1 /* Basic data types for Objective C.
2 Copyright (C) 1993, 1995, 1996, 2004, 2009,
3 2010 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
26 #ifndef __objc_INCLUDE_GNU
27 #define __objc_INCLUDE_GNU
36 Definition of the boolean type.
38 Compatibility note: the Apple/NeXT runtime defines a BOOL as a
39 'signed char'. The GNU runtime uses an 'unsigned char'.
41 Important: this could change and we could switch to 'typedef bool
42 BOOL' in the future. Do not depend on the type of BOOL.
45 typedef unsigned char BOOL;
50 /* The basic Objective-C types (SEL, Class, id) are defined as pointer
51 to opaque structures. The details of the structures are private to
52 the runtime and may potentially change from one version to the
56 /* A SEL (selector) represents an abstract method (in the
57 object-oriented sense) and includes all the details of how to
58 invoke the method (which means its name, arguments and return
59 types) but provides no implementation of its own. You can check
60 whether a class implements a selector or not, and if you have a
61 selector and know that the class implements it, you can use it to
62 call the method for an object in the class.
64 typedef const struct objc_selector *SEL;
65 #include "deprecated/struct_objc_selector.h"
67 /* A Class is a class (in the object-oriented sense). In Objective-C
68 there is the complication that each Class is an object itself, and
69 so belongs to a class too. This class that a class belongs to is
70 called its 'meta class'.
72 typedef struct objc_class *Class;
73 #include "deprecated/MetaClass.h"
74 #include "deprecated/struct_objc_class.h"
76 /* An 'id' is an object of an unknown class. The struct objc_object
77 is private and what you see here is only the beginning of the
78 struct. In theory, the fact that 'class_pointer' is public means
79 that if you have any object 'object', you can immediately get its
80 class by using '((id)object)->class_pointer', but this is not
81 recommended; you should use object_get_class(object) instead.
83 typedef struct objc_object
85 /* 'class_pointer' is the Class that the object belongs to. In case
86 of a Class object, this pointer points to the meta class. */
87 /* Note that the Apple/NeXT runtime calls this variable 'isa'.
88 TODO: Decide if we want to call it 'isa' too. TODO: Why not
89 simply hide this pointer and force users to use the proper API to
96 'IMP' is a C function that implements a method. When retrieving the
97 implementation of a method from the runtime, this is the type of the
98 pointer returned. The idea of the definition of IMP is to represent
99 a 'pointer to a general function taking an id, a SEL, followed by
100 other unspecified arguments'. You must always cast an IMP to a
101 pointer to a function taking the appropriate, specific types for
102 that function, before calling it - to make sure the appropriate
103 arguments are passed to it. The code generated by the compiler to
104 perform method calls automatically does this cast inside method
107 typedef id (*IMP)(id, SEL, ...);
109 /* 'nil' is the null object. Messages to nil do nothing and always
113 /* 'Nil' is the null class. Since classes are objects too, this is
114 actually the same object as 'nil' (and behaves in the same way),
115 but it has a type of Class, so it is good to use it instead of
116 'nil' if you are comparing a Class object to nil as it enables the
117 compiler to do some type-checking. */
120 #include "deprecated/STR.h"
122 /* TODO: Move the 'Protocol' declaration into objc/runtime.h. A
123 Protocol is simply an object, not a basic Objective-C type. The
124 Apple runtime defines Protocol in objc/runtime.h too, so it's good
125 to move it there for API compatibility.
128 /* A 'Protocol' is a formally defined list of selectors (normally
129 created using the @protocol Objective-C syntax). It is mostly used
130 at compile-time to check that classes implement all the methods
131 that they are supposed to. Protocols are also available in the
132 runtime system as Protocol objects.
135 /* Once we stop including the deprecated struct_objc_protocol.h
136 there is no reason to even define a 'struct objc_protocol'. As
137 all the structure details will be hidden, a Protocol basically is
138 simply an object (as it should be).
140 /* typedef struct objc_object Protocol; */
141 #include "deprecated/struct_objc_protocol.h"
146 /* Deprecated include - here temporarily, for backwards-compatibility
147 as reval_t, apply_t, arglist_t and objc_msg_lookup() used to be
151 /* Compatibility note: the Apple/NeXT runtime defines sel_getName(),
152 sel_registerName(), object_getClassName(), object_getIndexedIvars()
153 in this file while the GNU runtime defines them in runtime.h.
155 The reason the GNU runtime does not define them here is that they
156 are not basic Objective-C types (defined in this file), but are
157 part of the runtime API (defined in runtime.h).
164 #endif /* not __objc_INCLUDE_GNU */