2002-03-15 Eric Christopher <echristo@redhat.com>
[official-gcc.git] / include / ansidecl.h
blob9a7c5777ff2ece9641045ce4a6b6b90e93b3b3c7
1 /* ANSI and traditional C compatability macros
2 Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001
3 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 /* ANSI and traditional C compatibility macros
22 ANSI C is assumed if __STDC__ is #defined.
24 Macro ANSI C definition Traditional C definition
25 ----- ---- - ---------- ----------- - ----------
26 ANSI_PROTOTYPES 1 not defined
27 PTR `void *' `char *'
28 PTRCONST `void *const' `char *'
29 LONG_DOUBLE `long double' `double'
30 const not defined `'
31 volatile not defined `'
32 signed not defined `'
33 VA_START(ap, var) va_start(ap, var) va_start(ap)
35 Note that it is safe to write "void foo();" indicating a function
36 with no return value, in all K+R compilers we have been able to test.
38 For declaring functions with prototypes, we also provide these:
40 PARAMS ((prototype))
41 -- for functions which take a fixed number of arguments. Use this
42 when declaring the function. When defining the function, write a
43 K+R style argument list. For example:
45 char *strcpy PARAMS ((char *dest, char *source));
46 ...
47 char *
48 strcpy (dest, source)
49 char *dest;
50 char *source;
51 { ... }
54 VPARAMS ((prototype, ...))
55 -- for functions which take a variable number of arguments. Use
56 PARAMS to declare the function, VPARAMS to define it. For example:
58 int printf PARAMS ((const char *format, ...));
59 ...
60 int
61 printf VPARAMS ((const char *format, ...))
63 ...
66 For writing functions which take variable numbers of arguments, we
67 also provide the VA_OPEN, VA_CLOSE, and VA_FIXEDARG macros. These
68 hide the differences between K+R <varargs.h> and C89 <stdarg.h> more
69 thoroughly than the simple VA_START() macro mentioned above.
71 VA_OPEN and VA_CLOSE are used *instead of* va_start and va_end.
72 Immediately after VA_OPEN, put a sequence of VA_FIXEDARG calls
73 corresponding to the list of fixed arguments. Then use va_arg
74 normally to get the variable arguments, or pass your va_list object
75 around. You do not declare the va_list yourself; VA_OPEN does it
76 for you.
78 Here is a complete example:
80 int
81 printf VPARAMS ((const char *format, ...))
83 int result;
85 VA_OPEN (ap, format);
86 VA_FIXEDARG (ap, const char *, format);
88 result = vfprintf (stdout, format, ap);
89 VA_CLOSE (ap);
91 return result;
95 You can declare variables either before or after the VA_OPEN,
96 VA_FIXEDARG sequence. Also, VA_OPEN and VA_CLOSE are the beginning
97 and end of a block. They must appear at the same nesting level,
98 and any variables declared after VA_OPEN go out of scope at
99 VA_CLOSE. Unfortunately, with a K+R compiler, that includes the
100 argument list. You can have multiple instances of VA_OPEN/VA_CLOSE
101 pairs in a single function in case you need to traverse the
102 argument list more than once.
104 For ease of writing code which uses GCC extensions but needs to be
105 portable to other compilers, we provide the GCC_VERSION macro that
106 simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
107 wrappers around __attribute__. Also, __extension__ will be #defined
108 to nothing if it doesn't work. See below.
110 This header also defines a lot of obsolete macros:
111 CONST, VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID,
112 AND, DOTS, NOARGS. Don't use them. */
114 #ifndef _ANSIDECL_H
115 #define _ANSIDECL_H 1
117 /* Every source file includes this file,
118 so they will all get the switch for lint. */
119 /* LINTLIBRARY */
121 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
122 older preprocessors. Thus we can't define something like this:
124 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
125 (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
127 and then test "#if HAVE_GCC_VERSION(2,7)".
