xref: /illumos-gate/usr/src/uts/common/sys/feature_tests.h (revision 4f364e7c95ee7fd9d5bbeddc1940e92405bb0e72)
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 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #ifndef _SYS_FEATURE_TESTS_H
28 #define	_SYS_FEATURE_TESTS_H
29 
30 #include <sys/ccompile.h>
31 #include <sys/isa_defs.h>
32 
33 #ifdef	__cplusplus
34 extern "C" {
35 #endif
36 
37 /*
38  * Values of _POSIX_C_SOURCE
39  *
40  *		undefined   not a POSIX compilation
41  *		1	    POSIX.1-1990 compilation
42  *		2	    POSIX.2-1992 compilation
43  *		199309L	    POSIX.1b-1993 compilation (Real Time)
44  *		199506L	    POSIX.1c-1995 compilation (POSIX Threads)
45  *		200112L	    POSIX.1-2001 compilation (Austin Group Revision)
46  */
47 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE)
48 #define	_POSIX_C_SOURCE 1
49 #endif
50 
51 /*
52  * The feature test macros __XOPEN_OR_POSIX, _STRICT_STDC, and _STDC_C99
53  * are Sun implementation specific macros created in order to compress
54  * common standards specified feature test macros for easier reading.
55  * These macros should not be used by the application developer as
56  * unexpected results may occur. Instead, the user should reference
57  * standards(5) for correct usage of the standards feature test macros.
58  *
59  * __XOPEN_OR_POSIX     Used in cases where a symbol is defined by both
60  *                      X/Open or POSIX or in the negative, when neither
61  *                      X/Open or POSIX defines a symbol.
62  *
63  * _STRICT_STDC         __STDC__ is specified by the C Standards and defined
64  *                      by the compiler. For Sun compilers the value of
65  *                      __STDC__ is either 1, 0, or not defined based on the
66  *                      compilation mode (see cc(1)). When the value of
67  *                      __STDC__ is 1 and in the absence of any other feature
68  *                      test macros, the namespace available to the application
69  *                      is limited to only those symbols defined by the C
70  *                      Standard. _STRICT_STDC provides a more readable means
71  *                      of identifying symbols defined by the standard, or in
72  *                      the negative, symbols that are extensions to the C
73  *                      Standard. See additional comments for GNU C differences.
74  *
75  * _STDC_C99            __STDC_VERSION__ is specified by the C standards and
76  *                      defined by the compiler and indicates the version of
77  *                      the C standard. A value of 199901L indicates a
78  *                      compiler that complies with ISO/IEC 9899:1999, other-
79  *                      wise known as the C99 standard.
80  */
81 
82 #if defined(_XOPEN_SOURCE) || defined(_POSIX_C_SOURCE)
83 #define	__XOPEN_OR_POSIX
84 #endif
85 
86 /*
87  * ISO/IEC 9899:1990 and it's revision, ISO/IEC 9899:1999 specify the
88  * following predefined macro name:
89  *
90  * __STDC__	The integer constant 1, intended to indicate a conforming
91  *		implementation.
92  *
93  * Furthermore, a strictly conforming program shall use only those features
94  * of the language and library specified in these standards. A conforming
95  * implementation shall accept any strictly conforming program.
96  *
97  * Based on these requirements, Sun's C compiler defines __STDC__ to 1 for
98  * strictly conforming environments and __STDC__ to 0 for environments that
99  * use ANSI C semantics but allow extensions to the C standard. For non-ANSI
100  * C semantics, Sun's C compiler does not define __STDC__.
101  *
102  * The GNU C project interpretation is that __STDC__ should always be defined
103  * to 1 for compilation modes that accept ANSI C syntax regardless of whether
104  * or not extensions to the C standard are used. Violations of conforming
105  * behavior are conditionally flagged as warnings via the use of the
106  * -pedantic option. In addition to defining __STDC__ to 1, the GNU C
107  * compiler also defines __STRICT_ANSI__ as a means of specifying strictly
108  * conforming environments using the -ansi or -std=<standard> options.
