winpty

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.

Prerequisites

You need the following to build winpty:

• A Cygwin or MSYS installation
• GNU make
• A MinGW g++ toolchain capable of compiling C++11 code to build winpty.dll and winpty-agent.exe
• A g++ toolchain targeting Cygwin or MSYS to build console.exe

Winpty requires two g++ toolchains as it is split into two parts. The winpty.dll and winpty-agent.exe binaries 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 generally acceptable.

Cygwin packages

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

• Either mingw64-i686-gcc-g++ or mingw64-x86_64-gcc-g++. Select the appropriate compiler for your CPU architecture.
• gcc-g++
• make

As of this writing (2016-01-23), only the MinGW-w64 compiler is acceptable. The MinGW compiler (e.g. from the mingw-gcc-g++ package) is no longer maintained and is too buggy.

MSYS packages

For the original MSYS, use the mingw-get tool (MinGW Installation Manager), and select at least these components:

• mingw-developer-toolkit
• mingw32-base
• mingw32-gcc-g++
• msys-base
• msys-system-builder

When running ./configure, make sure that mingw32-g++ is in your PATH. It will be in the C:\MinGW\bin directory.

MSYS2 packages

For MSYS2, use pacman and install at least these packages:

• msys/gcc
• mingw32/mingw-w64-i686-gcc or mingw64/mingw-w64-x86_64-gcc. Select the appropriate compiler for your CPU architecture.
• make

Build

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

This will produce three binaries:

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

Using the Unix adapter

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()
$

Debugging winpty

winpty comes with a tool for collecting timestamped debugging output. To use it:

1. Run winpty-debugserver.exe on the same computer as winpty.
2. Set the WINPTY_DEBUG environment variable to trace for the console.exe process and/or the process using libwinpty.dll.

winpty also recognizes a WINPTY_SHOW_CONSOLE environment variable. Set it to 1 to prevent winpty from hiding the console window.

Copyright

This project is distributed under the MIT license (see the LICENSE file in the project root).

By submitting a pull request for this project, you agree to license your contribution under the MIT license to this project.