1 /* ANSI and traditional C compatability macros
2    Copyright (C) 1991-2018 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9 
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 GNU General Public License for more details.
14 
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
18 
19 /* ANSI and traditional C compatibility macros
20 
21    ANSI C is assumed if __STDC__ is #defined.
22 
23    Macro		ANSI C definition	Traditional C definition
24    -----		---- - ----------	----------- - ----------
25    PTR			`void *'		`char *'
26    const		not defined		`'
27    volatile		not defined		`'
28    signed		not defined		`'
29 
30    For ease of writing code which uses GCC extensions but needs to be
31    portable to other compilers, we provide the GCC_VERSION macro that
32    simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
33    wrappers around __attribute__.  Also, __extension__ will be #defined
34    to nothing if it doesn't work.  See below.  */
35 
36 #ifndef	_ANSIDECL_H
37 #define _ANSIDECL_H	1
38 
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
42 
43 /* Every source file includes this file,
44    so they will all get the switch for lint.  */
45 /* LINTLIBRARY */
46 
47 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
48    older preprocessors.  Thus we can't define something like this:
49 
50 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
51   (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
52 
53 and then test "#if HAVE_GCC_VERSION(2,7)".
54 
55 So instead we use the macro below and test it against specific values.  */
56 
57 /* This macro simplifies testing whether we are using gcc, and if it
58    is of a particular minimum version. (Both major & minor numbers are
59    significant.)  This macro will evaluate to 0 if we are not using
60    gcc at all.  */
61 #ifndef GCC_VERSION
62 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
63 #endif /* GCC_VERSION */
64 
65 #if defined (__STDC__) || defined(__cplusplus) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32)
66 /* All known AIX compilers implement these things (but don't always
67    define __STDC__).  The RISC/OS MIPS compiler defines these things
68    in SVR4 mode, but does not define __STDC__.  */
69 /* eraxxon@alumni.rice.edu: The Compaq C++ compiler, unlike many other
70    C++ compilers, does not define __STDC__, though it acts as if this
71    was so. (Verified versions: 5.7, 6.2, 6.3, 6.5) */
72 
73 #define PTR		void *
74 
75 #undef const
76 #undef volatile
77 #undef signed
78 
79 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
80    it too, but it's not in C89.  */
81 #undef inline
82 #if __STDC_VERSION__ >= 199901L || defined(__cplusplus) || (defined(__SUNPRO_C) && defined(__C99FEATURES__))
83 /* it's a keyword */
84 #else
85 # if GCC_VERSION >= 2007
86 #  define inline __inline__   /* __inline__ prevents -pedantic warnings */
87 # else
88 #  define inline  /* nothing */
89 # endif
90 #endif
91 
92 #else	/* Not ANSI C.  */
93 
94 #define PTR		char *
95 
96 /* some systems define these in header files for non-ansi mode */
97 #undef const
98 #undef volatile
99 #undef signed
100 #undef inline
101 #define const
102 #define volatile
103 #define signed
104 #define inline
105 
106 #endif	/* ANSI C.  */
107 
108 /* Define macros for some gcc attributes.  This permits us to use the
