xref: /illumos-gate/usr/src/uts/common/sys/feature_tests.h (revision 9498083eeaed1aacdde41369b7fa6f3b84870791)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2013 Garrett D'Amore <garrett@damore.org>
24  *
25  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 #ifndef _SYS_FEATURE_TESTS_H
30 #define	_SYS_FEATURE_TESTS_H
31 
32 #include <sys/ccompile.h>
33 #include <sys/isa_defs.h>
34 
35 #ifdef	__cplusplus
36 extern "C" {
37 #endif
38 
39 /*
40  * Values of _POSIX_C_SOURCE
41  *
42  *		undefined   not a POSIX compilation
43  *		1	    POSIX.1-1990 compilation
44  *		2	    POSIX.2-1992 compilation
45  *		199309L	    POSIX.1b-1993 compilation (Real Time)
46  *		199506L	    POSIX.1c-1995 compilation (POSIX Threads)
47  *		200112L	    POSIX.1-2001 compilation (Austin Group Revision)
48  *		200809L     POSIX.1-2008 compilation
49  */
50 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE)
51 #define	_POSIX_C_SOURCE 1
52 #endif
53 
54 /*
55  * The feature test macros __XOPEN_OR_POSIX, _STRICT_STDC, _STRICT_SYMBOLS,
56  * and _STDC_C99 are Sun implementation specific macros created in order to
57  * compress common standards specified feature test macros for easier reading.
58  * These macros should not be used by the application developer as
59  * unexpected results may occur. Instead, the user should reference
60  * standards(5) for correct usage of the standards feature test macros.
61  *
62  * __XOPEN_OR_POSIX     Used in cases where a symbol is defined by both
63  *                      X/Open or POSIX or in the negative, when neither
64  *                      X/Open or POSIX defines a symbol.
65  *
66  * _STRICT_STDC         __STDC__ is specified by the C Standards and defined
67  *                      by the compiler. For Sun compilers the value of
68  *                      __STDC__ is either 1, 0, or not defined based on the
69  *                      compilation mode (see cc(1)). When the value of
70  *                      __STDC__ is 1 and in the absence of any other feature
71  *                      test macros, the namespace available to the application
72  *                      is limited to only those symbols defined by the C
73  *                      Standard. _STRICT_STDC provides a more readable means
74  *                      of identifying symbols defined by the standard, or in
75  *                      the negative, symbols that are extensions to the C
76  *                      Standard. See additional comments for GNU C differences.
77  *
78  * _STDC_C99            __STDC_VERSION__ is specified by the C standards and
79  *                      defined by the compiler and indicates the version of
80  *                      the C standard. A value of 199901L indicates a
81  *                      compiler that complies with ISO/IEC 9899:1999, other-
82  *                      wise known as the C99 standard.
83  *
84  * _STRICT_SYMBOLS	Used in cases where symbol visibility is restricted
85  *                      by the standards, and the user has not explicitly
86  *                      relaxed the strictness via __EXTENSIONS__.
87  */
88 
89 #if defined(_XOPEN_SOURCE) || defined(_POSIX_C_SOURCE)
90 #define	__XOPEN_OR_POSIX
91 #endif
92 
93 /*
94  * ISO/IEC 9899:1990 and it's revision, ISO/IEC 9899:1999 specify the
95  * following predefined macro name:
96  *
97  * __STDC__	The integer constant 1, intended to indicate a conforming
98  *		implementation.
99  *
100  * Furthermore, a strictly conforming program shall use only those features
101  * of the language and library specified in these standards. A conforming
102  * implementation shall accept any strictly conforming program.
103  *
104  * Based on these requirements, Sun's C compiler defines __STDC__ to 1 for
105  * strictly conforming environments and __STDC__ to 0 for environments that
106  * use ANSI C semantics but allow extensions to the C standard. For non-ANSI
107  * C semantics, Sun's C compiler does not define __STDC__.
