Dear Enea, Dear all, I tried recently to implement a multi-thread version of my thesis code using PPL library. I used OpenMP and the last version of ppl on devel git branch as I read you have been working on a thread-safe implementation (thread-safe option with configure). I didn't succeed in writing a correct program; see for instance this simple code that return a segmentation fault : #include <omp.h> namespace PPL = Parma_Polyhedra_Library; int main(){ #pragma omp parallel for for(int i=0; i<1000; i++){ PPL::C_Polyhedron ph1(3); // => segmentation fault at line 83 of Linear_Expression.cc PPL::C_Polyhedron ph2(3); ph1.intersection_assign(ph2); } return 0; } Would you have any idea about what is wrong? Is PPL compatible with using OpenMP? Thanks a lot in advance, Thomas