1 /* Copyright (C) 1991-2022 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 Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the 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 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _FEATURES_H 19 #define _FEATURES_H 1 20 21 /* These are defined by the user (or the compiler) 22 to specify the desired environment: 23 24 __STRICT_ANSI__ ISO Standard C. 25 _ISOC99_SOURCE Extensions to ISO C89 from ISO C99. 26 _ISOC11_SOURCE Extensions to ISO C99 from ISO C11. 27 _ISOC2X_SOURCE Extensions to ISO C99 from ISO C2X. 28 __STDC_WANT_LIB_EXT2__ 29 Extensions to ISO C99 from TR 27431-2:2010. 30 __STDC_WANT_IEC_60559_BFP_EXT__ 31 Extensions to ISO C11 from TS 18661-1:2014. 32 __STDC_WANT_IEC_60559_FUNCS_EXT__ 33 Extensions to ISO C11 from TS 18661-4:2015. 34 __STDC_WANT_IEC_60559_TYPES_EXT__ 35 Extensions to ISO C11 from TS 18661-3:2015. 36 __STDC_WANT_IEC_60559_EXT__ 37 ISO C2X interfaces defined only in Annex F. 38 39 _POSIX_SOURCE IEEE Std 1003.1. 40 _POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2; 41 if >=199309L, add IEEE Std 1003.1b-1993; 42 if >=199506L, add IEEE Std 1003.1c-1995; 43 if >=200112L, all of IEEE 1003.1-2004 44 if >=200809L, all of IEEE 1003.1-2008 45 _XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if 46 Single Unix conformance is wanted, to 600 for the 47 sixth revision, to 700 for the seventh revision. 48 _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions. 49 _LARGEFILE_SOURCE Some more functions for correct standard I/O. 50 _LARGEFILE64_SOURCE Additional functionality from LFS for large files. 51 _FILE_OFFSET_BITS=N Select default filesystem interface. 52 _ATFILE_SOURCE Additional *at interfaces. 53 _DYNAMIC_STACK_SIZE_SOURCE Select correct (but non compile-time constant) 54 MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN. 55 _GNU_SOURCE All of the above, plus GNU extensions. 56 _DEFAULT_SOURCE The default set of features (taking precedence over 57 __STRICT_ANSI__). 58 59 _FORTIFY_SOURCE Add security hardening to many library functions. 60 Set to 1 or 2; 2 performs stricter checks than 1. 61 62 _REENTRANT, _THREAD_SAFE 63 Obsolete; equivalent to _POSIX_C_SOURCE=199506L. 64 65 The `-ansi' switch to the GNU C compiler, and standards conformance 66 options such as `-std=c99', define __STRICT_ANSI__. If none of 67 these are defined, or if _DEFAULT_SOURCE is defined, the default is 68 to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to 69 200809L, as well as enabling miscellaneous functions from BSD and 70 SVID. If more than one of these are defined, they accumulate. For 71 example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together 72 give you ISO C, 1003.1, and 1003.2, but nothing else. 73 74 These are defined by this file and are used by the 75 header files to decide what to declare or define: 76 77 __GLIBC_USE (F) Define things from feature set F. This is defined 78 to 1 or 0; the subsequent macros are either defined 79 or undefined, and those tests should be moved to 80 __GLIBC_USE. 81 __USE_ISOC11 Define ISO C11 things. 82 __USE_ISOC99 Define ISO C99 things. 83 __USE_ISOC95 Define ISO C90 AMD1 (C95) things. 84 __USE_ISOCXX11 Define ISO C++11 things. 85 __USE_POSIX Define IEEE Std 1003.1 things. 86 __USE_POSIX2 Define IEEE Std 1003.2 things. 87 __USE_POSIX199309 Define IEEE Std 1003.1, and .1b things. 88 __USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things. 89 __USE_XOPEN Define XPG things. 90 __USE_XOPEN_EXTENDED Define X/Open Unix things. 91 __USE_UNIX98 Define Single Unix V2 things. 92 __USE_XOPEN2K Define XPG6 things. 93 __USE_XOPEN2KXSI Define XPG6 XSI things. 94 __USE_XOPEN2K8 Define XPG7 things. 