108  *
109  * The GNU C project interpretation is that __STDC__ should always be defined
110  * to 1 for compilation modes that accept ANSI C syntax regardless of whether
111  * or not extensions to the C standard are used. Violations of conforming
112  * behavior are conditionally flagged as warnings via the use of the
113  * -pedantic option. In addition to defining __STDC__ to 1, the GNU C
114  * compiler also defines __STRICT_ANSI__ as a means of specifying strictly
115  * conforming environments using the -ansi or -std=<standard> options.
116  *
117  * In the absence of any other compiler options, Sun and GNU set the value
118  * of __STDC__ as follows when using the following options:
119  *
120  *				Value of __STDC__  __STRICT_ANSI__
121  *
122  * cc -Xa (default)			0	      undefined
123  * cc -Xt (transitional)		0             undefined
124  * cc -Xc (strictly conforming)		1	      undefined
125  * cc -Xs (K&R C)		    undefined	      undefined
126  *
127  * gcc (default)			1	      undefined
128  * gcc -ansi, -std={c89, c99,...)  	1              defined
129  * gcc -traditional (K&R)	    undefined	      undefined
130  *
131  * The default compilation modes for Sun C compilers versus GNU C compilers
132  * results in a differing value for __STDC__ which results in a more
133  * restricted namespace when using Sun compilers. To allow both GNU and Sun
134  * interpretations to peacefully co-exist, we use the following Sun
135  * implementation _STRICT_STDC_ macro:
136  */
137 
138 #if (__STDC__ - 0 == 1 && !defined(__GNUC__)) || \
139 	(defined(__GNUC__) && defined(__STRICT_ANSI__))
140 #define	_STRICT_STDC
141 #else
142 #undef	_STRICT_STDC
143 #endif
144 
145 /*
146  * Compiler complies with ISO/IEC 9899:1999
147  */
148 
149 #if __STDC_VERSION__ - 0 >= 199901L
150 #define	_STDC_C99
151 #endif
152 
153 /*
154  * Use strict symbol visibility.
155  */
156 #if (defined(_STRICT_STDC) || defined(__XOPEN_OR_POSIX)) && \
157 	!defined(__EXTENSIONS__)
158 #define	_STRICT_SYMBOLS
159 #endif
160 
161 /*
162  * Large file interfaces:
163  *
164  *	_LARGEFILE_SOURCE
165  *		1		large file-related additions to POSIX
166  *				interfaces requested (fseeko, etc.)
167  *	_LARGEFILE64_SOURCE
168  *		1		transitional large-file-related interfaces
169  *				requested (seek64, stat64, etc.)
170  *
171  * The corresponding announcement macros are respectively:
172  *	_LFS_LARGEFILE
173  *	_LFS64_LARGEFILE
174  * (These are set in <unistd.h>.)
175  *
176  * Requesting _LARGEFILE64_SOURCE implies requesting _LARGEFILE_SOURCE as
177  * well.
178  *
179  * The large file interfaces are made visible regardless of the initial values
180  * of the feature test macros under certain circumstances:
181  *    -	If no explicit standards-conforming environment is requested (neither
182  *	of _POSIX_SOURCE nor _XOPEN_SOURCE is defined and the value of
183  *	__STDC__ does not imply standards conformance).
184  *    -	Extended system interfaces are explicitly requested (__EXTENSIONS__
185  * 	is defined).
186  *    -	Access to in-kernel interfaces is requested (_KERNEL or _KMEMUSER is
187  *	defined).  (Note that this dependency is an artifact of the current
188  *	kernel implementation and may change in future releases.)
