On Tue, 21 Jun 2016, Patrick Welche wrote:
I'm trying to create a C++ loadable module. I thought it would be as easy as:
[ stuff removed ]
This fails with: /bin/sh ./libtool --tag=CXX --mode=link g++ -g -O2 -module -avoid-version -o hellow.la -rpath /usr/local/lib hellow.lo *** Warning: linker path does not have real file for library -lgcc. *** I have the capability to make that library automatically link in when *** you link to this library. But I can only do this if you have a *** shared version of the library, which you do not appear to have *** because I did check the linker path looking for a file starting *** with libgcc and none of the candidates passed a file format test *** using a regex pattern. Last file checked: /usr/lib/libgcc.a Presumably, this means that things aren't as simple as I thought. What am I missing?
Nothing is easy when it comes to C++-based modules. Risks are elevated if a C-based program uses C++-based modules due to unhandled C++ exceptions or C++ exceptions possibly not working.
You are going to need a shared library for the (correct) C++ run-time as well as libgcc_s.so. These need to somehow appear where libtool is searching for them. They will also need to be available in a path where the system searches for shared libraries in order to load the module.
# Dependencies to place before and after the objects being linked to # create a shared library. predep_objects="/usr/lib/crti.o /usr/lib/crtbeginS.o" postdep_objects="/usr/lib/crtendS.o /usr/lib/crtn.o" predeps="" postdeps="-lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc"
I am not sure what libgcc is used for. It seems to only ever be delivered as a static library in the GCC installation tree. Its appearance in the link line may be a bug (possibly a bug in GCC).
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ https://lists.gnu.org/mailman/listinfo/libtool
