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copied!<p>As Martin York pointed out, that's the way it works in Linux. When linking against a library, you have to link to all dependencies, too. That's different in Windows, DLLs take care of their dependencies themselves. When dynamically loading a library that has another library as a dependency, you need to load that library first with the RTLD_GLOBAL flag. This is pretty awkard, imho, since you may not be able to know which dependencies another shared objects requires, or the dependencies can change with a newer version that's otherwise binary compatible. From what I know (and from reading the g++ and ld manpages), it is not possible to create a behaviour similar to Windows' DLLs. Here's a little testcase:</p> <p>two.cpp:</p> <pre><code>#include <iostream> extern "C" { void bar() { std::cout << "bar()\n"; } } </code></pre> <p>one.cpp:</p> <pre><code>#include <iostream> extern "C" { void bar(); void foo() { std::cout << "foo()\n"; bar (); } } </code></pre> <p>test.cpp:</p> <pre><code>#include <dlfcn.h> #include <iostream> int main (int argc, char *argv[]) { using namespace std; // void *libtwo = dlopen("./libtwo.so", RTLD_NOW | RTLD_GLOBAL); void *libone = dlopen("./libone.so", RTLD_NOW); if (!libone) { cout << "dlopen(libone.so) failed: " << dlerror() << "\n"; return 1; } typedef void (*foo_t)(); foo_t foo = reinterpret_cast<foo_t>(dlsym(libone, "foo")); if (!foo) { cout << "dlsym(libone.so, foo) failed\n"; return 2; } } </code></pre> <p>one.cpp is compiled into <code>libone.so</code> and two.cpp in <code>libtwo.so</code>, test.cpp is compiled into the <code>test</code> binary. This will fail and only succeed when the commented line is uncommented.</p>

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