109    macros freely, and know that they will come into play for the
110    version of gcc in which they are supported.  */
111 
112 #if (GCC_VERSION < 2007)
113 # define __attribute__(x)
114 #endif
115 
116 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
117 #ifndef ATTRIBUTE_MALLOC
118 # if (GCC_VERSION >= 2096)
119 #  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
120 # else
121 #  define ATTRIBUTE_MALLOC
122 # endif /* GNUC >= 2.96 */
123 #endif /* ATTRIBUTE_MALLOC */
124 
125 /* Attributes on labels were valid as of gcc 2.93 and g++ 4.5.  For
126    g++ an attribute on a label must be followed by a semicolon.  */
127 #ifndef ATTRIBUTE_UNUSED_LABEL
128 # ifndef __cplusplus
129 #  if GCC_VERSION >= 2093
130 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
131 #  else
132 #   define ATTRIBUTE_UNUSED_LABEL
133 #  endif
134 # else
135 #  if GCC_VERSION >= 4005
136 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED ;
137 #  else
138 #   define ATTRIBUTE_UNUSED_LABEL
139 #  endif
140 # endif
141 #endif
142 
143 /* Similarly to ARG_UNUSED below.  Prior to GCC 3.4, the C++ frontend
144    couldn't parse attributes placed after the identifier name, and now
145    the entire compiler is built with C++.  */
146 #ifndef ATTRIBUTE_UNUSED
147 #if GCC_VERSION >= 3004
148 #  define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
149 #else
150 #define ATTRIBUTE_UNUSED
151 #endif
152 #endif /* ATTRIBUTE_UNUSED */
153 
154 /* Before GCC 3.4, the C++ frontend couldn't parse attributes placed after the
155    identifier name.  */
156 #if ! defined(__cplusplus) || (GCC_VERSION >= 3004)
157 # define ARG_UNUSED(NAME) NAME ATTRIBUTE_UNUSED
158 #else /* !__cplusplus || GNUC >= 3.4 */
159 # define ARG_UNUSED(NAME) NAME
160 #endif /* !__cplusplus || GNUC >= 3.4 */
161 
162 #ifndef ATTRIBUTE_NORETURN
163 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
164 #endif /* ATTRIBUTE_NORETURN */
165 
166 /* Attribute `nonnull' was valid as of gcc 3.3.  */
167 #ifndef ATTRIBUTE_NONNULL
168 # if (GCC_VERSION >= 3003)
169 #  define ATTRIBUTE_NONNULL(m) __attribute__ ((__nonnull__ (m)))
170 # else
171 #  define ATTRIBUTE_NONNULL(m)
172 # endif /* GNUC >= 3.3 */
173 #endif /* ATTRIBUTE_NONNULL */
174 
175 /* Attribute `returns_nonnull' was valid as of gcc 4.9.  */
176 #ifndef ATTRIBUTE_RETURNS_NONNULL
177 # if (GCC_VERSION >= 4009)
178 #  define ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
179 # else
180 #  define ATTRIBUTE_RETURNS_NONNULL
181 # endif /* GNUC >= 4.9 */
182 #endif /* ATTRIBUTE_RETURNS_NONNULL */
183 
184 /* Attribute `pure' was valid as of gcc 3.0.  */
185 #ifndef ATTRIBUTE_PURE
186 # if (GCC_VERSION >= 3000)
187 #  define ATTRIBUTE_PURE __attribute__ ((__pure__))
188 # else
189 #  define ATTRIBUTE_PURE
190 # endif /* GNUC >= 3.0 */
191 #endif /* ATTRIBUTE_PURE */
192 
193 /* Use ATTRIBUTE_PRINTF when the format specifier must not be NULL.
194    This was the case for the `printf' format attribute by itself
195    before GCC 3.3, but as of 3.3 we need to add the `nonnull'
196    attribute to retain this behavior.  */
197 #ifndef ATTRIBUTE_PRINTF
198 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n))) ATTRIBUTE_NONNULL(m)
199 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
200 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