189  */
190 #if	(!defined(_STRICT_STDC) && !defined(__XOPEN_OR_POSIX)) || \
191 		defined(_KERNEL) || defined(_KMEMUSER) || \
192 		defined(__EXTENSIONS__)
193 #undef	_LARGEFILE64_SOURCE
194 #define	_LARGEFILE64_SOURCE	1
195 #endif
196 #if	_LARGEFILE64_SOURCE - 0 == 1
197 #undef	_LARGEFILE_SOURCE
198 #define	_LARGEFILE_SOURCE	1
199 #endif
200 
201 /*
202  * Large file compilation environment control:
203  *
204  * The setting of _FILE_OFFSET_BITS controls the size of various file-related
205  * types and governs the mapping between file-related source function symbol
206  * names and the corresponding binary entry points.
207  *
208  * In the 32-bit environment, the default value is 32; if not set, set it to
209  * the default here, to simplify tests in other headers.
210  *
211  * In the 64-bit compilation environment, the only value allowed is 64.
212  */
213 #if defined(_LP64)
214 #ifndef _FILE_OFFSET_BITS
215 #define	_FILE_OFFSET_BITS	64
216 #endif
217 #if	_FILE_OFFSET_BITS - 0 != 64
218 #error	"invalid _FILE_OFFSET_BITS value specified"
219 #endif
220 #else	/* _LP64 */
221 #ifndef	_FILE_OFFSET_BITS
222 #define	_FILE_OFFSET_BITS	32
223 #endif
224 #if	_FILE_OFFSET_BITS - 0 != 32 && _FILE_OFFSET_BITS - 0 != 64
225 #error	"invalid _FILE_OFFSET_BITS value specified"
226 #endif
227 #endif	/* _LP64 */
228 
229 /*
230  * Use of _XOPEN_SOURCE
231  *
232  * The following X/Open specifications are supported:
233  *
234  * X/Open Portability Guide, Issue 3 (XPG3)
235  * X/Open CAE Specification, Issue 4 (XPG4)
236  * X/Open CAE Specification, Issue 4, Version 2 (XPG4v2)
237  * X/Open CAE Specification, Issue 5 (XPG5)
238  * Open Group Technical Standard, Issue 6 (XPG6), also referred to as
239  *    IEEE Std. 1003.1-2001 and ISO/IEC 9945:2002.
240  * Open Group Technical Standard, Issue 7 (XPG7), also referred to as
241  *    IEEE Std. 1003.1-2008 and ISO/IEC 9945:2009.
242  *
243  * XPG4v2 is also referred to as UNIX 95 (SUS or SUSv1).
244  * XPG5 is also referred to as UNIX 98 or the Single Unix Specification,
245  *     Version 2 (SUSv2)
246  * XPG6 is the result of a merge of the X/Open and POSIX specifications
247  *     and as such is also referred to as IEEE Std. 1003.1-2001 in
248  *     addition to UNIX 03 and SUSv3.
249  * XPG7 is also referred to as UNIX 08 and SUSv4.
250  *
251  * When writing a conforming X/Open application, as per the specification
252  * requirements, the appropriate feature test macros must be defined at
253  * compile time. These are as follows. For more info, see standards(5).
254  *
255  * Feature Test Macro				     Specification
256  * ------------------------------------------------  -------------
257  * _XOPEN_SOURCE                                         XPG3
258  * _XOPEN_SOURCE && _XOPEN_VERSION = 4                   XPG4
259  * _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED = 1           XPG4v2
260  * _XOPEN_SOURCE = 500                                   XPG5
261  * _XOPEN_SOURCE = 600  (or POSIX_C_SOURCE=200112L)      XPG6
262  * _XOPEN_SOURCE = 700  (or POSIX_C_SOURCE=200809L)      XPG7
263  *
264  * In order to simplify the guards within the headers, the following
265  * implementation private test macros have been created. Applications
266  * must NOT use these private test macros as unexpected results will
267  * occur.
268  *
269  * Note that in general, the use of these private macros is cumulative.
270  * For example, the use of _XPG3 with no other restrictions on the X/Open
271  * namespace will make the symbols visible for XPG3 through XPG6
272  * compilation environments. The use of _XPG4_2 with no other X/Open
273  * namespace restrictions indicates that the symbols were introduced in
274  * XPG4v2 and are therefore visible for XPG4v2 through XPG6 compilation
275  * environments, but not for XPG3 or XPG4 compilation environments.
