Cygwin/MSYS support

[RyanGlScott]

Currently, the size command yields Nothing on a Cygwin or MSYS terminal on Windows, which is kind of unfortunate. As a workaround, I use the process library to call stty size if c_GetConsoleScreenBufferInfo fails. stty is a part of coreutils, so it should be installed by default on Cygwin and MSYS (it worked when I tried it on my installations, at least.)

An alternative would be calling tput lines and tput cols processes, but that requires ncurses, which isn't installed by default on recent versions of Cygwin (plus, it kind of defeats the point of this library in the first place).

[dmalikov]

@RyanGlScott could you please specify a version of ghc that you're running inside a Cygwin?

[RyanGlScott]

GHC 7.10.1 (although the GHC version shouldn't matter, since the issue is inherently related to how mintty works, I believe).

[supki]

First off, I'm very much in favor of adding Cygwin support. There's a couple of questions I have about the implementation though, and without any Windows machines around I can't answer them myself.

Can we use the TIOCGWINSZ ioctl like the POSIX implementation does? Failing that, is it possible to replicate whatever magic stty size does without shelling out to it? I don't expect the way to get tty columns/lines number to change any time soon so even a copy of an existing working solution looks better than relying on an external binary.

[RyanGlScott]

Unfortunately, I don't think that the version of MinGW that GHC ships comes with sys/ioctl.h, since I can't compile System.Console.Terminal.Size on Windows (which isn't surprising, given that Win32 doesn't have an ioctl equivalent, at least according to the Cygwin developers):

$ hsc2hs.exe .\Posix.hsc
Posix.hsc:20:23: fatal error: sys/ioctl.h: No such file or directory
compilation terminated.
compiling .\Posix_hsc_make.c failed (exit code 1)

I'll try to look at the source code of stty to see if it can be ported directly to Haskell.

[RyanGlScott]

Hm, my searching didn't come up anything promising. Cygwin and MSYS's implementation of stty uses ioctl underneath the surface. However, I don't think the version of MinGW that ships with Windows GHC includes this, so unless we tell users to link against Cygwin/MSYS-specific versions of ioctl, there's not a whole lot one can do about this problem.

[supki]

Alright.

[supki]

Pulled (6176787), thanks!

[supki]

On Hackage as 0.3.2.