I inadvertently upgraded my cygwin installation this morning to what __VERSION__ reports as "3.4.4 (cygming special) (gdc 0.12, using dmd 0.125)". The good news is that two freshly added dll tests which had been failing under gcc/cygwin 3.3.3 pass under 3.4.4. The bad news is that even though operations_test_dll is passing, statically linked operations_test fails. The reason for the static link failures is that the Windows function ::GetLastError() is returning 0 after several critical functions return error indications. I'm guessing from the "cygming" name that mingw is being used, and is the cause of the problem. Why the same problem doesn't appear when dynamically linking is unclear to me. My initial reaction is just to note the problem in the docs and move on. It seems to close to release to try workarounds, which would have to be very carefully done. Any other ideas? --Beman