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copied!<p>The following shows an example of a shared class library shared.[h,cpp] and a main.cpp module using the library. It's a very simple example and the makefile could be made much better. But it works and may help you:</p> <p>shared.h defines the class:</p> <pre><code>class myclass { int myx; public: myclass() { myx=0; } void setx(int newx); int getx(); }; </code></pre> <p>shared.cpp defines the getx/setx functions:</p> <pre><code>#include "shared.h" void myclass::setx(int newx) { myx = newx; } int myclass::getx() { return myx; } </code></pre> <p>main.cpp uses the class,</p> <pre><code>#include <iostream> #include "shared.h" using namespace std; int main(int argc, char *argv[]) { myclass m; cout << m.getx() << endl; m.setx(10); cout << m.getx() << endl; } </code></pre> <p>and the makefile that generates libshared.so and links main with the shared library:</p> <pre><code>main: libshared.so main.o $(CXX) -o main main.o -L. -lshared libshared.so: shared.cpp $(CXX) -fPIC -c shared.cpp -o shared.o $(CXX) -shared -Wl,-soname,libshared.so -o libshared.so shared.o clean: $rm *.o *.so </code></pre> <p>To actual run 'main' and link with libshared.so you will probably need to specify the load path (or put it in /usr/local/lib or similar).</p> <p>The following specifies the current directory as the search path for libraries and runs main (bash syntax):</p> <pre><code>export LD_LIBRARY_PATH=. ./main </code></pre> <p>To see that the program is linked with libshared.so you can try ldd:</p> <pre><code>LD_LIBRARY_PATH=. ldd main </code></pre> <p>Prints on my machine:</p> <pre><code> ~/prj/test/shared$ LD_LIBRARY_PATH=. ldd main linux-gate.so.1 => (0xb7f88000) libshared.so => ./libshared.so (0xb7f85000) libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7e74000) libm.so.6 => /lib/libm.so.6 (0xb7e4e000) libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0xb7e41000) libc.so.6 => /lib/libc.so.6 (0xb7cfa000) /lib/ld-linux.so.2 (0xb7f89000) </code></pre>

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