ICU 72.1 72.1
platform.h
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1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4******************************************************************************
5*
6* Copyright (C) 1997-2016, International Business Machines
7* Corporation and others. All Rights Reserved.
8*
9******************************************************************************
10*
11* FILE NAME : platform.h
12*
13* Date Name Description
14* 05/13/98 nos Creation (content moved here from ptypes.h).
15* 03/02/99 stephen Added AS400 support.
16* 03/30/99 stephen Added Linux support.
17* 04/13/99 stephen Reworked for autoconf.
18******************************************************************************
19*/
20
21#ifndef _PLATFORM_H
22#define _PLATFORM_H
23
24#include "unicode/uconfig.h"
25#include "unicode/uvernum.h"
26
59#ifdef U_IN_DOXYGEN
60/*
61 * Problem: "platform.h:335: warning: documentation for unknown define U_HAVE_STD_STRING found." means that U_HAVE_STD_STRING is not documented.
62 * Solution: #define any defines for non @internal API here, so that they are visible in the docs. If you just set PREDEFINED in Doxyfile.in, they won't be documented.
63 */
64
65/* None for now. */
66#endif
67
89#define U_PF_UNKNOWN 0
91#define U_PF_WINDOWS 1000
93#define U_PF_MINGW 1800
99#define U_PF_CYGWIN 1900
100/* Reserve 2000 for U_PF_UNIX? */
102#define U_PF_HPUX 2100
104#define U_PF_SOLARIS 2600
106#define U_PF_BSD 3000
108#define U_PF_AIX 3100
110#define U_PF_IRIX 3200
119#define U_PF_DARWIN 3500
121#define U_PF_IPHONE 3550
123#define U_PF_QNX 3700
125#define U_PF_LINUX 4000
132#define U_PF_BROWSER_NATIVE_CLIENT 4020
134#define U_PF_ANDROID 4050
136#define U_PF_FUCHSIA 4100
137/* Maximum value for Linux-based platform is 4499 */
145#define U_PF_EMSCRIPTEN 5010
147#define U_PF_OS390 9000
149#define U_PF_OS400 9400
150
151#ifdef U_PLATFORM
152 /* Use the predefined value. */
153#elif defined(__MINGW32__)
154# define U_PLATFORM U_PF_MINGW
155#elif defined(__CYGWIN__)
156# define U_PLATFORM U_PF_CYGWIN
157#elif defined(WIN32) || defined(_WIN32) || defined(WIN64) || defined(_WIN64)
158# define U_PLATFORM U_PF_WINDOWS
159#elif defined(__ANDROID__)
160# define U_PLATFORM U_PF_ANDROID
161 /* Android wchar_t support depends on the API level. */
162# include <android/api-level.h>
163#elif defined(__pnacl__) || defined(__native_client__)
164# define U_PLATFORM U_PF_BROWSER_NATIVE_CLIENT
165#elif defined(__Fuchsia__)
166# define U_PLATFORM U_PF_FUCHSIA
167#elif defined(linux) || defined(__linux__) || defined(__linux)
168# define U_PLATFORM U_PF_LINUX
169#elif defined(__APPLE__) && defined(__MACH__)
170# include <TargetConditionals.h>
171# if (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && (defined(TARGET_OS_MACCATALYST) && !TARGET_OS_MACCATALYST) /* variant of TARGET_OS_MAC */
172# define U_PLATFORM U_PF_IPHONE
173# else
174# define U_PLATFORM U_PF_DARWIN
175# endif
176#elif defined(BSD) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__MirBSD__)
177# if defined(__FreeBSD__)
178# include <sys/endian.h>
179# endif
180# define U_PLATFORM U_PF_BSD
181#elif defined(sun) || defined(__sun)
182 /* Check defined(__SVR4) || defined(__svr4__) to distinguish Solaris from SunOS? */
183# define U_PLATFORM U_PF_SOLARIS
184# if defined(__GNUC__)
185 /* Solaris/GCC needs this header file to get the proper endianness. Normally, this
186 * header file is included with stddef.h but on Solairs/GCC, the GCC version of stddef.h
187 * is included which does not include this header file.
