There are three ways you are probably reading this right now:

• On ObjFW's homepage, via Fossil
• On GitHub
• Via an editor or pager, by opening

  README.md

  from a checkout 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.

Table of Contents

• What is ObjFW?
• License
• Releases
• Cloning the repository
• Installation
  • macOS and iOS
    • Building as a framework
    • Using the macOS or iOS framework in Xcode
    • Broken Xcode versions
  • Windows
    • Getting MSYS2
    • Updating MSYS2
    • Installing MinGW-w64 using MSYS2
    • Getting, building and installing ObjFW
  • Nintendo DS, Nintendo 3DS and Wii
    • Nintendo DS
    • Nintendo 3DS
    • Wii
  • Amiga
• Writing your first application with ObjFW
• Documentation
• Bugs and feature requests
• Support and community
• Commercial use

What is ObjFW?

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 portablility 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 return

  nil

  on error with no indication of what went wrong. It also means that the return of every

  init

  call needs to be checked against

  nil

  . But in the wild, nobody actually checks each and every return from

  init

  against

  nil

  , 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.

License

ObjFW is released under three licenses:

• QPL
• GPLv2
• GPLv3

The QPL allows you to use ObjFW in any open source project. Because the GPL does not allow using code under any other license, ObjFW is also available under the GPLv2 and GPLv3 to allow GPL-licensed projects to use ObjFW.

You can pick under which of those three licenses you want to use ObjFW. If none of them work for you, contact me and we can find a solution.

Releases

Releases of ObjFW, as well as changelogs and the accompanying documentation can be found here.

Cloning the repository

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.

Fossil

Clone the Fossil repository like this:

$ fossil clone https://objfw.nil.im objfw.fossil
$ mkdir objfw && cd objfw
$ fossil open ../objfw.fossil

You can then use Fossil's web interface to browse the timeline, tickets, wiki pages, etc.:

$ fossil ui

It's also possible to open the same local repository multiple times, so that you have multiple working directories all backed by the same local repository.

In order to verify the signature of the currently checked out checkin, you can use:

$ fossil artifact current | gpg --verify

Git

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.

Installation

To install ObjFW, just run the following commands:

$ ./configure
$ make
$ make install

In case you checked out ObjFW from the Fossil or Git repository, you need to run the following command first:

$ ./autogen.sh

macOS and iOS

Building as a framework

When building for macOS or iOS, everything is built as a

.framework

--disable-shared

configure

To build for iOS, use something like this:

$ clang="clang -isysroot $(xcrun --sdk iphoneos --show-sdk-path)"
$ export OBJC="$clang -arch armv7 -arch arm64"
$ export OBJCPP="$clang -arch armv7 -E"
$ export IPHONEOS_DEPLOYMENT_TARGET="9.0"
$ ./configure --prefix=/usr/local/ios --host=arm-apple-darwin

To build for the iOS simulator, use something like this:

$ clang="clang -isysroot $(xcrun --sdk iphonesimulator --show-sdk-path)"
$ export OBJC="$clang -arch i386 -arch x86_64"
$ export OBJCPP="$clang -arch i386 -E"
$ export IPHONEOS_DEPLOYMENT_TARGET="9.0"
$ ./configure --prefix=/usr/local/iossim --host=i386-apple-darwin

Using the macOS or iOS framework in Xcode

To use the macOS framework in Xcode, you need to add the

.framework

Other C Flags

-fconstant-string-class=OFConstantString -fno-constant-cfstrings

Broken Xcode versions

Some versions of Xcode shipped with a version of Clang that ignores

-fconstant-string-class=OFConstantString

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

Windows is only officially supported when following these instructions, as there are many MinGW versions that behave slightly differently and often cause problems.

Getting MSYS2

The first thing to install is MSYS2 to provide a basic UNIX-like environment for Windows. Unfortunately, the binaries are not signed and there is no way to verify their integrity, so only download this from a trusted connection. Everything else you will download using MSYS2 later will be cryptographically signed.

Updating MSYS2

The first thing to do is updating MSYS2. It is important to update things in a certain order, as

pacman

First, update the mirror list:

$ pacman -Sy pacman-mirrors

Then proceed to update the

msys2-runtime

bash

pacman

$ pacman -S msys2-runtime bash pacman mintty

Now close the current window and restart MSYS2, as the current window is now defunct. In a new MSYS2 window, update the rest of MSYS2:

$ pacman -Su

Now you have a fully updated MSYS2. Whenever you want to update MSYS2, proceed in this order. Notice that the first

pacman

-y

Installing MinGW-w64 using MSYS2

Now it's time to install MinGW-w64. If you want to build 32 bit binaries:

$ pacman -S mingw-w64-i686-clang mingw-w64-i686-gcc-objc

For 64 bit binaries:

$ pacman -S mingw-w64-x86_64-clang mingw-w64-x86_64-gcc-objc

There is nothing wrong with installing them both, as MSYS2 has created two entries in your start menu:

MinGW-w64 Win32 Shell

MinGW-w64 Win64 Shell

Finally, install a few more things needed to build ObjFW:

$ pacman -S autoconf automake fossil make

Getting, building and installing ObjFW

Start the MinGW-w64 Win32 or Win64 Shell (depening on what version you want to build - do not use the MSYS2 Shell shortcut, but use the MinGW-w64 Win32 or Win64 Shell shortcut instead!) and check out ObjFW:

$ fossil clone https://objfw.nil.im objfw.fossil
$ mkdir objfw && cd objfw
$ fossil open ../objfw.fossil

You can also download a release tarball if you want. Now go to the newly checked out repository and build and install it:

$ ./autogen.sh && ./configure && make -j16 install

If everything was successfully, you can now build projects using ObjFW for Windows using the normal

objfw-compile

Nintendo DS, Nintendo 3DS and Wii

Download and install devkitPro.

Nintendo DS

Follow the normal process, but instead of

./configure

$ ./configure --host=arm-none-eabi --with-nds

Nintendo 3DS

Follow the normal process, but instead of

./configure

$ ./configure --host=arm-none-eabi --with-3ds

Wii

Follow the normal process, but instead of

./configure

$ ./configure --host=powerpc-eabi --with-wii

Amiga

Install amiga-gcc. Then follow the normal process, but instead of

./configure

$ ./configure --host=m68k-amigaos

Writing your first application with ObjFW

To create your first, empty application, you can use

objfw-new

$ objfw-new app MyFirstApp

This creates a file

MyFirstApp.m

-[applicationDidFinishLaunching]

[of_stdout writeLine: @"Hello World!"];

You can compile your new app using

objfw-compile

$ objfw-compile -o MyFirstApp MyFirstApp.m

objfw-compile

objfw-config

Documentation

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

Bugs and feature requests

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]!

Support and community

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
• An IRC channel named

  #objfw

  on

  irc.oftc.net

  (Web chat), bridged to the Matrix room above
• A Slack channel, bridged to the Matrix room above
• A Discord channel, bridged to the Matrix room above
• A Telegram room, bridged to the Matrix room above
• A Gitter room, bridged to the Matrix room above

Please don't hesitate to join any or all of those!

Commercial use

If for whatever reason neither the terms of the QPL nor those of the GPL 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.