also meant for this situation?
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