There are three ways you are probably reading this right now:
- On ObjFW's homepage, via Fossil's web interface
- On GitHub
- Via an editor or pager, by opening
README.mdfrom a clone or tarball
ObjFW is developed using Fossil, so if you are reading this on GitHub or any other place, you are most likely using a mirror.
- What is ObjFW?
- Installation
- License
- Releases
- Cloning the repository
- Building from source
- Writing your first application with ObjFW
- Documentation
- Bugs and feature requests
- Support and community
- Donating
- Thanks
- Commercial use
ObjFW is a portable, lightweight framework for the Objective-C language. It enables you to write an application in Objective-C that will run on any platform supported by ObjFW without having to worry about differences between operating systems or various frameworks you would otherwise need if you want to be portable.
It supports all modern Objective-C features when using Clang, but is also compatible with GCC ≥ 4.6 to allow maximum portability.
ObjFW is intentionally incompatible with Foundation. This has two reasons:
- GNUstep already provides a reimplementation of Foundation, which is only compatible to a certain degree. This means that a developer still needs to care about differences between frameworks if they want to be portable. The idea behind ObjFW is that a developer does not need to concern themselves with portability and making sure their code works with multiple frameworks: Instead, if it works it ObjFW on one platform, they can reasonably expect it to also work with ObjFW on another platform. ObjFW behaving differently on different operating systems (unless inevitable because it is a platform-specific part, like the Windows Registry) is considered a bug and will be fixed.
- Foundation predates a lot of modern Objective-C concepts. The most
prominent one is exceptions, which are only used in Foundation as a
replacement for
abort(). This results in cumbersome error handling, especially in initializers, which in Foundation only returnnilon error with no indication of what went wrong. It also means that the return of everyinitcall needs to be checked againstnil. But in the wild, nobody actually checks each and every return frominitagainstnil, leading to bugs. ObjFW fixes this by making exceptions a first class citizen.
ObjFW also comes with its own lightweight and extremely fast Objective-C runtime, which in real world use cases was found to be significantly faster than both GNU's and Apple's runtime.
ObjFW packages are available for various operating systems and can be installed as following:
| Operating System | Command |
|---|---|
| Alpine Linux | doas apk add objfw |
| CRUX | sudo prt-get depinst objfw |
| Fedora | sudo dnf install objfw |
| FreeBSD | sudo pkg install objfw |
| Haiku | pkgman install objfw |
| Haiku (gcc2h) | pkgman install objfw_x86 |
| macOS (Homebrew) | brew install objfw |
| macOS (pkgsrc) | cd $PKGSRCDIR/devel/objfw && make install |
| NetBSD | cd /usr/pkgsrc/devel/objfw && make install |
| OpenBSD | doas pkg_add objfw |
| OpenIndiana | sudo pkg install developer/objfw |
| Windows (MSYS2/CLANG64) | pacman -S mingw-w64-clang-x86_64-objfw |
| Windows (MSYS2/CLANGARM64) | pacman -S mingw-w64-clang-aarch64-objfw |
| Windows (MSYS2/UCRT64) | pacman -S mingw-w64-ucrt-x86_64-objfw |
| Windows (MSYS2/MINGW32) | pacman -S mingw-w64-i686-objfw |
If your operating system is not listed, you can build ObjFW from source.
ObjFW is released under the GNU Lesser General Public License version 3.0.
If this license does not work for you, contact me and we can find a solution.
Releases of ObjFW, as well as change logs and the accompanying documentation, can be found here.
ObjFW is developed in a Fossil repository, with automatic incremental exports to Git. This means you can either clone the Fossil repository or the Git repository - it does not make a huge difference. The main advantage of cloning the Fossil repository over cloning the Git repository is that you also get all the tickets, wiki pages, etc.
Clone the Fossil repository like this:
fossil clone https://objfw.nil.im
You can then use Fossil's web interface to browse the timeline, tickets, wiki pages, etc.:
cd objfw
fossil ui
In order to verify the signature of the currently checked out checkin, you can use:
fossil artifact current | gpg --verify
Please note that not all checkins are signed, as the signing key only resides on trusted systems. This means that checkins I perform on e.g. Windows are unsigned. However, usually it should not take long until there is another signed checkin. Alternatively, you can go back until the last signed checkin and review changes from there on.
To clone the Git repository, use the following:
git clone https://github.com/ObjFW/ObjFW
Git commits are not signed, so if you want to check the signature of an individual commit, branch head or tag, please use Fossil.
To build ObjFW from source and install it, just run the following commands:
./configure
make
make check
sudo make install
In case you checked out ObjFW from the Fossil or Git repository, you need to run the following command first:
./autogen.sh
When building for macOS or iOS, everything is built as a .framework by
default if --disable-shared has not been specified to ./configure. The
frameworks will end up in $PREFIX/Library/Frameworks.
To build for macOS, just follow the regular instructions above.
To build for iOS, follow the regular instructions, but instead of
./configure do something like this:
clang="xcrun --sdk iphoneos clang"
export OBJC="$clang -arch arm64e -arch arm64"
export OBJCPP="$clang -arch arm64e -E"
export IPHONEOS_DEPLOYMENT_TARGET="10.0"
./configure --prefix=/usr/local/ios --host=arm64-apple-darwin
To build for the iOS simulator, follow the regular instructions, but instead
of ./configure use something like this:
clang="xcrun --sdk iphonesimulator clang"
export OBJC="$clang -arch $(uname -m)"
export IPHONEOS_DEPLOYMENT_TARGET="10.0"
./configure --prefix=/usr/local/iossim --host=$(uname -m)-apple-darwin
To use the macOS framework in Xcode, you need to add the .frameworks to
your project and add the following flags to Other C Flags:
-fconstant-string-class=OFConstantString -fno-constant-cfstrings
Some versions of Xcode shipped with a version of Clang that ignores
-fconstant-string-class=OFConstantString. This will manifest in an error
like this:
OFAllocFailedException.m:94:10: error: cannot find interface declaration for
'NSConstantString'
return @"Allocating an object failed!";
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
Unfortunately, there is no workaround for this other than to upgrade/downgrade Xcode or to build upstream Clang yourself.
