mulle-objc-runtime

⏩ A fast, portable Objective-C runtime written 100% in C11

A portable Objective-C runtime written in C11. No Assembler required. It follows the Apple "Objective-C 1 Runtime" and adds many features from "Objective-C 2.0", but the runtime function calls are completely different. It is designed to be suitable for massive multi-threading.

Release Version	Release Notes
	RELEASENOTES

API

Data structure	Description
_mulle_objc_class	Deal with Classes
_mulle_objc_ivar et al.	Instance variables
_mulle_objc_loadinfo	Install Classes, Categories, Methods, Strings into the runtime
_mulle_objc_method et al.	Deal with Methods
_mulle_objc_object et al.	Deal with Instances
_mulle_objc_property et al.	Handle Properties
_mulle_objc_universe	Work with the runtime universe

Function type	Description
Global Functions	Global functions and conveniences
Exceptions	Raising exceptions
Vararg extensions	Dealing with variable arguments

Usage

If you haven't used an Objective-C runtime before, it is useful to get to know the much better documented "Mac OS X Objective-C 1.0" runtime first. Intro to the Objective-C Runtime could be a good starting point.

C Caveat

It you use .c files that include <mulle-objc-runtime/mulle-objc-runtime.h> make sure that you compile with __MULLE_OBJC_TPS__, __MULLE_OBJC_NO_TPS__ __MULLE_OBJC_FCS__ __MULLE_OBJC_NO_FCS__ as defined when compiling the runtime. Since C-only compilations do not emit runtime information, mismatches can not be checked by the runtime. Easy fix: rename .c to .m and use mulle-clang

What's so different ?

• Runtime objects (like classes and selectors) are not referenced by name, but by a unique ID. No special linker action required.

• Parameters outside of self and _cmd are passed via _param, a single pointer to a struct. This simplifies a lot of code, especially forwarding code. Return values are also returned with the same struct. Optimizations are done for simple methods with only none or one parameter and none or one return value.

• It uses inlineable method calls for superior performance. The user can specify "fast" classes and "fast" methods for extra speed in performance critical cases.

• retain/release semantics are built in. These are non-overridable, which makes them a lot faster.

• isa is not part of the instance, but instead prefixed to the instance.

• Protocol as a type and an object does not exist anymore. Instead there is PROTOCOL which is basically the same as SEL and has compiler support.

• No global lock, except when loading code. The runtime in normal operation only locks during +initialize on a per class basis.

• Protections against the fragile base class problem

• Multiple runtimes can coexist in differently named "universes".

Articles

These articles give you some background about the mulle-objc runtime:

1. mulle-objc: a new Objective-C runtime
2. mulle-objc: a meta calling convention
3. mulle-objc: removing superflous ifs
4. mulle-objc: inlined messaging
5. mulle-objc: some research about selectors
6. mulle-objc: hashes for classes, selectors and protocols
7. mulle_objc: object layout, retain counting, finalize
8. mulle_objc: inheriting methods from protocols
9. mulle_objc: present and absent language features
10. mulle_objc: the trouble with @property
11. mulle_objc: ivar layout with @property
12. mulle_objc: technically speaking
13. mulle-clang, technically speaking
14. mulle-objc-runtime, technically speaking
15. MulleFoundation, technically speaking

If something is unclear, feel free to contact the author.

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Requirements

Requirement	Release Version	Description
mulle-core		🌋 Almagamated library of mulle-core and mulle-c
mulle-atinit		🤱🏼 Compatibility library for deterministic initializers
mulle-atexit		👼 Compatibility library to fix atexit

Add

Add as an individual component

Use mulle-sde to add mulle-objc-runtime to your project:

mulle-sde add github:mulle-objc/mulle-objc-runtime

To only add the sources of mulle-objc-runtime with dependency sources use clib:

clib install --out src/mulle-objc mulle-objc/mulle-objc-runtime

Add -isystem src/mulle-objc to your CFLAGS and compile all the sources that were downloaded with your project.

Install

Install with mulle-sde

Use mulle-sde to build and install mulle-objc-runtime and all dependencies:

mulle-sde install --prefix /usr/local \
   https://github.com/mulle-objc/mulle-objc-runtime/archive/latest.tar.gz

Manual Installation

Install the Requirements and then install mulle-objc-runtime with cmake:

cmake -B build \
      -DCMAKE_INSTALL_PREFIX=/usr/local \
      -DCMAKE_PREFIX_PATH=/usr/local \
      -DCMAKE_BUILD_TYPE=Release &&
cmake --build build --config Release &&
cmake --install build --config Release

Author

Nat! for Mulle kybernetiK