109  *
110  * In the absence of any other compiler options, Sun and GNU set the value
111  * of __STDC__ as follows when using the following options:
112  *
113  *				Value of __STDC__  __STRICT_ANSI__
114  *
115  * cc -Xa (default)			0	      undefined
116  * cc -Xt (transitional)		0             undefined
117  * cc -Xc (strictly conforming)		1	      undefined
118  * cc -Xs (K&R C)		    undefined	      undefined
119  *
120  * gcc (default)			1	      undefined
121  * gcc -ansi, -std={c89, c99,...)  	1              defined
122  * gcc -traditional (K&R)	    undefined	      undefined
123  *
124  * The default compilation modes for Sun C compilers versus GNU C compilers
125  * results in a differing value for __STDC__ which results in a more
126  * restricted namespace when using Sun compilers. To allow both GNU and Sun
127  * interpretations to peacefully co-exist, we use the following Sun
128  * implementation _STRICT_STDC_ macro:
129  */
130 
131 #if (__STDC__ - 0 == 1 && !defined(__GNUC__)) || \
132 	(defined(__GNUC__) && defined(__STRICT_ANSI__))
133 #define	_STRICT_STDC
134 #else
135 #undef	_STRICT_STDC
136 #endif
137 
138 /*
139  * Compiler complies with ISO/IEC 9899:1999
140  */
141 
142 #if __STDC_VERSION__ - 0 >= 199901L
143 #define	_STDC_C99
144 #endif
145 
146 /*
147  * Large file interfaces:
148  *
149  *	_LARGEFILE_SOURCE
150  *		1		large file-related additions to POSIX
151  *				interfaces requested (fseeko, etc.)
152  *	_LARGEFILE64_SOURCE
153  *		1		transitional large-file-related interfaces
154  *				requested (seek64, stat64, etc.)
155  *
156  * The corresponding announcement macros are respectively:
157  *	_LFS_LARGEFILE
158  *	_LFS64_LARGEFILE
159  * (These are set in <unistd.h>.)
160  *
161  * Requesting _LARGEFILE64_SOURCE implies requesting _LARGEFILE_SOURCE as
162  * well.
163  *
164  * The large file interfaces are made visible regardless of the initial values
165  * of the feature test macros under certain circumstances:
166  *    -	If no explicit standards-conforming environment is requested (neither
167  *	of _POSIX_SOURCE nor _XOPEN_SOURCE is defined and the value of
168  *	__STDC__ does not imply standards conformance).
169  *    -	Extended system interfaces are explicitly requested (__EXTENSIONS__
170  * 	is defined).
171  *    -	Access to in-kernel interfaces is requested (_KERNEL or _KMEMUSER is
172  *	defined).  (Note that this dependency is an artifact of the current
173  *	kernel implementation and may change in future releases.)
174  */
175 #if	(!defined(_STRICT_STDC) && !defined(__XOPEN_OR_POSIX)) || \
176 		defined(_KERNEL) || defined(_KMEMUSER) || \
177 		defined(__EXTENSIONS__)
178 #undef	_LARGEFILE64_SOURCE
179 #define	_LARGEFILE64_SOURCE	1
180 #endif
181 #if	_LARGEFILE64_SOURCE - 0 == 1
182 #undef	_LARGEFILE_SOURCE
183 #define	_LARGEFILE_SOURCE	1
184 #endif
185 
186 /*
187  * Large file compilation environment control:
188  *
189  * The setting of _FILE_OFFSET_BITS controls the size of various file-related
190  * types and governs the mapping between file-related source function symbol
191  * names and the corresponding binary entry points.
192  *
193  * In the 32-bit environment, the default value is 32; if not set, set it to
194  * the default here, to simplify tests in other headers.
195  *
196  * In the 64-bit compilation environment, the only value allowed is 64.
197  */
198 #if defined(_LP64)
199 #ifndef _FILE_OFFSET_BITS
200 #define	_FILE_OFFSET_BITS	64
201 #endif
202 #if	_FILE_OFFSET_BITS - 0 != 64
203 #error	"invalid _FILE_OFFSET_BITS value specified"
204 #endif
205 #else	/* _LP64 */
206 #ifndef	_FILE_OFFSET_BITS
207 #define	_FILE_OFFSET_BITS	32
208 #endif
209 #if	_FILE_OFFSET_BITS - 0 != 32 && _FILE_OFFSET_BITS - 0 != 64
210 #error	"invalid _FILE_OFFSET_BITS value specified"
211 #endif
212 #endif	/* _LP64 */
213 
214 /*
215  * Use of _XOPEN_SOURCE
216  *
217  * The following X/Open specifications are supported:
218  *
219  * X/Open Portability Guide, Issue 3 (XPG3)
220  * X/Open CAE Specification, Issue 4 (XPG4)
221  * X/Open CAE Specification, Issue 4, Version 2 (XPG4v2)
222  * X/Open CAE Specification, Issue 5 (XPG5)
223  * Open Group Technical Standard, Issue 6 (XPG6), also referred to as
224  *    IEEE Std. 1003.1-2001 and ISO/IEC 9945:2002.