95 __USE_XOPEN2K8XSI Define XPG7 XSI things. 96 __USE_LARGEFILE Define correct standard I/O things. 97 __USE_LARGEFILE64 Define LFS things with separate names. 98 __USE_FILE_OFFSET64 Define 64bit interface as default. 99 __USE_MISC Define things from 4.3BSD or System V Unix. 100 __USE_ATFILE Define *at interfaces and AT_* constants for them. 101 __USE_DYNAMIC_STACK_SIZE Define correct (but non compile-time constant) 102 MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN. 103 __USE_GNU Define GNU extensions. 104 __USE_FORTIFY_LEVEL Additional security measures used, according to level. 105 106 The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are 107 defined by this file unconditionally. `__GNU_LIBRARY__' is provided 108 only for compatibility. All new code should use the other symbols 109 to test for features. 110 111 All macros listed above as possibly being defined by this file are 112 explicitly undefined if they are not explicitly defined. 113 Feature-test macros that are not defined by the user or compiler 114 but are implied by the other feature-test macros defined (or by the 115 lack of any definitions) are defined by the file. 116 117 ISO C feature test macros depend on the definition of the macro 118 when an affected header is included, not when the first system 119 header is included, and so they are handled in 120 <bits/libc-header-start.h>, which does not have a multiple include 121 guard. Feature test macros that can be handled from the first 122 system header included are handled here. */ 123 124 125 /* Undefine everything, so we get a clean slate. */ 126 #undef __USE_ISOC11 127 #undef __USE_ISOC99 128 #undef __USE_ISOC95 129 #undef __USE_ISOCXX11 130 #undef __USE_POSIX 131 #undef __USE_POSIX2 132 #undef __USE_POSIX199309 133 #undef __USE_POSIX199506 134 #undef __USE_XOPEN 135 #undef __USE_XOPEN_EXTENDED 136 #undef __USE_UNIX98 137 #undef __USE_XOPEN2K 138 #undef __USE_XOPEN2KXSI 139 #undef __USE_XOPEN2K8 140 #undef __USE_XOPEN2K8XSI 141 #undef __USE_LARGEFILE 142 #undef __USE_LARGEFILE64 143 #undef __USE_FILE_OFFSET64 144 #undef __USE_MISC 145 #undef __USE_ATFILE 146 #undef __USE_DYNAMIC_STACK_SIZE 147 #undef __USE_GNU 148 #undef __USE_FORTIFY_LEVEL 149 #undef __KERNEL_STRICT_NAMES 150 #undef __GLIBC_USE_ISOC2X 151 #undef __GLIBC_USE_DEPRECATED_GETS 152 #undef __GLIBC_USE_DEPRECATED_SCANF 153 154 /* Suppress kernel-name space pollution unless user expressedly asks 155 for it. */ 156 #ifndef _LOOSE_KERNEL_NAMES 157 # define __KERNEL_STRICT_NAMES 158 #endif 159 160 /* Convenience macro to test the version of gcc. 161 Use like this: 162 #if __GNUC_PREREQ (2,8) 163 ... code requiring gcc 2.8 or later ... 164 #endif 165 Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was 166 added in 2.0. */ 167 #if defined __GNUC__ && defined __GNUC_MINOR__ 168 # define __GNUC_PREREQ(maj, min) \ 169 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) 170 #else 171 # define __GNUC_PREREQ(maj, min) 0 172 #endif 173 174 /* Similarly for clang. Features added to GCC after version 4.2 may 175 or may not also be available in clang, and clang's definitions of 176 __GNUC(_MINOR)__ are fixed at 4 and 2 respectively. Not all such 177 features can be queried via __has_extension/__has_feature. */ 178 #if defined __clang_major__ && defined __clang_minor__ 179 # define __glibc_clang_prereq(maj, min) \ 180 ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min)) 181 #else 182 # define __glibc_clang_prereq(maj, min) 0 183 #endif 184 185 /* Whether to use feature set F. */ 186 #define __GLIBC_USE(F) __GLIBC_USE_ ## F 187 188 /* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for 189 _DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not 