276  *
277  * _XPG3    X/Open Portability Guide, Issue 3 (XPG3)
278  * _XPG4    X/Open CAE Specification, Issue 4 (XPG4)
279  * _XPG4_2  X/Open CAE Specification, Issue 4, Version 2 (XPG4v2/UNIX 95/SUS)
280  * _XPG5    X/Open CAE Specification, Issue 5 (XPG5/UNIX 98/SUSv2)
281  * _XPG6    Open Group Technical Standard, Issue 6 (XPG6/UNIX 03/SUSv3)
282  * _XPG7    Open Group Technical Standard, Issue 7 (XPG7/UNIX 08/SUSv4)
283  */
284 
285 /* X/Open Portability Guide, Issue 3 */
286 #if defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE - 0 < 500) && \
287 	(_XOPEN_VERSION - 0 < 4) && !defined(_XOPEN_SOURCE_EXTENDED)
288 #define	_XPG3
289 /* X/Open CAE Specification, Issue 4 */
290 #elif	(defined(_XOPEN_SOURCE) && _XOPEN_VERSION - 0 == 4)
291 #define	_XPG4
292 #define	_XPG3
293 /* X/Open CAE Specification, Issue 4, Version 2 */
294 #elif (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE_EXTENDED - 0 == 1)
295 #define	_XPG4_2
296 #define	_XPG4
297 #define	_XPG3
298 /* X/Open CAE Specification, Issue 5 */
299 #elif	(_XOPEN_SOURCE - 0 == 500)
300 #define	_XPG5
301 #define	_XPG4_2
302 #define	_XPG4
303 #define	_XPG3
304 #undef	_POSIX_C_SOURCE
305 #define	_POSIX_C_SOURCE			199506L
306 /* Open Group Technical Standard , Issue 6 */
307 #elif	(_XOPEN_SOURCE - 0 == 600) || (_POSIX_C_SOURCE - 0 == 200112L)
308 #define	_XPG6
309 #define	_XPG5
310 #define	_XPG4_2
311 #define	_XPG4
312 #define	_XPG3
313 #undef	_POSIX_C_SOURCE
314 #define	_POSIX_C_SOURCE			200112L
315 #undef	_XOPEN_SOURCE
316 #define	_XOPEN_SOURCE			600
317 
318 /* Open Group Technical Standard, Issue 7 */
319 #elif	(_XOPEN_SOURCE - 0 == 700) || (_POSIX_C_SOURCE - 0 == 200809L)
320 #define	_XPG7
321 #define	_XPG6
322 #define	_XPG5
323 #define	_XPG4_2
324 #define	_XPG4
325 #define	_XPG3
326 #undef	_POSIX_C_SOURCE
327 #define	_POSIX_C_SOURCE			200809L
328 #undef	_XOPEN_SOURCE
329 #define	_XOPEN_SOURCE			700
330 #endif
331 
332 /*
333  * _XOPEN_VERSION is defined by the X/Open specifications and is not
334  * normally defined by the application, except in the case of an XPG4
335  * application.  On the implementation side, _XOPEN_VERSION defined with
336  * the value of 3 indicates an XPG3 application. _XOPEN_VERSION defined
337  * with the value of 4 indicates an XPG4 or XPG4v2 (UNIX 95) application.
338  * _XOPEN_VERSION  defined with a value of 500 indicates an XPG5 (UNIX 98)
339  * application and with a value of 600 indicates an XPG6 (UNIX 03)
340  * application and with a value of 700 indicates an XPG7 (UNIX 08).
341  * The appropriate version is determined by the use of the
342  * feature test macros described earlier.  The value of _XOPEN_VERSION
343  * defaults to 3 otherwise indicating support for XPG3 applications.