225  *
226  * XPG4v2 is also referred to as UNIX 95 (SUS or SUSv1).
227  * XPG5 is also referred to as UNIX 98 or the Single Unix Specification,
228  *     Version 2 (SUSv2)
229  * XPG6 is the result of a merge of the X/Open and POSIX specifications
230  *     and as such is also referred to as IEEE Std. 1003.1-2001 in
231  *     addition to UNIX 03 and SUSv3.
232  *
233  * When writing a conforming X/Open application, as per the specification
234  * requirements, the appropriate feature test macros must be defined at
235  * compile time. These are as follows. For more info, see standards(5).
236  *
237  * Feature Test Macro				     Specification
238  * ------------------------------------------------  -------------
239  * _XOPEN_SOURCE                                         XPG3
240  * _XOPEN_SOURCE && _XOPEN_VERSION = 4                   XPG4
241  * _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED = 1           XPG4v2
242  * _XOPEN_SOURCE = 500                                   XPG5
243  * _XOPEN_SOURCE = 600  (or POSIX_C_SOURCE=200112L)      XPG6
244  *
245  * In order to simplify the guards within the headers, the following
246  * implementation private test macros have been created. Applications
247  * must NOT use these private test macros as unexpected results will
248  * occur.
249  *
250  * Note that in general, the use of these private macros is cumulative.
251  * For example, the use of _XPG3 with no other restrictions on the X/Open
252  * namespace will make the symbols visible for XPG3 through XPG6
253  * compilation environments. The use of _XPG4_2 with no other X/Open
254  * namespace restrictions indicates that the symbols were introduced in
255  * XPG4v2 and are therefore visible for XPG4v2 through XPG6 compilation
256  * environments, but not for XPG3 or XPG4 compilation environments.
257  *
258  * _XPG3    X/Open Portability Guide, Issue 3 (XPG3)
259  * _XPG4    X/Open CAE Specification, Issue 4 (XPG4)
260  * _XPG4_2  X/Open CAE Specification, Issue 4, Version 2 (XPG4v2/UNIX 95/SUS)
261  * _XPG5    X/Open CAE Specification, Issue 5 (XPG5/UNIX 98/SUSv2)
262  * _XPG6    Open Group Technical Standard, Issue 6 (XPG6/UNIX 03/SUSv3)
263  */
264 
265 /* X/Open Portability Guide, Issue 3 */
266 #if defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE - 0 < 500) && \
267 	(_XOPEN_VERSION - 0 < 4) && !defined(_XOPEN_SOURCE_EXTENDED)
268 #define	_XPG3
269 /* X/Open CAE Specification, Issue 4 */
270 #elif	(defined(_XOPEN_SOURCE) && _XOPEN_VERSION - 0 == 4)
271 #define	_XPG4
272 #define	_XPG3
273 /* X/Open CAE Specification, Issue 4, Version 2 */
274 #elif (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE_EXTENDED - 0 == 1)
275 #define	_XPG4_2
276 #define	_XPG4
277 #define	_XPG3
278 /* X/Open CAE Specification, Issue 5 */
279 #elif	(_XOPEN_SOURCE - 0 == 500)
280 #define	_XPG5
281 #define	_XPG4_2
282 #define	_XPG4
283 #define	_XPG3
284 #undef	_POSIX_C_SOURCE
285 #define	_POSIX_C_SOURCE			199506L
286 /* Open Group Technical Standard , Issue 6 */
287 #elif	(_XOPEN_SOURCE - 0 == 600) || (_POSIX_C_SOURCE - 0 == 200112L)
288 #define	_XPG6
289 #define	_XPG5
290 #define	_XPG4_2
291 #define	_XPG4
292 #define	_XPG3
293 #undef	_POSIX_C_SOURCE
294 #define	_POSIX_C_SOURCE			200112L
295 #undef	_XOPEN_SOURCE
296 #define	_XOPEN_SOURCE			600
297 #endif
298 
299 /*
300  * _XOPEN_VERSION is defined by the X/Open specifications and is not
301  * normally defined by the application, except in the case of an XPG4
302  * application.  On the implementation side, _XOPEN_VERSION defined with
303  * the value of 3 indicates an XPG3 application. _XOPEN_VERSION defined
304  * with the value of 4 indicates an XPG4 or XPG4v2 (UNIX 95) application.
