It is certainly possible to call code in a dll built with one compiler, from code compiled with a different compiler.

For example, calling any of the system modules (which are probably mostly built with one MS C or C++ compiler or other) from programs compiled with Borland's C or Digital Mars C++ works fine. Indeed, so does callng those same system DLLs from programs built with DMD or Haskell or Ocaml or Erlang or Clean or Perl or Ruby.

It depends very much upon how the DLL is built and whether all it's runtime dependancies are added to the DLL (or derived from other DLLs), or not. I agree that it will not always work, and you are much safer sticking with a single compiler.

The biggest danger is that you will get mismatched Perl components. If you attempted to use a module built for Cygwin Perl 5.6.x in conjunction with AS perl 5.8.x, it will almost certainly fail immediately, If both Perl's are the same version, you are less likely to encounter problems.

I wouldn't use such cross-built DLLs for any critical purpose, but as a stop gap measure to trying something out, I might consider it.