Hi Chris, sorry for the late reply.
2. This compiles
gil::gil_function_requires<gil::ImageViewConcept<int> >();
What do you mean? This shouldn't compile?
I was under the impression that the point of gil_function_requires is to do static checking to ensure that a type is compatible with an GIL type? (Something akin to BOOST_CONCEPT_ASSERT)
To have the static checking kick in you need to enable it by #define BOOST_GIL_USE_CONCEPT_CHECK 1 before you include gil's headers. Hope that answers your question. Regards, Christian PS: In case you have some free time at hand, please consider writing a review for my gil's io extension which is currently reviewed by the boost community. Here is the a link to the announcement: http://lists.boost.org/boost-announce/2010/11/0273.php