Hi all, I've decided to "cross-post" the message below to boost devel mailing list in the hope someone can answer to my questions. Sorry for the duplicate Ciao! -- Marco ---------- Forwarded message ---------- From: Marco Guazzone <marco.guazzone@gmail.com> Date: Thu, Jun 4, 2009 at 3:40 PM Subject: [Math/Statistical Distributions] Help on using distributions' global accessors To: boost-users@lists.boost.org Dear Boost users, I don't understand why the code in the attached file "test_distributions_ko.zip" does not work. :( It compiles without problems, but as I run it I get the following error as soon as the *variance* accessor is called: --- [error] --- Running 2 test cases... ... unknown location(0): fatal error in "exponential_distribution": memory access violation at address: 0x7fffa6254ff8: no mapping at fault address test.cpp(34): last checkpoint *** 1 failure detected in test suite "test::stats test suite" --- [/error] --- I've also tried to replace the use of inheritance with the removal of class "exponential_distribution" and directly injecting inside my namespace the Boost one, that is: namespace test { namespace stats {  using ::boost::math::exponential_distribution;  using ::boost::math::exponential; }} but without success. Instead, the error *disappear* if I use the code in "test_distributions_ok.zip", where instead of using inheritance and "injection" I use membeship (i.e., composition). Why? My compiler is GCC 4.3.2 and my system is Fedora 10 x86_64. If you want to try the attached code you can simply type 'make' from your shell (provided you have a unix like system) and then run the command "./test". A note about the code: you may ask yourself why I'm redefining some functions already defined by the Boost library. The reason lies in the fact that my final goal is to create a wrapping library in order to change without pain the underlying real implementation. An help or a hint would be very very very appreciated!! :) Thank you very much! -- Marco