201 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
202 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
203 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
204 #endif /* ATTRIBUTE_PRINTF */
205 
206 /* Use ATTRIBUTE_FPTR_PRINTF when the format attribute is to be set on
207    a function pointer.  Format attributes were allowed on function
208    pointers as of gcc 3.1.  */
209 #ifndef ATTRIBUTE_FPTR_PRINTF
210 # if (GCC_VERSION >= 3001)
211 #  define ATTRIBUTE_FPTR_PRINTF(m, n) ATTRIBUTE_PRINTF(m, n)
212 # else
213 #  define ATTRIBUTE_FPTR_PRINTF(m, n)
214 # endif /* GNUC >= 3.1 */
215 # define ATTRIBUTE_FPTR_PRINTF_1 ATTRIBUTE_FPTR_PRINTF(1, 2)
216 # define ATTRIBUTE_FPTR_PRINTF_2 ATTRIBUTE_FPTR_PRINTF(2, 3)
217 # define ATTRIBUTE_FPTR_PRINTF_3 ATTRIBUTE_FPTR_PRINTF(3, 4)
218 # define ATTRIBUTE_FPTR_PRINTF_4 ATTRIBUTE_FPTR_PRINTF(4, 5)
219 # define ATTRIBUTE_FPTR_PRINTF_5 ATTRIBUTE_FPTR_PRINTF(5, 6)
220 #endif /* ATTRIBUTE_FPTR_PRINTF */
221 
222 /* Use ATTRIBUTE_NULL_PRINTF when the format specifier may be NULL.  A
223    NULL format specifier was allowed as of gcc 3.3.  */
224 #ifndef ATTRIBUTE_NULL_PRINTF
225 # if (GCC_VERSION >= 3003)
226 #  define ATTRIBUTE_NULL_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
227 # else
228 #  define ATTRIBUTE_NULL_PRINTF(m, n)
229 # endif /* GNUC >= 3.3 */
230 # define ATTRIBUTE_NULL_PRINTF_1 ATTRIBUTE_NULL_PRINTF(1, 2)
231 # define ATTRIBUTE_NULL_PRINTF_2 ATTRIBUTE_NULL_PRINTF(2, 3)
232 # define ATTRIBUTE_NULL_PRINTF_3 ATTRIBUTE_NULL_PRINTF(3, 4)
233 # define ATTRIBUTE_NULL_PRINTF_4 ATTRIBUTE_NULL_PRINTF(4, 5)
234 # define ATTRIBUTE_NULL_PRINTF_5 ATTRIBUTE_NULL_PRINTF(5, 6)
235 #endif /* ATTRIBUTE_NULL_PRINTF */
236 
237 /* Attribute `sentinel' was valid as of gcc 3.5.  */
238 #ifndef ATTRIBUTE_SENTINEL
239 # if (GCC_VERSION >= 3005)
240 #  define ATTRIBUTE_SENTINEL __attribute__ ((__sentinel__))
241 # else
242 #  define ATTRIBUTE_SENTINEL
243 # endif /* GNUC >= 3.5 */
244 #endif /* ATTRIBUTE_SENTINEL */
245 
246 
247 #ifndef ATTRIBUTE_ALIGNED_ALIGNOF
248 # if (GCC_VERSION >= 3000)
249 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m) __attribute__ ((__aligned__ (__alignof__ (m))))
250 # else
251 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m)
252 # endif /* GNUC >= 3.0 */
253 #endif /* ATTRIBUTE_ALIGNED_ALIGNOF */
254 
255 /* Useful for structures whose layout must match some binary specification
256    regardless of the alignment and padding qualities of the compiler.  */
257 #ifndef ATTRIBUTE_PACKED
258 # define ATTRIBUTE_PACKED __attribute__ ((packed))
259 #endif
260 
261 /* Attribute `hot' and `cold' was valid as of gcc 4.3.  */
262 #ifndef ATTRIBUTE_COLD
263 # if (GCC_VERSION >= 4003)
264 #  define ATTRIBUTE_COLD __attribute__ ((__cold__))
265 # else
266 #  define ATTRIBUTE_COLD
267 # endif /* GNUC >= 4.3 */
268 #endif /* ATTRIBUTE_COLD */
269 #ifndef ATTRIBUTE_HOT
270 # if (GCC_VERSION >= 4003)
271 #  define ATTRIBUTE_HOT __attribute__ ((__hot__))
272 # else
273 #  define ATTRIBUTE_HOT
274 # endif /* GNUC >= 4.3 */
275 #endif /* ATTRIBUTE_HOT */
276 
277 /* Attribute 'no_sanitize_undefined' was valid as of gcc 4.9.  */
278 #ifndef ATTRIBUTE_NO_SANITIZE_UNDEFINED
279 # if (GCC_VERSION >= 4009)
280 #  define ATTRIBUTE_NO_SANITIZE_UNDEFINED __attribute__ ((no_sanitize_undefined))
