I took further tests : - it works perfectly under Ubuntu 8.04 and GCC 4.1 - fails (with a big crash) with GCC 4.1 (MinGW) I really have no clue why this does not work. I tried to play with the stack reserve (in VS.net) but it didn't work. I thought maybe it's because I mix C/C++ in the binary (yes, I'm really desperate to have this work). So a little summary of the problem : I want to embed Ruby but instead of using the library (.lib or .a and/ or .so or .dll) I link the .c of Ruby directly. This does work (it created a proper binary) but has problems with the load path and/or require. Any message will be taken into account. Thanks. Remi Gillig.