Designed and implemented by Robin Rowe, libunistd is a lightweight Windows POSIX library that enables typical Linux C/C++ code to build in Windows Microsoft Visual Studio. If you're looking for a Windows POSIX compatibility library that is much lighter than Cygwin, you've come to the right place. Most of the Libunistd library is header-only. However, a few functions do have cpp files. Use the provided cmake file to link those, or cheat by dragging a few cpp files from libunistd into your Visual Studio project.
Libunistd provides standard BSD sockets, pthreads and message queue APIs in Windows. It supports every common Linux call, except one. The call fork() is deliberately not supported. Use C++ standard threads or POSIX pthreads instead.
Usage: Set the include path in your VC++ project to include the directory libunistd/unistd (where the unistd.h file is). In any Linux code you have that won't compile in VC++, include the following at top of your header file:
#include <unistd.h>
Doing this will include the magic to make basic Linux APIs work in Windows. Because unistd.h exists in Linux as a standard header file, making this change for Windows will not break Linux code. Avoid conditionally defining _WIN32 ugliness in your code. Simply write C++ code as you would for Linux, and it should build in Visual Studio (2017 or 2015).
Libunisd is more than unistd.h. It implements many other header files that are POSIX standards, including pthreads.h. When porting your Linux program to Windows for the first time, you may have to include more POSIX headers in your Linux code. In Linux, some standard headers include other standard header files. As a result, sometimes Linux code will compile that's not stictly legal, that hasn't explicitly included all necessary header files. If you port Linux code to FreeBSD or Mac OS X, you have already encountered this, that the compiler sometimes objects to unknown POSIX functions. The solution is simple. Look up in the Linux man page the "unknown" function and include all the header files that the Linux man page says it requires.
Libunistd has some additional small libraries that are not POSIX, but are very useful to those of us developing cross-platform code. Libunistd has no dependencies on these. Use them if you wish.
-
Portable: System classes, such as StdFile that encapsulates the standard FILE* C API into a C++ class with constructors and destructors.
-
Qdecoder: A small HTTP library created elsewhere.
-
Sqlite: A small SQL library created elsewhere.
-
xxHash: A small hash library created elsewhere.
Open Source MIT/BSD. In other words, you may do pretty much whatever you want with libunistd, not copyleft GNU. Similar for Qdecoder, Sqlite and xxHash, however you should check their license terms yourself as libunistd is not the owner of these other open source libraries.
Robin.Rowe@cinepaint.org Hollywood, California 310-359-8796
Libunistd was originally created to port Linux CinePaint to Windows in 2002. CinePaint is an open source HDR paint application used in making motion pictures, including the Harry Potter and Lord of the Rings films. Libunistd later moved from SourceForge to github and has been continuously improved, with more and more BSD and System V calls added.
Libunistd is being used for safety-critical Linux embedded systems. Not to deliver a Windows build on an embedded system, rather for testing and QA of the same embedded system codebase in Windows with access to the superb Microsoft Visual Studio debugger and its excellent static code checker that detects memory overruns.
To maintain separate open source and commercial git projects, here's how I set my open source local user info...
git config user.name "Robin Rowe"
git config user.email "Robin.Rowe@cinepaint.org"
git commit --amend --reset-author