190 issue a warning; the expectation is that the source is being 191 transitioned to use the new macro. */ 192 #if (defined _BSD_SOURCE || defined _SVID_SOURCE) \ 193 && !defined _DEFAULT_SOURCE 194 # warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" 195 # undef _DEFAULT_SOURCE 196 # define _DEFAULT_SOURCE 1 197 #endif 198 199 /* If _GNU_SOURCE was defined by the user, turn on all the other features. */ 200 #ifdef _GNU_SOURCE 201 # undef _ISOC95_SOURCE 202 # define _ISOC95_SOURCE 1 203 # undef _ISOC99_SOURCE 204 # define _ISOC99_SOURCE 1 205 # undef _ISOC11_SOURCE 206 # define _ISOC11_SOURCE 1 207 # undef _ISOC2X_SOURCE 208 # define _ISOC2X_SOURCE 1 209 # undef _POSIX_SOURCE 210 # define _POSIX_SOURCE 1 211 # undef _POSIX_C_SOURCE 212 # define _POSIX_C_SOURCE 200809L 213 # undef _XOPEN_SOURCE 214 # define _XOPEN_SOURCE 700 215 # undef _XOPEN_SOURCE_EXTENDED 216 # define _XOPEN_SOURCE_EXTENDED 1 217 # undef _LARGEFILE64_SOURCE 218 # define _LARGEFILE64_SOURCE 1 219 # undef _DEFAULT_SOURCE 220 # define _DEFAULT_SOURCE 1 221 # undef _ATFILE_SOURCE 222 # define _ATFILE_SOURCE 1 223 # undef _DYNAMIC_STACK_SIZE_SOURCE 224 # define _DYNAMIC_STACK_SIZE_SOURCE 1 225 #endif 226 227 /* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined, 228 define _DEFAULT_SOURCE. */ 229 #if (defined _DEFAULT_SOURCE \ 230 || (!defined __STRICT_ANSI__ \ 231 && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \ 232 && !defined _ISOC2X_SOURCE \ 233 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \ 234 && !defined _XOPEN_SOURCE)) 235 # undef _DEFAULT_SOURCE 236 # define _DEFAULT_SOURCE 1 237 #endif 238 239 /* This is to enable the ISO C2X extension. */ 240 #if (defined _ISOC2X_SOURCE \ 241 || (defined __STDC_VERSION__ && __STDC_VERSION__ > 201710L)) 242 # define __GLIBC_USE_ISOC2X 1 243 #else 244 # define __GLIBC_USE_ISOC2X 0 245 #endif 246 247 /* This is to enable the ISO C11 extension. */ 248 #if (defined _ISOC11_SOURCE || defined _ISOC2X_SOURCE \ 249 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L)) 250 # define __USE_ISOC11 1 251 #endif 252 253 /* This is to enable the ISO C99 extension. */ 254 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ 255 || defined _ISOC2X_SOURCE \ 256 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)) 257 # define __USE_ISOC99 1 258 #endif 259 260 /* This is to enable the ISO C90 Amendment 1:1995 extension. */ 261 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ 262 || defined _ISOC2X_SOURCE \ 263 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L)) 264 # define __USE_ISOC95 1 265 #endif 266 267 #ifdef __cplusplus 268 /* This is to enable compatibility for ISO C++17. */ 269 # if __cplusplus >= 201703L 270 # define __USE_ISOC11 1 271 # endif 272 /* This is to enable compatibility for ISO C++11. 273 Check the temporary macro for now, too. */ 274 # if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__ 275 # define __USE_ISOCXX11 1 276 # define __USE_ISOC99 1 277 # endif 278 #endif 279 280 /* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE 281 is defined, use POSIX.1-2008 (or another version depending on 282 _XOPEN_SOURCE). */ 283 #ifdef _DEFAULT_SOURCE 284 # if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE 285 # define __USE_POSIX_IMPLICITLY 1 286 # endif 287 # undef _POSIX_SOURCE 288 # define _POSIX_SOURCE 1 289 # undef _POSIX_C_SOURCE 290 # define _POSIX_C_SOURCE 200809L 291 #endif 292 293 #if ((!defined __STRICT_ANSI__ \ 294 || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \ 295 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE) 296 # define _POSIX_SOURCE 1 297 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500 298 # define _POSIX_C_SOURCE 