8.1.1 Modern GNU Objective-C Runtime API ¶
The GNU Objective-C runtime provides an API which is similar to the
one provided by the “Objective-C 2.0” Apple/NeXT Objective-C
runtime. The API is documented in the public header files of the GNU
Objective-C runtime:
- objc/objc.h: this is the basic Objective-C header file,
defining the basic Objective-C types such as
id
, Class
and BOOL
. You have to include this header to do almost
anything with Objective-C.
- objc/runtime.h: this header declares most of the public runtime
API functions allowing you to inspect and manipulate the Objective-C
runtime data structures. These functions are fairly standardized
across Objective-C runtimes and are almost identical to the Apple/NeXT
Objective-C runtime ones. It does not declare functions in some
specialized areas (constructing and forwarding message invocations,
threading) which are in the other headers below. You have to include
objc/objc.h and objc/runtime.h to use any of the
functions, such as
class_getName()
, declared in
objc/runtime.h.
- objc/message.h: this header declares public functions used to
construct, deconstruct and forward message invocations. Because
messaging is done in quite a different way on different runtimes,
functions in this header are specific to the GNU Objective-C runtime
implementation.
- objc/objc-exception.h: this header declares some public
functions related to Objective-C exceptions. For example functions in
this header allow you to throw an Objective-C exception from plain
C/C++ code.
- objc/objc-sync.h: this header declares some public functions
related to the Objective-C
@synchronized()
syntax, allowing
you to emulate an Objective-C @synchronized()
block in plain
C/C++ code.
- objc/thr.h: this header declares a public runtime API threading
layer that is only provided by the GNU Objective-C runtime. It
declares functions such as
objc_mutex_lock()
, which provide a
platform-independent set of threading functions.
The header files contain detailed documentation for each function in
the GNU Objective-C runtime API.