188 */
189# include <sys/isa_defs.h>
190# endif
191#elif defined(_AIX) || defined(__TOS_AIX__)
192# define U_PLATFORM U_PF_AIX
193#elif defined(_hpux) || defined(hpux) || defined(__hpux)
194# define U_PLATFORM U_PF_HPUX
195#elif defined(sgi) || defined(__sgi)
196# define U_PLATFORM U_PF_IRIX
197#elif defined(__QNX__) || defined(__QNXNTO__)
198# define U_PLATFORM U_PF_QNX
199#elif defined(__TOS_MVS__)
200# define U_PLATFORM U_PF_OS390
201#elif defined(__OS400__) || defined(__TOS_OS400__)
202# define U_PLATFORM U_PF_OS400
203#elif defined(__EMSCRIPTEN__)
204# define U_PLATFORM U_PF_EMSCRIPTEN
205#else
206# define U_PLATFORM U_PF_UNKNOWN
207#endif
208
215/* Commented out because this is already set in mh-cygwin-msvc
216#if U_PLATFORM == U_PF_CYGWIN && defined(_MSC_VER)
217# define CYGWINMSVC
218#endif
219*/
220#ifdef U_IN_DOXYGEN
221# define CYGWINMSVC
222#endif
223
230#ifdef U_PLATFORM_USES_ONLY_WIN32_API
231 /* Use the predefined value. */
232#elif (U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_MINGW) || defined(CYGWINMSVC)
233# define U_PLATFORM_USES_ONLY_WIN32_API 1
234#else
235 /* Cygwin implements POSIX. */
236# define U_PLATFORM_USES_ONLY_WIN32_API 0
237#endif
238
245#ifdef U_PLATFORM_HAS_WIN32_API
246 /* Use the predefined value. */
247#elif U_PF_WINDOWS <= U_PLATFORM && U_PLATFORM <= U_PF_CYGWIN
248# define U_PLATFORM_HAS_WIN32_API 1
249#else
250# define U_PLATFORM_HAS_WIN32_API 0
251#endif
252
259#ifdef U_PLATFORM_HAS_WINUWP_API
260 /* Use the predefined value. */
261#else
262# define U_PLATFORM_HAS_WINUWP_API 0
263#endif
264
271#ifdef U_PLATFORM_IMPLEMENTS_POSIX
272 /* Use the predefined value. */
273#elif U_PLATFORM_USES_ONLY_WIN32_API
274# define U_PLATFORM_IMPLEMENTS_POSIX 0
275#else
276# define U_PLATFORM_IMPLEMENTS_POSIX 1
277#endif
278
284#ifdef U_PLATFORM_IS_LINUX_BASED
285 /* Use the predefined value. */
286#elif U_PF_LINUX <= U_PLATFORM && U_PLATFORM <= 4499
287# define U_PLATFORM_IS_LINUX_BASED 1
288#else
289# define U_PLATFORM_IS_LINUX_BASED 0
290#endif
291
297#ifdef U_PLATFORM_IS_DARWIN_BASED
298 /* Use the predefined value. */
299#elif U_PF_DARWIN <= U_PLATFORM && U_PLATFORM <= U_PF_IPHONE
300# define U_PLATFORM_IS_DARWIN_BASED 1
301#else
302# define U_PLATFORM_IS_DARWIN_BASED 0
303#endif
304
312#ifdef U_HAVE_STDINT_H
313 /* Use the predefined value. */
314#elif U_PLATFORM_USES_ONLY_WIN32_API
315# if defined(__BORLANDC__) || U_PLATFORM == U_PF_MINGW || (defined(_MSC_VER) && _MSC_VER>=1600)
316 /* Windows Visual Studio 9 and below do not have stdint.h & inttypes.h, but VS 2010 adds them. */
317# define U_HAVE_STDINT_H 1
318# else
319# define U_HAVE_STDINT_H 0
320# endif
321#elif U_PLATFORM == U_PF_SOLARIS
322 /* Solaris has inttypes.h but not stdint.h. */
323# define U_HAVE_STDINT_H 0
324#elif U_PLATFORM == U_PF_AIX && !defined(_AIX51) && defined(_POWER)
325 /* PPC AIX <= 4.3 has inttypes.h but not stdint.h. */
326# define U_HAVE_STDINT_H 0
327#else
328# define U_HAVE_STDINT_H 1
329#endif
330
337#ifdef U_HAVE_INTTYPES_H
338 /* Use the predefined value. */
339#elif U_PLATFORM == U_PF_SOLARIS
340 /* Solaris has inttypes.h but not stdint.h. */
341# define U_HAVE_INTTYPES_H 1
342#elif U_PLATFORM == U_PF_AIX && !defined(_AIX51) && defined(_POWER)
343 /* PPC AIX <= 4.3 has inttypes.h but not stdint.h. */
344# define U_HAVE_INTTYPES_H 1
345#else
346 /* Most platforms have both inttypes.h and stdint.h, or neither. */
