Hi everyone! I am relatively new to writing R extensions and to C programming. I thus hope that my question is not too basic. I am trying to load a shared object into R via the command dyn.load("convertR.so") and I get the following error: Error in dyn.load("convertR.so") : unable to load shared library '/Users/hadassa2/Documents/HUJI/Thesis/Sagiv_Project/LDhat/convertR.so': dlopen(/Users/hadassa2/Documents/HUJI/Thesis/Sagiv_Project/LDhat/convertR.so, 6): Symbol not found: _cmatrix Referenced from: /Users/hadassa2/Documents/HUJI/Thesis/Sagiv_Project/LDhat/convertR.so Expected in: dynamic lookup where cmatrix is a function defined in tools.c . I am including tools.h in convertR.c . Does this error mean that I need to create a shared object tools.so as well? Or in general: including other functions into a .so means they need to be of the type .so as well? Thanks a lot for any comments. Hadassa -- Hadassa Brunschwig PhD Student Department of Statistics The Hebrew University of Jerusalem http://www.stat.huji.ac.il