In particular, Xcode 11 Beta 1 to Beta 3 are known to be affected. While Xcode 11 Beta 4 to Xcode 11.3 work, the bug was unfortunately reintroduced in Xcode 11.4.1 and was only fixed in Xcode 12 Beta 1.
You can get older versions of Xcode here by clicking on "More" in the top-right corner.
Windows is only officially supported when following these instructions, as there are many MinGW versions that behave slightly differently and often cause problems.
The first thing to install is MSYS2 to provide a basic UNIX-like environment for Windows. Unfortunately, the binaries are not signed, so make sure you download it via HTTPS. However, packages you download and install via MSYS2 are cryptographically signed.
MSYS2 currently supports 7 different environments. All of them except for the one called just "MSYS" are supported, but which packages you need to install depends on the environment(s) you want to use. If you only want to target Windows 10 and newer, the CLANG64 and CLANG32 environments are the recommended ones.
For CLANG64, use:
pacman -Syu mingw-w64-clang-x86_64-clang \
mingw-w64-clang-x86_64-fossil \
mingw-w64-clang-x86_64-openssl
For CLANG32, use:
pacman -Syu mingw-w64-clang-i686-clang \
mingw-w64-clang-i686-fossil \
mingw-w64-clang-i686-openssl
For CLANGARM64, use (you need to use Fossil via another environment):
pacman -Syu mingw-w64-clang-aarch64-clang mingw-w64-clang-aarch64-openssl
For MINGW64, use:
pacman -Syu mingw-w64-x86_64-clang \
mingw-w64-x86_64-fossil \
mingw-w64-x86_64-openssl
For MINGW32, use:
pacman -Syu mingw-w64-i686-clang \
mingw-w64-i686-fossil \
mingw-w64-i686-openssl
For UCRT64, use:
pacman -Syu mingw-w64-ucrt-x86_64-clang \
mingw-w64-ucrt-x86_64-fossil \
mingw-w64-ucrt-x86_64-openssl
When using pacman to install the packages, pacman might tell you to close
the window. If it does so, close the window, restart MSYS2 and execute the
pacman command again.
There is nothing wrong with installing multiple environments, as MSYS2 has created shortcuts for each of them in your start menu. Just make sure to use the correct shortcut for the environment you want to use.
Finally, install a few more things that are common between all environments:
pacman -S autoconf automake make
Start the MSYS2 using the shortcut for the environment you want to use and check out ObjFW:
fossil clone https://objfw.nil.im
You can also download a release tarball if you want. Now cd to the newly
checked out repository and build and install it:
./autogen.sh && ./configure && make -j16 install
If everything was successful, you can now build projects using ObjFW for
Windows using the normal objfw-compile and friends.
Download and install devkitPro.
Follow the normal process, but instead of ./configure run:
./configure --host=arm-none-eabi --with-nds
Follow the normal process, but instead of ./configure run:
./configure --host=arm-none-eabi --with-3ds
Follow the normal process, but instead of ./configure run:
./configure --host=powerpc-eabi --with-wii
Install amiga-gcc. Then follow the
normal process, but instead of ./configure run:
./configure --host=m68k-amigaos
To create your first, empty application, you can use objfw-new:
objfw-new --app MyFirstApp
This creates a file MyFirstApp.m. The -[applicationDidFinishLaunching:]
method is called as soon as ObjFW finished all initialization. Use this as
the entry point to your own code. For example, you could add the following
line there to create a "Hello World":
[OFStdOut writeLine: @"Hello World!"];
You can compile your new app using objfw-compile:
objfw-compile -o MyFirstApp MyFirstApp.m
objfw-compile is a tool that allows building applications and libraries
using ObjFW without needing a full-blown build system. If you want to use
your own build system, you can get the necessary flags from objfw-config.
You can find the documentation for released versions of ObjFW here.
In order to build the documentation yourself (necessary to have documentation for trunk / master), you need to have Doxygen installed. Once installed, you can build the documentation from the root directory of the repository:
make docs
If you find any bugs or have feature requests, please file a new bug in the bug tracker.
Alternatively, feel free to send a mail to [email protected]!
If you have any questions about ObjFW or would like to talk to other ObjFW users, the following venues are available:
- The forum
- A Matrix room
- A Discord room, bridged to the Matrix room above
- A Telegram room, bridged to the Matrix room above
- A Slack room, bridged to the Matrix room above
- An IRC channel named
#objfwonirc.oftc.net(Web chat), bridged to the Matrix room above
Please don't hesitate to join any or all of those!
If you want to donate to ObjFW, you can read about possible ways to do so here.
- Thank you to Jonathan Neuschäfer for reviewing the entirety (all 84k LoC at the time) of ObjFW's codebase in 2017!
- Thank you to Hill Ma for donating an M1 Mac Mini to the project in 2022!
If for whatever reason the terms of GNU Lesser General Public License version 3.0 don't work for you, a proprietary license for ObjFW including support is available upon request. Just write a mail to [email protected] and we can find a reasonable solution for both parties.
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