c++ dlopen plugin --> returns undefined symbol

[Thomas Drillich]

Hi

 I'm trying to run the C++ dlopen example from 
http://www.linux.org/docs/ldp/howto/C++-dlopen/thesolution.html. 
but I always get the error message 
"Cannot load library: .libs/libtriangle.so: undefined symbol: _ZTI7Polygon" 
 
 I see that the compiler renames the >Polygon< class, the >Polygon< class is
defined in a header file and included in main-program and plugin-lib. But
it seems that the compiler creates different symbol names each time. 
 
The compile lines attached below. 
 
thx in advance Thomas 

 -- build of main program -- 
 cd '<cpp-dlopentest>/debug/./src' && WANT_AUTOCONF_2_5="1"
WANT_AUTOMAKE_1_6="1" make -j2 cpp_dlopentest 
 if g++ -DHAVE_CONFIG_H -I. -I<cpp-dlopentest>/src -I.. -O0 -g3 -MT
cpp_dlopentest.o -MD -MP -MF ".deps/cpp_dlopentest.Tpo" -c -o
cpp_dlopentest.o <cpp-dlopentest>/src/cpp_dlopentest.cpp; then
mv -f ".deps/cpp_dlopentest.Tpo" ".deps/cpp_dlopentest.Po"; else
rm -f ".deps/cpp_dlopentest.Tpo"; exit 1; fi 
 /bin/sh ../libtool --tag=CXX --mode=link g++ -O0 -g3 -o cpp_dlopentest -ldl
cpp_dlopentest.o 
 mkdir .libs 
 g++ -O0 -g3 -o cpp_dlopentest cpp_dlopentest.o -ldl 
 -- END -- 
 -- build of libtriangle.so -- 
 cd '<cpp-dlopentest>/debug/./src' && WANT_AUTOCONF_2_5="1"
WANT_AUTOMAKE_1_6="1" make -j2 libtriangle.la 
 if /bin/sh ../libtool --tag=CXX --mode=compile
g++ -DHAVE_CONFIG_H -I. -I<cpp-dlopentest>/src -I.. -fPIC -O0 -g3 -MT
libtriangle_la-triangle.lo -MD -MP -MF ".deps/libtriangle_la-triangle.Tpo" -c -o
libtriangle_la-triangle.lo `test -f 'triangle.cpp' ||
echo '<cpp-dlopentest>/src/'`triangle.cpp; then
mv -f ".deps/libtriangle_la-triangle.Tpo" ".deps/libtriangle_la-triangle.Plo";
else rm -f ".deps/libtriangle_la-triangle.Tpo"; exit 1; fi 
 mkdir .libs 
 g++ -DHAVE_CONFIG_H -I. -I<cpp-dlopentest>/src -I.. -fPIC -O0 -g3 -MT
libtriangle_la-triangle.lo -MD -MP -MF .deps/libtriangle_la-triangle.Tpo -c
<cpp-dlopentest>/src/triangle.cpp -fPIC -DPIC -o 
.libs/libtriangle_la-triangle.o 
 <cpp-dlopentest>/src/triangle.cpp:36:2: warning: no newline at end of file 
 g++ -DHAVE_CONFIG_H -I. -I<cpp-dlopentest>/src -I.. -fPIC -O0 -g3 -MT
libtriangle_la-triangle.lo -MD -MP -MF .deps/libtriangle_la-triangle.Tpo -c
<cpp-dlopentest>/src/triangle.cpp -o libtriangle_la-triangle.o >/dev/null
2>&1 
 /bin/sh ../libtool --tag=CXX --mode=link g++ -O0 -g3 -o
libtriangle.la -rpath /usr/local/lib -module -shared
libtriangle_la-triangle.lo 

g++ -shared -nostdlib 
/usr/lib/gcc/x86_64-linux-gnu/4.1.2/../../../../lib64/crti.o 
/usr/lib/gcc/x86_64-linux-gnu/4.1.2/crtbeginS.o .libs/libtriangle_la-triangle.o 
-L/usr/lib/gcc/x86_64-linux-gnu/4.1.2 
-L/usr/lib/gcc/x86_64-linux-gnu/4.1.2/../../../../lib64 -L/lib/../lib64 
-L/usr/lib/../lib64 -lstdc++ -lm -lc -lgcc_s 
/usr/lib/gcc/x86_64-linux-gnu/4.1.2/crtendS.o 
/usr/lib/gcc/x86_64-linux-gnu/4.1.2/../../../../lib64/crtn.o -Wl,-soname 
-Wl,libtriangle.so.0 -o .libs/libtriangle.so.0.0.0 
 (cd .libs && rm -f libtriangle.so.0 && ln -s libtriangle.so.0.0.0
libtriangle.so.0) 
 (cd .libs && rm -f libtriangle.so && ln -s libtriangle.so.0.0.0
libtriangle.so) 
 -- END ---