g++ linking issue when loading external shared library

Question

I am compiling my own .so library which uses other (external) .so library. I created my own CMakeLists.txt. For external library I use provided CMakeList.txt and add it to project in my CMakeLists.txt (add_subdirectory). I got stuck with linking. My library can't load external module.

It says

undefined symbol: _Z13SomeFunctionhhhiiiPchhddhhhS_h

When I check external .so module for symbol I found

_Z13SomeFunctionbbbiiiPcbbddbbbS_b

Thus, symbol is presented in .so module, but names do not match.

Any help?

`extern "C"` should help. See [Name mangling](http://en.wikipedia.org/wiki/Name_mangling) — Ivan Aksamentov - Drop, Nov 24 '14 at 11:46

Rodolphe Chartier · Answer 1 · 2014-11-24T11:54:08.263

-1

I think the compiler cannot find .so moduls. You probably have to compile with these flags -L and -l. If your lib is called libmy.so you will have to use: g++ *.c -L path/to/libmy/ -lmy

EDIT

The external lib.so path must be in the LD_PRELOAD environment variable, check this then.

edited Nov 24 '14 at 11:54

answered Nov 24 '14 at 11:42

Rodolphe Chartier

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I see the correct path to the library in ldd mylib.so. – Fedor Nikitin Nov 24 '14 at 11:46
the issue occur when you're trying to compile your own .so ? – Rodolphe Chartier Nov 24 '14 at 11:48
check if your calls in your .so module to the other external .so module is correct, check the name of each function and check if you didn't miss type the .so name module in the linker – Rodolphe Chartier Nov 24 '14 at 11:50

g++ linking issue when loading external shared library

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