Cygwin: A Free Win32 Porting Layer for UNIX Applications

8. Future Work

Standards conformance is becoming a more important focus. In the last release, all POSIX.1/90 calls are implemented except for mkfifo and setuid. X/Open Release 4 conformance may be a desirable goal, but we have not pursued this yet. While the current version of the library passes most of the NIST POSIX test suite with flying colors, it performs poorly with respect to mimicking the UNIX security model, so there is still room for improvement. When we consider how to implement the setuid functionality, we will also look into a secure alternative to the library's usage of the shared memory areas.

Cygwin does not yet support applications that use multiple Windows threads, even though the library itself is multi-threaded. We expect to address this shortcoming through the use of locks at strategic points in the DLL. It would also be desirable to implement support for POSIX threads.

Although Cygwin allows the GNU development tools that depend heavily on UNIX semantics to successfully run on Win32 hosts, it is not always desirable to use it. A program using a perfect implementation of the library would still incur a noticeable amount of overhead. As a result, an important future direction involves modifying the compiler so that it can optionally link against the Microsoft DLLs that ship with both Win32 operating systems, instead of Cygwin. This will give developers the ability to choose whether or not to use Cygwin on a per-program basis.