I'm new to Cygwin. I installed it today (latest release downloaded from their web site), and built a program I've been working on, one which, years ago, was built for Windows using Cygwin by a different developer - Blitzed IRC Trivia (develop branch).
Under Win10/64, Cygwin finished a complete build with only the same 2 warnings (pertaining to Unused but set variables) that I receive when I make it on Linux. I've been developing and running it on Linux fine for a over a month. It connects to an IRC server and starts asking questions.
After I used Cygwin to make an exe, It would start, but fail the check when it got to L25 So it's breaking in the connect_to
function (link above). I re-checked my code several times, and finally installed gdb from the Cygwin package manager.
When I ran it through gdb, before getting to the breakpoint, I received an error that looked pretty serious regarding kernel32.dll. Unfortunately I didn't paste the output to a file so can't produce the exact error without rebooting to Windows.
But after I run it in ReactOS (in a VirtualBox on Debian 8), after I put the cygwin dlls in place, I get a dialog box
the procedure entry point CancelSynchronousIo could not be located in the dynamic link library kernel32.dll
I searched Google but haven't found anything concrete yet. My next step would be to try posting on the Cygwin mailing list.