xref: /illumos-gate/usr/src/uts/common/sys/va_impl.h (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved	*/
24 
25 
26 /*
27  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28  * Use is subject to license terms.
29  */
30 
31 #ifndef	_SYS_VA_IMPL_H
32 #define	_SYS_VA_IMPL_H
33 
34 #pragma ident	"%Z%%M%	%I%	%E% SMI"
35 
36 /*
37  * An application should not include this header directly.  Instead it
38  * should be included only through the inclusion of other Sun headers,
39  * specifically <stdarg.h> and <varargs.h>.
40  *
41  * This header serves two purposes.
42  *
43  * First, it provides a common set of definitions that implementations
44  * of the various standards for variable argument lists may use.  These
45  * various standards are implemented in <varargs.h>, <stdarg.h>,
46  * <iso/stdarg_iso.h>, <iso/stdarg_c99.h>, and <sys/varargs.h>.
47  *
48  * Second, it provides varying implementations of the common definitions,
49  * depending upon the compiler.
50  */
51 
52 /*
53  * The common definitions exported by this header or compilers using
54  * this header are:
55  *
56  * the macro __va_start(list, name) starting the list iteration
57  * the macro __va_arg(list, type) getting the current arg and iterating
58  * the macro __va_copy(to, from) to bookmark the list iteration
59  * the macro __va_end(list) to end the iteration
60  *
61  * In addition, the following are exported via inclusion of <sys/va_list.h>:
62  *
63  * the identifier __builtin_va_alist for the variable list pseudo parameter
64  * the type __va_alist_type for the variable list pseudo parameter
65  * the type __va_list defining the type of the variable list iterator
66  */
67 
68 /*
69  * This header uses feature macros (e.g. __BUILTIN_VA_ARG_INCR and
70  * __BUILTIN_VA_STRUCT), compiler macros (e.g. __GNUC__), and processor
71  * macros (e.g. __sparc) to determine the protocol appropriate to the
72  * current compilation.  It is intended that the compilation system
73  * define the feature, processor, and compiler macros, not the user of
74  * the system.
75  */
76 
77 /*
78  * Many compilation systems depend upon the use of special functions
79  * built into the the compilation system to handle variable argument
80  * lists.  These built-in symbols may include one or more of the
81  * following:
82  *
83  *      __builtin_va_alist
84  *      __builtin_va_start
85  *      __builtin_va_arg_incr
86  *      __builtin_stdarg_start
87  *      __builtin_va_end
88  *      __builtin_va_arg
89  *      __builtin_va_copy
90  */
91 
92 /*
93  * The following are defined in <sys/va_list.h>:
94  *
95  *      __va_alist_type
96  *      __va_void()
97  *      __va_ptr_base
98  *      ISA definitions via inclusion of <sys/isa_defs.h>
99  *
100  * Inclusion of this header also makes visible the symbols in <sys/va_list.h>.
101  * This header is included in <varargs.h>, <sys/varargs.h> and in <stdarg.h>
102  * via inclusion of <iso/stdarg_iso.h>.
103  */
104 
105 #include <sys/va_list.h>
106 
107 #ifdef	__cplusplus
108 extern "C" {
109 #endif
110 
111 #if defined(__lint)	/* ---------------------------------------- protocol */
112 
113 #define	__va_start(list, name)	((list) = (__va_list)&name)
114 #define	__va_arg(list, type)	((type *)(list))[0]
115 #define	__va_copy(to, from)	__va_void(((to) = (from)))
116 /*ARGSUSED*/
117 static void __va_end(__va_list list) { __va_end(list); }
118 
119 #elif defined(__BUILTIN_VA_STRUCT)	/* ------------------------ protocol */
120 
121 /* ISA __va_list structures defined in <sys/va_list.h> */
122 
123 #if defined(__STDC__)	/* source language is ISO C or C++ */
124 
125 void __builtin_va_start(__va_list, ...);
126 void *__builtin_va_arg_incr(__va_list, ...);
127 
128 #else	/* source language is K&R C */
129 
130 int __builtin_va_start();
131 char *__builtin_va_arg_incr();
132 
133 #endif	/* source language */
134 
135 #define	__va_start(list, name)	__builtin_va_start(list, 0)
136 #define	__va_arg(list, type)	\
137 	((type *)__builtin_va_arg_incr(list, (type *)0))[0]
138 #define	__va_copy(to, from)	__va_void(((to)[0] = (from)[0]))
139 #define	__va_end(list)		__va_void(0)
140 
141 #elif defined(__BUILTIN_VA_ARG_INCR)	/* ------------------------ protocol */
142 
143 #define	__va_start(list, name)	\
144 	__va_void(((list) = (__va_list)&__builtin_va_alist))
145 #define	__va_arg(list, type)	\
146 	((type *)__builtin_va_arg_incr((type *)(list)))[0]
147 #define	__va_copy(to, from)	__va_void(((to) = (from)))
148 #define	__va_end(list)		__va_void(0)
149 
150 #elif defined(__GNUC__)	&& ((__GNUC__ == 2 && __GNUC_MINOR >= 96) || \
151 	(__GNUC__ >= 3))		/* ------------------------ protocol */
152 
153 #define	__va_start(list, name)	__builtin_stdarg_start(list, name)
154 #define	__va_arg(list, type)	__builtin_va_arg(list, type)
155 #define	__va_end(list)		__builtin_va_end(list)
156 #define	__va_copy(to, from)	__builtin_va_copy(to, from)
157 
158 #else					/* ----------------------- protocol */
159 
160 /*
161  * Because we can not predict the compiler protocol for unknown compilers, we
162  * force an error in order to avoid unpredictable behavior. For versions of
163  * gcc 2.95 and earlier, variable argument lists are handled in gcc specific
164  * stdarg.h and varargs.h headers created via the gcc fixincl utility. In
165  * those cases, the gcc headers would override this header.
166  */
167 
168 #error("Unrecognized compiler protocol for variable argument lists")
169 
170 #endif  /* -------------------------------------------------------- protocol */
171 
172 #ifdef	__cplusplus
173 }
174 #endif
175 
176 #endif	/* _SYS_VA_IMPL_H */
177