/* Basic data types for Objective C.   Copyright (C) 1993-2026 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 3, or (at your option)any later version. GCC is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See theGNU General Public License for more details. Under Section 7 of GPL version 3, you are granted additionalpermissions described in the GCC Runtime Library Exception, version3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License anda copy of the GCC Runtime Library Exception along with this program;see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see<http://www.gnu.org/licenses/>.  */ #ifndef __objc_INCLUDE_GNU#define __objc_INCLUDE_GNU /* This file contains the definition of the basic types used by the   Objective-C language.  It needs to be included to do almost   anything with Objective-C.  */ #ifdef __cplusplusextern "C" {#endif #include <stddef.h> /* The current version of the GNU Objective-C Runtime library in   compressed ISO date format.  This should be updated any time a new   version is released with changes to the public API (there is no   need to update it if there were no API changes since the previous   release).  This macro is only defined starting with the GNU   Objective-C Runtime shipped with GCC 4.6.0.  If it is not defined,   it is either an older version of the runtime, or another runtime.  */#define __GNU_LIBOBJC__ 20110608 /* Definition of the boolean type.    Compatibility note: the Apple/NeXT runtime defines a BOOL as a   'signed char'.  The GNU runtime uses an 'unsigned char'.    Important: this could change and we could switch to 'typedef bool   BOOL' in the future.  Do not depend on the type of BOOL.  */#undef BOOLtypedef unsigned char  BOOL; #define YES   (BOOL)1#define NO    (BOOL)0 /* The basic Objective-C types (SEL, Class, id) are defined as pointer   to opaque structures.  The details of the structures are private to   the runtime and may potentially change from one version to the   other.  */ /* A SEL (selector) represents an abstract method (in the   object-oriented sense) and includes all the details of how to   invoke the method (which means its name, arguments and return   types) but provides no implementation of its own.  You can check   whether a class implements a selector or not, and if you have a   selector and know that the class implements it, you can use it to   call the method for an object in the class.  */typedef const struct objc_selector *SEL; /* A Class is a class (in the object-oriented sense).  In Objective-C   there is the complication that each Class is an object itself, and   so belongs to a class too.  This class that a class belongs to is   called its 'meta class'.  */typedef struct objc_class *Class; /* An 'id' is an object of an unknown class.  The way the object data   is stored inside the object is private and what you see here is   only the beginning of the actual struct.  The first field is always   a pointer to the Class that the object belongs to.  */typedef struct objc_object{  /* 'class_pointer' is the Class that the object belongs to.  In case     of a Class object, this pointer points to the meta class.      Compatibility Note: The Apple/NeXT runtime calls this field     'isa'.  To access this field, use object_getClass() from     runtime.h, which is an inline function so does not add any     overhead and is also portable to other runtimes.  */  Class class_pointer;} *id; /* 'IMP' is a C function that implements a method.  When retrieving   the implementation of a method from the runtime, this is the type   of the pointer returned.  The idea of the definition of IMP is to   represent a 'pointer to a general function taking an id, a SEL,   followed by other unspecified arguments'.  You must always cast an   IMP to a pointer to a function taking the appropriate, specific   types for that function, before calling it - to make sure the   appropriate arguments are passed to it.  The code generated by the   compiler to perform method calls automatically does this cast   inside method calls.  */typedef id (*IMP)(id, SEL, ...);  /* 'nil' is the null object.  Messages to nil do nothing and always   return 0.  */#define nil (id)0 /* 'Nil' is the null class.  Since classes are objects too, this is   actually the same object as 'nil' (and behaves in the same way),   but it has a type of Class, so it is good to use it instead of   'nil' if you are comparing a Class object to nil as it enables the   compiler to do some type-checking.  */#define Nil (Class)0 /* TODO: Move the 'Protocol' declaration into objc/runtime.h.  A   Protocol is simply an object, not a basic Objective-C type.  The   Apple runtime defines Protocol in objc/runtime.h too, so it's good   to move it there for API compatibility.  */ /* A 'Protocol' is a formally defined list of selectors (normally   created using the @protocol Objective-C syntax).  It is mostly used   at compile-time to check that classes implement all the methods   that they are supposed to.  Protocols are also available in the   runtime system as Protocol objects.  */#ifndef __OBJC__  /* Once we stop including the deprecated struct_objc_protocol.h     there is no reason to even define a 'struct objc_protocol'.  As     all the structure details will be hidden, a Protocol basically is     simply an object (as it should be).  */  typedef struct objc_object Protocol;#else /* __OBJC__ */  @class Protocol;#endif  /* Compatibility note: the Apple/NeXT runtime defines sel_getName(),   sel_registerName(), object_getClassName(), object_getIndexedIvars()   in this file while the GNU runtime defines them in runtime.h.    The reason the GNU runtime does not define them here is that they   are not basic Objective-C types (defined in this file), but are   part of the runtime API (defined in runtime.h).  */ #ifdef __cplusplus}#endif #endif /* not __objc_INCLUDE_GNU */