281 # else
282 #  define ATTRIBUTE_NO_SANITIZE_UNDEFINED
283 # endif /* GNUC >= 4.9 */
284 #endif /* ATTRIBUTE_NO_SANITIZE_UNDEFINED */
285 
286 /* We use __extension__ in some places to suppress -pedantic warnings
287    about GCC extensions.  This feature didn't work properly before
288    gcc 2.8.  */
289 #if GCC_VERSION < 2008
290 #define __extension__
291 #endif
292 
293 /* This is used to declare a const variable which should be visible
294    outside of the current compilation unit.  Use it as
295      EXPORTED_CONST int i = 1;
296    This is because the semantics of const are different in C and C++.
297    "extern const" is permitted in C but it looks strange, and gcc
298    warns about it when -Wc++-compat is not used.  */
299 #ifdef __cplusplus
300 #define EXPORTED_CONST extern const
301 #else
302 #define EXPORTED_CONST const
303 #endif
304 
305 /* Be conservative and only use enum bitfields with C++ or GCC.
306    FIXME: provide a complete autoconf test for buggy enum bitfields.  */
307 
308 #ifdef __cplusplus
309 #define ENUM_BITFIELD(TYPE) enum TYPE
310 #elif (GCC_VERSION > 2000)
311 #define ENUM_BITFIELD(TYPE) __extension__ enum TYPE
312 #else
313 #define ENUM_BITFIELD(TYPE) unsigned int
314 #endif
315 
316 #if __cpp_constexpr >= 200704
317 #define CONSTEXPR constexpr
318 #else
319 #define CONSTEXPR
320 #endif
321 
322 /* C++11 adds the ability to add "override" after an implementation of a
323    virtual function in a subclass, to:
324      (A) document that this is an override of a virtual function
325      (B) allow the compiler to issue a warning if it isn't (e.g. a mismatch
326          of the type signature).
327 
328    Similarly, it allows us to add a "final" to indicate that no subclass
329    may subsequently override the vfunc.
330 
331    Provide OVERRIDE and FINAL as macros, allowing us to get these benefits
332    when compiling with C++11 support, but without requiring C++11.
333 
334    For gcc, use "-std=c++11" to enable C++11 support; gcc 6 onwards enables
335    this by default (actually GNU++14).  */
336 
337 #if defined __cplusplus
338 # if __cplusplus >= 201103
339    /* C++11 claims to be available: use it.  Final/override were only
340       implemented in 4.7, though.  */
341 #  if GCC_VERSION < 4007
342 #   define OVERRIDE
343 #   define FINAL
344 #  else
345 #   define OVERRIDE override
346 #   define FINAL final
347 #  endif
348 # elif GCC_VERSION >= 4007
349    /* G++ 4.7 supports __final in C++98.  */
350 #  define OVERRIDE
351 #  define FINAL __final
352 # else
353    /* No C++11 support; leave the macros empty.  */
354 #  define OVERRIDE
355 #  define FINAL
356 # endif
357 #else
358   /* No C++11 support; leave the macros empty.  */
359 # define OVERRIDE
360 # define FINAL
361 #endif
362 
363 /* A macro to disable the copy constructor and assignment operator.
364    When building with C++11 and above, the methods are explicitly
365    deleted, causing a compile-time error if something tries to copy.
366    For C++03, this just declares the methods, causing a link-time
367    error if the methods end up called (assuming you don't
368    define them).  For C++03, for best results, place the macro
369    under the private: access specifier, like this,
370 
371    class name_lookup
372    {
373      private:
374        DISABLE_COPY_AND_ASSIGN (name_lookup);
375    };
376 
377    so that most attempts at copy are caught at compile-time.  */
378 
379 #if __cplusplus >= 201103
380 #define DISABLE_COPY_AND_ASSIGN(TYPE)		\
381   TYPE (const TYPE&) = delete;			\
382   void operator= (const TYPE &) = delete
383   #else
384 #define DISABLE_COPY_AND_ASSIGN(TYPE)		\
385   TYPE (const TYPE&);				\
386   void operator= (const TYPE &)
387 #endif /* __cplusplus >= 201103 */
388 
389 #ifdef __cplusplus
390 }
391 #endif
392 
393 #endif	/* ansidecl.h	*/
394