2 299 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600 300 # define _POSIX_C_SOURCE 199506L 301 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700 302 # define _POSIX_C_SOURCE 200112L 303 # else 304 # define _POSIX_C_SOURCE 200809L 305 # endif 306 # define __USE_POSIX_IMPLICITLY 1 307 #endif 308 309 /* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be 310 defined in all multithreaded code. GNU libc has not required this 311 for many years. We now treat them as compatibility synonyms for 312 _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with 313 comprehensive support for multithreaded code. Using them never 314 lowers the selected level of POSIX conformance, only raises it. */ 315 #if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \ 316 && (defined _REENTRANT || defined _THREAD_SAFE)) 317 # define _POSIX_SOURCE 1 318 # undef _POSIX_C_SOURCE 319 # define _POSIX_C_SOURCE 199506L 320 #endif 321 322 #if (defined _POSIX_SOURCE \ 323 || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \ 324 || defined _XOPEN_SOURCE) 325 # define __USE_POSIX 1 326 #endif 327 328 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE 329 # define __USE_POSIX2 1 330 #endif 331 332 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L 333 # define __USE_POSIX199309 1 334 #endif 335 336 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L 337 # define __USE_POSIX199506 1 338 #endif 339 340 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L 341 # define __USE_XOPEN2K 1 342 # undef __USE_ISOC95 343 # define __USE_ISOC95 1 344 # undef __USE_ISOC99 345 # define __USE_ISOC99 1 346 #endif 347 348 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L 349 # define __USE_XOPEN2K8 1 350 # undef _ATFILE_SOURCE 351 # define _ATFILE_SOURCE 1 352 #endif 353 354 #ifdef _XOPEN_SOURCE 355 # define __USE_XOPEN 1 356 # if (_XOPEN_SOURCE - 0) >= 500 357 # define __USE_XOPEN_EXTENDED 1 358 # define __USE_UNIX98 1 359 # undef _LARGEFILE_SOURCE 360 # define _LARGEFILE_SOURCE 1 361 # if (_XOPEN_SOURCE - 0) >= 600 362 # if (_XOPEN_SOURCE - 0) >= 700 363 # define __USE_XOPEN2K8 1 364 # define __USE_XOPEN2K8XSI 1 365 # endif 366 # define __USE_XOPEN2K 1 367 # define __USE_XOPEN2KXSI 1 368 # undef __USE_ISOC95 369 # define __USE_ISOC95 1 370 # undef __USE_ISOC99 371 # define __USE_ISOC99 1 372 # endif 373 # else 374 # ifdef _XOPEN_SOURCE_EXTENDED 375 # define __USE_XOPEN_EXTENDED 1 376 # endif 377 # endif 378 #endif 379 380 #ifdef _LARGEFILE_SOURCE 381 # define __USE_LARGEFILE 1 382 #endif 383 384 #ifdef _LARGEFILE64_SOURCE 385 # define __USE_LARGEFILE64 1 386 #endif 387 388 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64 389 # define __USE_FILE_OFFSET64 1 390 #endif 391 392 #include <features-time64.h> 393 394 #if defined _DEFAULT_SOURCE 395 # define __USE_MISC 1 396 #endif 397 398 #ifdef _ATFILE_SOURCE 399 # define __USE_ATFILE 1 400 #endif 401 402 #ifdef _DYNAMIC_STACK_SIZE_SOURCE 403 # define __USE_DYNAMIC_STACK_SIZE 1 404 #endif 405 406 #ifdef _GNU_SOURCE 407 # define __USE_GNU 1 408 #endif 409 410 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 411 # if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0 412 # warning _FORTIFY_SOURCE requires compiling with optimization (-O) 413 # elif !