344  */
345 #ifndef _XOPEN_VERSION
346 #if	defined(_XPG7)
347 #define	_XOPEN_VERSION 700
348 #elif	defined(_XPG6)
349 #define	_XOPEN_VERSION 600
350 #elif defined(_XPG5)
351 #define	_XOPEN_VERSION 500
352 #elif	defined(_XPG4_2)
353 #define	_XOPEN_VERSION  4
354 #else
355 #define	_XOPEN_VERSION  3
356 #endif
357 #endif
358 
359 /*
360  * ANSI C and ISO 9899:1990 say the type long long doesn't exist in strictly
361  * conforming environments.  ISO 9899:1999 says it does.
362  *
363  * The presence of _LONGLONG_TYPE says "long long exists" which is therefore
364  * defined in all but strictly conforming environments that disallow it.
365  */
366 #if !defined(_STDC_C99) && defined(_STRICT_STDC) && !defined(__GNUC__)
367 /*
368  * Resist attempts to force the definition of long long in this case.
369  */
370 #if defined(_LONGLONG_TYPE)
371 #error	"No long long in strictly conforming ANSI C & 1990 ISO C environments"
372 #endif
373 #else
374 #if !defined(_LONGLONG_TYPE)
375 #define	_LONGLONG_TYPE
376 #endif
377 #endif
378 
379 /*
380  * It is invalid to compile an XPG3, XPG4, XPG4v2, or XPG5 application
381  * using c99.  The same is true for POSIX.1-1990, POSIX.2-1992, POSIX.1b,
382  * and POSIX.1c applications. Likewise, it is invalid to compile an XPG6
383  * or a POSIX.1-2001 application with anything other than a c99 or later
384  * compiler.  Therefore, we force an error in both cases.
385  */
386 #if defined(_STDC_C99) && (defined(__XOPEN_OR_POSIX) && !defined(_XPG6))
387 #error "Compiler or options invalid for pre-UNIX 03 X/Open applications \
388 	and pre-2001 POSIX applications"
389 #elif !defined(_STDC_C99) && \
390 	(defined(__XOPEN_OR_POSIX) && defined(_XPG6))
391 #error "Compiler or options invalid; UNIX 03 and POSIX.1-2001 applications \
392 	require the use of c99"
393 #endif
394 
395 /*
396  * The following macro defines a value for the ISO C99 restrict
397  * keyword so that _RESTRICT_KYWD resolves to "restrict" if
398  * an ISO C99 compiler is used, "__restrict" for c++ and "" (null string)
399  * if any other compiler is used. This allows for the use of single
400  * prototype declarations regardless of compiler version.
401  */
402 #if (defined(__STDC__) && defined(_STDC_C99))
403 #ifdef __cplusplus
404 #define	_RESTRICT_KYWD	__restrict
405 #else
406 /*
407  * NOTE: The whitespace between the '#' and 'define' is significant.
408  * It foils gcc's fixincludes from defining a redundant 'restrict'.
409  */
410 /* CSTYLED */
411 # define	_RESTRICT_KYWD	restrict
412 #endif
413 #else
414 #define	_RESTRICT_KYWD
415 #endif
416 
417 /*
418  * The following macro indicates header support for the ANSI C++
419  * standard.  The ISO/IEC designation for this is ISO/IEC FDIS 14882.
420  */
421 #define	_ISO_CPP_14882_1998
422 
423 /*
424  * The following macro indicates header support for the C99 standard,
425  * ISO/IEC 9899:1999, Programming Languages - C.
426  */
427 #define	_ISO_C_9899_1999
428 
429 /*
430  * The following macro indicates header support for DTrace. The value is an
431  * integer that corresponds to the major version number for DTrace.
432  */
433 #define	_DTRACE_VERSION	1
434 
435 #ifdef	__cplusplus
436 }
437 #endif
438 
439 #endif	/* _SYS_FEATURE_TESTS_H */
440