File: /usr/include/sys/cdefs.h
1 /* Copyright (C) 1992,93,94,95,96,97,98,99, 2000 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
13
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
18
19 #ifndef _SYS_CDEFS_H
20 #define _SYS_CDEFS_H 1
21
22 /* We are almost always included from features.h. */
23 #ifndef _FEATURES_H
24 # include <features.h>
25 #endif
26
27 /* The GNU libc does not support any K&R compilers or the traditional mode
28 of ISO C compilers anymore. Check for some of the combinations not
29 anymore supported. */
30 #if defined __GNUC__ && !defined __STDC__
31 # error "You need a ISO C conforming compiler to use the glibc headers"
32 #endif
33
34 /* Some user header file might have defined this before. */
35 #undef __P
36 #undef __PMT
37
38 #ifdef __GNUC__
39
40 /* GCC can always grok prototypes. For C++ programs we add throw()
41 to help it optimize the function calls. But this works only with
42 gcc 2.8.x and egcs. */
43 # if defined __cplusplus && __GNUC_PREREQ (2,8)
44 # define __THROW throw ()
45 # else
46 # define __THROW
47 # endif
48 # define __P(args) args __THROW
49 /* This macro will be used for functions which might take C++ callback
50 functions. */
51 # define __PMT(args) args
52
53 #else /* Not GCC. */
54
55 # define __inline /* No inline functions. */
56
57 # define __THROW
58 # define __P(args) args
59 # define __PMT(args) args
60
61 # define __const const
62 # define __signed signed
63 # define __volatile volatile
64
65 #endif /* GCC. */
66
67 /* For these things, GCC behaves the ANSI way normally,
68 and the non-ANSI way under -traditional. */
69
70 #define __CONCAT(x,y) x ## y
71 #define __STRING(x) #x
72
73 /* This is not a typedef so `const __ptr_t' does the right thing. */
74 #define __ptr_t void *
75 #define __long_double_t long double
76
77
78 /* C++ needs to know that types and declarations are C, not C++. */
79 #ifdef __cplusplus
80 # define __BEGIN_DECLS extern "C" {
81 # define __END_DECLS }
82 #else
83 # define __BEGIN_DECLS
84 # define __END_DECLS
85 #endif
86
87
88 /* Support for bounded pointers. */
89 #ifndef __BOUNDED_POINTERS__
90 # define __bounded /* nothing */
91 # define __unbounded /* nothing */
92 # define __ptrvalue /* nothing */
93 #endif
94
95
96 /* Support for flexible arrays. */
97 #if __GNUC_PREREQ (2,97)
98 /* GCC 2.97 supports C99 flexible array members. */
99 # define __flexarr []
100 #else
101 # ifdef __GNUC__
102 # define __flexarr [0]
103 # else
104 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
105 # define __flexarr []
106 # else
107 /* Some other non-C99 compiler. Approximate with [1]. */
108 # define __flexarr [1]
109 # endif
110 # endif
111 #endif
112
113
114 /* __asm__ ("xyz") is used throughout the headers to rename functions
115 at the assembly language level. This is wrapped by the __REDIRECT
116 macro, in order to support compilers that can do this some other
117 way. When compilers don't support asm-names at all, we have to do
118 preprocessor tricks instead (which don't have exactly the right
119 semantics, but it's the best we can do).
120
121 Example:
122 int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
123
124 #if defined __GNUC__ && __GNUC__ >= 2
125
126 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
127 # define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
128 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
129
130 /*
131 #elif __SOME_OTHER_COMPILER__
132
133 # define __REDIRECT(name, proto, alias) name proto; \
134 _Pragma("let " #name " = " #alias)
135 */
136 #endif
137
138 /* GCC has various useful declarations that can be made with the
139 `__attribute__' syntax. All of the ways we use this do fine if
140 they are omitted for compilers that don't understand it. */
141 #if !defined __GNUC__ || __GNUC__ < 2
142 # define __attribute__(xyz) /* Ignore */
143 #endif
144
145 /* At some point during the gcc 2.96 development the `malloc' attribute
146 for functions was introduced. We don't want to use it unconditionally
147 (although this would be possible) since it generates warnings. */
148 #if __GNUC_PREREQ (2,96)
149 # define __attribute_malloc__ __attribute__ ((__malloc__))
150 #else
151 # define __attribute_malloc__ /* Ignore */
152 #endif
153
154 /* At some point during the gcc 2.96 development the `pure' attribute
155 for functions was introduced. We don't want to use it unconditionally
156 (although this would be possible) since it generates warnings. */
157 #if __GNUC_PREREQ (2,96)
158 # define __attribute_pure__ __attribute__ ((__pure__))
159 #else
160 # define __attribute_pure__ /* Ignore */
161 #endif
162
163 /* At some point during the gcc 2.8 development the `format_arg' attribute
164 for functions was introduced. We don't want to use it unconditionally
165 (although this would be possible) since it generates warnings. */
166 #if __GNUC_PREREQ (2,8)
167 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
168 #else
169 # define __attribute_format_arg__(x) /* Ignore */
170 #endif
171
172 /* At some point during the gcc 2.97 development the `strfmon' format
173 attribute for functions was introduced. We don't want to use it
174 unconditionally (although this would be possible) since it
175 generates warnings. */
176 #if __GNUC_PREREQ (2,97)
177 # define __attribute_format_strfmon__(a,b) \
178 __attribute__ ((__format__ (__strfmon__, a, b)))
179 #else
180 # define __attribute_format_strfmon__(a,b) /* Ignore */
181 #endif
182
183 /* It is possible to compile containing GCC extensions even if GCC is
184 run in pedantic mode if the uses are carefully marked using the
185 `__extension__' keyword. But this is not generally available before
186 version 2.8. */
187 #if !__GNUC_PREREQ (2,8)
188 # define __extension__ /* Ignore */
189 #endif
190
191 /* __restrict is known in EGCS 1.2 and above. */
192 #if !__GNUC_PREREQ (2,92)
193 # define __restrict /* Ignore */
194 #endif
195
196 /* ISO C99 also allows to declare arrays as non-overlapping. The syntax is
197 array_name[restrict]
198 But gcc so far does not support this syntax. We define a separate macro
199 for this which can be enabled if the underlying compiler supports it. */
200 #define __restrict_arr
201
202 #endif /* sys/cdefs.h */
203