129 So instead we use the macro below and test it against specific values. */
131 /* This macro simplifies testing whether we are using gcc, and if it
132 is of a particular minimum version. (Both major & minor numbers are
133 significant.) This macro will evaluate to 0 if we are not using
134 gcc at all. */
135 #ifndef GCC_VERSION
136 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
137 #endif /* GCC_VERSION */
139 #if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32)
140 /* All known AIX compilers implement these things (but don't always
141 define __STDC__). The RISC/OS MIPS compiler defines these things
142 in SVR4 mode, but does not define __STDC__. */
144 #define ANSI_PROTOTYPES 1
145 #define PTR void *
146 #define PTRCONST void *const
147 #define LONG_DOUBLE long double
149 #define PARAMS(ARGS) ARGS
150 #define VPARAMS(ARGS) ARGS
151 #define VA_START(VA_LIST, VAR) va_start(VA_LIST, VAR)
153 /* variadic function helper macros */
154 /* "struct Qdmy" swallows the semicolon after VA_OPEN/VA_FIXEDARG's
155 use without inhibiting further decls and without declaring an
156 actual variable. */
157 #define VA_OPEN(AP, VAR) { va_list AP; va_start(AP, VAR); { struct Qdmy
158 #define VA_CLOSE(AP) } va_end(AP); }
159 #define VA_FIXEDARG(AP, T, N) struct Qdmy
161 #undef const
162 #undef volatile
163 #undef signed
165 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
166 it too, but it's not in C89. */
167 #undef inline
168 #if __STDC_VERSION__ > 199901L
169 /* it's a keyword */
170 #else
171 # if GCC_VERSION >= 2007
172 # define inline __inline__ /* __inline__ prevents -pedantic warnings */
173 # else
174 # define inline /* nothing */
175 # endif
176 #endif
178 /* These are obsolete. Do not use. */
179 #ifndef IN_GCC
180 #define CONST const
181 #define VOLATILE volatile
182 #define SIGNED signed
184 #define PROTO(type, name, arglist) type name arglist
185 #define EXFUN(name, proto) name proto
186 #define DEFUN(name, arglist, args) name(args)
187 #define DEFUN_VOID(name) name(void)
188 #define AND ,
189 #define DOTS , ...
190 #define NOARGS void
191 #endif /* ! IN_GCC */
193 #else /* Not ANSI C. */
195 #undef ANSI_PROTOTYPES
196 #define PTR char *
197 #define PTRCONST PTR
198 #define LONG_DOUBLE double
200 #define PARAMS(args) ()
201 #define VPARAMS(args) (va_alist) va_dcl
202 #define VA_START(va_list, var) va_start(va_list)
204 #define VA_OPEN(AP, VAR) { va_list AP; va_start(AP); { struct Qdmy
205 #define VA_CLOSE(AP) } va_end(AP); }
206 #define VA_FIXEDARG(AP, TYPE, NAME) TYPE NAME = va_arg(AP, TYPE)
208 /* some systems define these in header files for non-ansi mode */
209 #undef const
210 #undef volatile
211 #undef signed
212 #undef inline
213 #define const
214 #define volatile
215 #define signed
216 #define inline
218 #ifndef IN_GCC
219 #define CONST
220 #define VOLATILE
221 #define SIGNED
223 #define PROTO(type, name, arglist) type name ()
224 #define EXFUN(name, proto) name()
225 #define DEFUN(name, arglist, args) name arglist args;
226 #define DEFUN_VOID(name) name()
227 #define AND ;
228 #define DOTS
229 #define NOARGS
230 #endif /* ! IN_GCC */
232 #endif /* ANSI C. */
234 /* Define macros for some gcc attributes. This permits us to use the
235 macros freely, and know that they will come into play for the
236 version of gcc in which they are supported. */
238 #if (GCC_VERSION < 2007)
239 # define __attribute__(x)
240 #endif
242 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
243 #ifndef ATTRIBUTE_MALLOC
244 # if (GCC_VERSION >= 2096)
245 # define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
246 # else
247 # define ATTRIBUTE_MALLOC
248 # endif /* GNUC >= 2.96 */
249 #endif /* ATTRIBUTE_MALLOC */
251 /* Attributes on labels were valid as of gcc 2.93. */
252 #ifndef ATTRIBUTE_UNUSED_LABEL
253 # if (GCC_VERSION >= 2093)
254 # define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
255 # else
256 # define ATTRIBUTE_UNUSED_LABEL
257 # endif /* GNUC >= 2.93 */
258 #endif /* ATTRIBUTE_UNUSED_LABEL */
260 #ifndef ATTRIBUTE_UNUSED
261 #define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
262 #endif /* ATTRIBUTE_UNUSED */
264 #ifndef ATTRIBUTE_NORETURN
265 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
266 #endif /* ATTRIBUTE_NORETURN */
268 #ifndef ATTRIBUTE_PRINTF
269 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
270 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
271 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
272 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
273 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
274 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
275 #endif /* ATTRIBUTE_PRINTF */
277 /* We use __extension__ in some places to suppress -pedantic warnings
278 about GCC extensions. This feature didn't work properly before
279 gcc 2.8. */
280 #if GCC_VERSION < 2008
281 #define __extension__
282 #endif
284 /* Bootstrap support: Adjust certain macros defined by Autoconf,
285 which are only valid for the stage1 compiler. If we detect
286 a modern version of GCC, we are probably in stage2 or beyond,
287 so unconditionally reset the values. Note that const, inline,
288 etc. have been dealt with above. */
289 #if (GCC_VERSION >= 2007)
290 # ifndef HAVE_LONG_DOUBLE
291 # define HAVE_LONG_DOUBLE 1
292 # endif
293 #endif /* GCC >= 2.7 */
295 #endif /* ansidecl.h */