winpty/README.md

# winpty

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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.

## Supported Windows versions

winpty runs on Windows XP through Windows 10, including server versions.  It
can be compiled into either 32-bit or 64-bit binaries.

## Cygwin/MSYS adapter (`winpty.exe`)

### 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 `winpty.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 `winpty.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The MinGW compiler (e.g. from the `mingw-gcc-g++` package) is no longer
maintained and is too buggy.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`

MSYS2 provides three start menu shortcuts for starting MSYS2:

* MinGW-w64 Win32 Shell
* MinGW-w64 Win64 Shell
* MSYS2 Shell

To build winpty, use the MinGW-w64 {Win32,Win64} shortcut of the architecture
matching MSYS2.  These shortcuts will put the g++ compiler from the
`{mingw32,mingw64}/mingw-w64-{i686,x86_64}-gcc` packages into the `PATH`.

Alternatively, instead of installing `mingw32/mingw-w64-i686-gcc` or
`mingw64/mingw-w64-x86_64-gcc`, install the `mingw-w64-cross-gcc` and
`mingw-w64-cross-crt-git` packages.  These packages install cross-compilers
into `/opt/bin`, and then any of the three shortcuts will work.

### Building the Unix adapter

In the project directory, run `./configure`, then `make`, then `make install`.
By default, winpty is installed into `/usr/local`.  Pass `PREFIX=<path>` to
`make install` to override this default.

### Using the Unix adapter

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

    $ winpty powershell
    Windows PowerShell
    Copyright (C) 2009 Microsoft Corporation. All rights reserved.

    PS C:\rprichard\proj\winpty> 10 + 20
    30
    PS C:\rprichard\proj\winpty> exit

## Embedding winpty / MSVC compilation

See `src/include/winpty.h` for the prototypes of functions exported by
`winpty.dll`.

Only the `winpty.exe` binary uses Cygwin; all the other binaries work without
it and can be compiled with either MinGW or MSVC.  To compile using MSVC,
download gyp and run `gyp -I configurations.gypi` in the `src` subdirectory.
This will generate a `winpty.sln` and associated project files.  See the
`src/winpty.gyp` and `src/configurations.gypi` files for notes on dealing with
MSVC versions and different architectures.

Compiling winpty with MSVC currently requires MSVC 2013 or newer.

## 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
   `winpty.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.