winpty is a Windows software package providing an interface similar to a Unix pty-master for communicating with Windows console programs. The package consists of a library (libwinpty) and a tool for Cygwin and MSYS for running Windows console programs in a Cygwin/MSYS pty.

The software works by starting the winpty-agent.exe process with a new, hidden console window, which bridges between the console API and terminal input/output escape codes. It polls the hidden console's screen buffer for changes and generates a corresponding stream of output.

The Unix adapter allows running Windows console programs (e.g. CMD, PowerShell, IronPython, etc.) under mintty or Cygwin's sshd with properly-functioning input (e.g. arrow and function keys) and output (e.g. line buffering). The library could be also useful for writing a non-Cygwin SSH server.

You need the following to build winpty:

• A Cygwin or MSYS installation
• GNU make
• A MinGW 32-bit g++ toolchain, v4 or later, to build winpty.dll and winpty-agent.exe
• A g++ toolchain targeting Cygwin or MSYS, v3 or later, to build console.exe

Winpty requires two g++ toolchains as it is split into two parts. The binaries winpty.dll and winpty-agent.exe interface with the native Windows command prompt window so they are compiled with the native MinGW toolchain. The console.exe binary interfaces with the MSYS/Cygwin terminal so it is compiled with the MSYS/Cygwin toolchain.

MinGW appears to be split into two distributions -- MinGW (creates 32-bit binaries) and MinGW-w64 (creates both 32-bit and 64-bit binaries). Either one is acceptable, but the compiler must be v4 or later and produce 32-bit binaries.

The default g++ compiler for Cygwin targets Cygwin itself, but Cygwin also packages MinGW compilers from both the MinGW and MinGW-w64 projects. As of this writing, the necessary packages are:

• Either mingw-gcc-g++ or mingw64-i686-gcc-g++ (but not mingw64-x86_64-gcc-g++)
• gcc4-g++

The default g++ compiler for MinGW targets native Windows, but the MinGW project also packages compilers to target the MSYS environment itself. The required packages are:

• mingw32-make
• g++
• msys-dvlpr

In the project directory, run ./configure, then make.

This will produce three binaries:

• build/winpty.dll
• build/winpty-agent.exe
• build/console.exe

To run a Windows console program in mintty or Cygwin sshd, prepend console.exe to the command-line:

$ build/console.exe c:/Python27/python.exe
Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> 10 + 20
30
>>> exit()
$