Hello, I started a thread on Boost-users about the proposed endian library, but it's probably more suitable on the dev list. Here's a link to the thread in the archives: <http://lists.boost.org/boost-users/2006/07/20887.php> I see two issues with the library as of 0.5. First, the endian classes cannot be used in unions. And, second the classes cannot be used in variable argument lists. I'm attaching a patch to help resolve both of these issues. In order to be used in a union, a class must not have any constructors. However, removing constructors breaks the following code: big4_t x = 42; My solution was to provide a static init() method to help in these situations: big4_t x = big_t::init(42); The second problem shows up using varargs. For example, this will not compile: printf("x = %d\n", x); The solution I came up with is to use operator() to get the native value: printf("x = %d\n", x()); In my patch, I've also added a check_unions() function to endian_test.cpp that tests the sizes of unions. Thanks, -Dave