gcc/libobjc/objc/objc.h
Nicola Pero 4c341bf5b7 Added comments to the definition of IMP
From-SVN: r57072
2002-09-12 17:28:47 +00:00

166 lines
5.6 KiB
Objective-C

/* Basic data types for Objective C.
Copyright (C) 1993, 1995, 1996 Free Software Foundation, Inc.
This file is part of GNU CC.
GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* As a special exception, if you link this library with files
compiled with GCC to produce an executable, this does not cause
the resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why
the executable file might be covered by the GNU General Public License. */
#ifndef __objc_INCLUDE_GNU
#define __objc_INCLUDE_GNU
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>
/*
** Definition of the boolean type.
*/
#ifdef __vxworks
typedef int BOOL;
#else
typedef unsigned char BOOL;
#endif
#define YES (BOOL)1
#define NO (BOOL)0
/*
** Definition of a selector. Selectors themselves are not unique, but
** the sel_id is a unique identifier.
*/
typedef const struct objc_selector
{
void *sel_id;
const char *sel_types;
} *SEL;
inline static BOOL
sel_eq (SEL s1, SEL s2)
{
if (s1 == 0 || s2 == 0)
return s1 == s2;
else
return s1->sel_id == s2->sel_id;
}
/*
** ObjC uses this typedef for untyped instances.
*/
typedef struct objc_object {
struct objc_class* class_pointer;
} *id;
/*
** Definition of method type. When retrieving the implementation of a
** method, this is 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, ...);
/*
** More simple types...
*/
#define nil (id)0 /* id of Nil instance */
#define Nil (Class)0 /* id of Nil class */
typedef char *STR; /* String alias */
/*
** The compiler generates one of these structures for each class.
**
** This structure is the definition for classes.
**
** This structure is generated by the compiler in the executable and used by
** the run-time during normal messaging operations. Therefore some members
** change type. The compiler generates "char* const" and places a string in
** the following member variables: super_class.
*/
typedef struct objc_class *MetaClass;
typedef struct objc_class *Class;
struct objc_class {
MetaClass class_pointer; /* Pointer to the class's
meta class. */
struct objc_class* super_class; /* Pointer to the super
class. NULL for class
Object. */
const char* name; /* Name of the class. */
long version; /* Unknown. */
unsigned long info; /* Bit mask. See class masks
defined above. */
long instance_size; /* Size in bytes of the class.
The sum of the class
definition and all super
class definitions. */
struct objc_ivar_list* ivars; /* Pointer to a structure that
describes the instance
variables in the class
definition. NULL indicates
no instance variables. Does
not include super class
variables. */
struct objc_method_list* methods; /* Linked list of instance
methods defined for the
class. */
struct sarray * dtable; /* Pointer to instance
method dispatch table. */
struct objc_class* subclass_list; /* Subclasses */
struct objc_class* sibling_class;
struct objc_protocol_list *protocols; /* Protocols conformed to */
void* gc_object_type;
};
#ifndef __OBJC__
typedef struct objc_protocol {
struct objc_class* class_pointer;
char *protocol_name;
struct objc_protocol_list *protocol_list;
struct objc_method_description_list *instance_methods, *class_methods;
} Protocol;
#else /* __OBJC__ */
@class Protocol;
#endif
typedef void* retval_t; /* return value */
typedef void(*apply_t)(void); /* function pointer */
typedef union {
char *arg_ptr;
char arg_regs[sizeof (char*)];
} *arglist_t; /* argument frame */
IMP objc_msg_lookup(id receiver, SEL op);
#ifdef __cplusplus
}
#endif
#endif /* not __objc_INCLUDE_GNU */