305  * _XOPEN_VERSION  defined with a value of 500 indicates an XPG5 (UNIX 98)
306  * application and with a value of 600 indicates an XPG6 (UNIX 03)
307  * application.  The appropriate version is determined by the use of the
308  * feature test macros described earlier.  The value of _XOPEN_VERSION
309  * defaults to 3 otherwise indicating support for XPG3 applications.
310  */
311 #ifndef _XOPEN_VERSION
312 #ifdef	_XPG6
313 #define	_XOPEN_VERSION 600
314 #elif defined(_XPG5)
315 #define	_XOPEN_VERSION 500
316 #elif	defined(_XPG4_2)
317 #define	_XOPEN_VERSION  4
318 #else
319 #define	_XOPEN_VERSION  3
320 #endif
321 #endif
322 
323 /*
324  * ANSI C and ISO 9899:1990 say the type long long doesn't exist in strictly
325  * conforming environments.  ISO 9899:1999 says it does.
326  *
327  * The presence of _LONGLONG_TYPE says "long long exists" which is therefore
328  * defined in all but strictly conforming environments that disallow it.
329  */
330 #if !defined(_STDC_C99) && defined(_STRICT_STDC) && !defined(__GNUC__)
331 /*
332  * Resist attempts to force the definition of long long in this case.
333  */
334 #if defined(_LONGLONG_TYPE)
335 #error	"No long long in strictly conforming ANSI C & 1990 ISO C environments"
336 #endif
337 #else
338 #if !defined(_LONGLONG_TYPE)
339 #define	_LONGLONG_TYPE
340 #endif
341 #endif
342 
343 /*
344  * It is invalid to compile an XPG3, XPG4, XPG4v2, or XPG5 application
345  * using c99.  The same is true for POSIX.1-1990, POSIX.2-1992, POSIX.1b,
346  * and POSIX.1c applications. Likewise, it is invalid to compile an XPG6
347  * or a POSIX.1-2001 application with anything other than a c99 or later
348  * compiler.  Therefore, we force an error in both cases.
349  */
350 #if defined(_STDC_C99) && (defined(__XOPEN_OR_POSIX) && !defined(_XPG6))
351 #error "Compiler or options invalid for pre-UNIX 03 X/Open applications \
352 	and pre-2001 POSIX applications"
353 #elif !defined(_STDC_C99) && \
354 	(defined(__XOPEN_OR_POSIX) && defined(_XPG6))
355 #error "Compiler or options invalid; UNIX 03 and POSIX.1-2001 applications \
356 	require the use of c99"
357 #endif
358 
359 /*
360  * The following macro defines a value for the ISO C99 restrict
361  * keyword so that _RESTRICT_KYWD resolves to "restrict" if
362  * an ISO C99 compiler is used and "" (null string) if any other
363  * compiler is used. This allows for the use of single prototype
364  * declarations regardless of compiler version.
365  */
366 #if (defined(__STDC__) && defined(_STDC_C99)) && !defined(__cplusplus)
367 #define	_RESTRICT_KYWD	restrict
368 #else
369 #define	_RESTRICT_KYWD
370 #endif
371 
372 /*
373  * The following macro indicates header support for the ANSI C++
374  * standard.  The ISO/IEC designation for this is ISO/IEC FDIS 14882.
375  */
376 #define	_ISO_CPP_14882_1998
377 
378 /*
379  * The following macro indicates header support for the C99 standard,
380  * ISO/IEC 9899:1999, Programming Languages - C.
381  */
382 #define	_ISO_C_9899_1999
383 
384 /*
385  * The following macro indicates header support for DTrace. The value is an
386  * integer that corresponds to the major version number for DTrace.
387  */
388 #define	_DTRACE_VERSION	1
389 
390 #ifdef	__cplusplus
391 }
392 #endif
393 
394 #endif	/* _SYS_FEATURE_TESTS_H */
395