__GNUC_PREREQ (4, 1) 414 # warning _FORTIFY_SOURCE requires GCC 4.1 or later 415 # elif _FORTIFY_SOURCE > 2 && (__glibc_clang_prereq (9, 0) \ 416 || __GNUC_PREREQ (12, 0)) 417 418 # if _FORTIFY_SOURCE > 3 419 # warning _FORTIFY_SOURCE > 3 is treated like 3 on this platform 420 # endif 421 # define __USE_FORTIFY_LEVEL 3 422 # elif _FORTIFY_SOURCE > 1 423 # if _FORTIFY_SOURCE > 2 424 # warning _FORTIFY_SOURCE > 2 is treated like 2 on this platform 425 # endif 426 # define __USE_FORTIFY_LEVEL 2 427 # else 428 # define __USE_FORTIFY_LEVEL 1 429 # endif 430 #endif 431 #ifndef __USE_FORTIFY_LEVEL 432 # define __USE_FORTIFY_LEVEL 0 433 #endif 434 435 /* The function 'gets' existed in C89, but is impossible to use 436 safely. It has been removed from ISO C11 and ISO C++14. Note: for 437 compatibility with various implementations of <cstdio>, this test 438 must consider only the value of __cplusplus when compiling C++. */ 439 #if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11 440 # define __GLIBC_USE_DEPRECATED_GETS 0 441 #else 442 # define __GLIBC_USE_DEPRECATED_GETS 1 443 #endif 444 445 /* GNU formerly extended the scanf functions with modified format 446 specifiers %as, %aS, and %a[...] that allocate a buffer for the 447 input using malloc. This extension conflicts with ISO C99, which 448 defines %a as a standalone format specifier that reads a floating- 449 point number; moreover, POSIX.1-2008 provides the same feature 450 using the modifier letter 'm' instead (%ms, %mS, %m[...]). 451 452 We now follow C99 unless GNU extensions are active and the compiler 453 is specifically in C89 or C++98 mode (strict or not). For 454 instance, with GCC, -std=gnu11 will have C99-compliant scanf with 455 or without -D_GNU_SOURCE, but -std=c89 -D_GNU_SOURCE will have the 456 old extension. */ 457 #if (defined __USE_GNU \ 458 && (defined __cplusplus \ 459 ? (__cplusplus < 201103L && !defined __GXX_EXPERIMENTAL_CXX0X__) \ 460 : (!defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L))) 461 # define __GLIBC_USE_DEPRECATED_SCANF 1 462 #else 463 # define __GLIBC_USE_DEPRECATED_SCANF 0 464 #endif 465 466 /* Get definitions of __STDC_* predefined macros, if the compiler has 467 not preincluded this header automatically. */ 468 #include <stdc-predef.h> 469 470 /* This macro indicates that the installed library is the GNU C Library. 471 For historic reasons the value now is 6 and this will stay from now 472 on. The use of this variable is deprecated. Use __GLIBC__ and 473 __GLIBC_MINOR__ now (see below) when you want to test for a specific 474 GNU C library version and use the values in <gnu/lib-names.h> to get 475 the sonames of the shared libraries. */ 476 #undef __GNU_LIBRARY__ 477 #define __GNU_LIBRARY__ 6 478 479 /* Major and minor version number of the GNU C library package. Use 480 these macros to test for features in specific releases. */ 481 #define __GLIBC__ 2 482 #define __GLIBC_MINOR__ 36 483 484 #define __GLIBC_PREREQ(maj, min) \ 485 ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min)) 486 487 /* This is here only because every header file already includes this one. */ 488 #ifndef __ASSEMBLER__ 489 # ifndef _SYS_CDEFS_H 490 # include <sys/cdefs.h> 491 # endif 492 493 /* If we don't have __REDIRECT, prototypes will be missing if 494 __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */ 495 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT 496 # define __USE_LARGEFILE 1 497 # define __USE_LARGEFILE64 1 498 # endif 499 500 #endif /* !ASSEMBLER */ 501 502 /* Decide whether we can define 'extern inline' functions in headers. */ 503 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \ 504 && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \ 505 && defined __extern_inline 506 # define __USE_EXTERN_INLINES 1 507 #endif 508 509 510 /* This is here only because every header file already includes this one. 511 Get the definitions of all the appropriate `__stub_FUNCTION' symbols. 512 <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub 513 that will always return failure (and set errno to ENOSYS). */ 514 #include <gnu/stubs.h> 515 516 517 #endif /* features.h */ 518