347# define U_HAVE_INTTYPES_H U_HAVE_STDINT_H
348#endif
349
350/*===========================================================================*/
352/*===========================================================================*/
353
364#ifdef __GNUC__
365# define U_GCC_MAJOR_MINOR (__GNUC__ * 100 + __GNUC_MINOR__)
366#else
367# define U_GCC_MAJOR_MINOR 0
368#endif
369
375#ifdef U_IS_BIG_ENDIAN
376 /* Use the predefined value. */
377#elif defined(BYTE_ORDER) && defined(BIG_ENDIAN)
378# define U_IS_BIG_ENDIAN (BYTE_ORDER == BIG_ENDIAN)
379#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__)
380 /* gcc */
381# define U_IS_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
382#elif defined(__BIG_ENDIAN__) || defined(_BIG_ENDIAN)
383# define U_IS_BIG_ENDIAN 1
384#elif defined(__LITTLE_ENDIAN__) || defined(_LITTLE_ENDIAN)
385# define U_IS_BIG_ENDIAN 0
386#elif U_PLATFORM == U_PF_OS390 || U_PLATFORM == U_PF_OS400 || defined(__s390__) || defined(__s390x__)
387 /* These platforms do not appear to predefine any endianness macros. */
388# define U_IS_BIG_ENDIAN 1
389#elif defined(_PA_RISC1_0) || defined(_PA_RISC1_1) || defined(_PA_RISC2_0)
390 /* HPPA do not appear to predefine any endianness macros. */
391# define U_IS_BIG_ENDIAN 1
392#elif defined(sparc) || defined(__sparc) || defined(__sparc__)
393 /* Some sparc based systems (e.g. Linux) do not predefine any endianness macros. */
394# define U_IS_BIG_ENDIAN 1
395#else
396# define U_IS_BIG_ENDIAN 0
397#endif
398
404#ifdef U_HAVE_PLACEMENT_NEW
405 /* Use the predefined value. */
406#elif defined(__BORLANDC__)
407# define U_HAVE_PLACEMENT_NEW 0
408#else
409# define U_HAVE_PLACEMENT_NEW 1
410#endif
411
418#ifdef U_HAVE_DEBUG_LOCATION_NEW
419 /* Use the predefined value. */
420#elif defined(_MSC_VER)
421# define U_HAVE_DEBUG_LOCATION_NEW 1
422#else
423# define U_HAVE_DEBUG_LOCATION_NEW 0
424#endif
425
426/* Compatibility with compilers other than clang: http://clang.llvm.org/docs/LanguageExtensions.html */
427#ifdef __has_attribute
428# define UPRV_HAS_ATTRIBUTE(x) __has_attribute(x)
429#else
430# define UPRV_HAS_ATTRIBUTE(x) 0
431#endif
432#ifdef __has_cpp_attribute
433# define UPRV_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
434#else
435# define UPRV_HAS_CPP_ATTRIBUTE(x) 0
436#endif
437#ifdef __has_declspec_attribute
438# define UPRV_HAS_DECLSPEC_ATTRIBUTE(x) __has_declspec_attribute(x)
439#else
440# define UPRV_HAS_DECLSPEC_ATTRIBUTE(x) 0
441#endif
442#ifdef __has_builtin
443# define UPRV_HAS_BUILTIN(x) __has_builtin(x)
444#else
445# define UPRV_HAS_BUILTIN(x) 0
446#endif
447#ifdef __has_feature
448# define UPRV_HAS_FEATURE(x) __has_feature(x)
449#else
450# define UPRV_HAS_FEATURE(x) 0
451#endif
452#ifdef __has_extension
453# define UPRV_HAS_EXTENSION(x) __has_extension(x)
454#else
455# define UPRV_HAS_EXTENSION(x) 0
456#endif
457#ifdef __has_warning
458# define UPRV_HAS_WARNING(x) __has_warning(x)
459#else
460# define UPRV_HAS_WARNING(x) 0
461#endif
462
468#if defined(__GNUC__) && __GNUC__>=3
469# define U_MALLOC_ATTR __attribute__ ((__malloc__))
470#else
471# define U_MALLOC_ATTR
472#endif
473
479#if (defined(__GNUC__) && \
480 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))) || \
481 UPRV_HAS_ATTRIBUTE(alloc_size)
482# define U_ALLOC_SIZE_ATTR(X) __attribute__ ((alloc_size(X)))
483# define U_ALLOC_SIZE_ATTR2(X,Y) __attribute__ ((alloc_size(X,Y)))
484#else
485# define U_ALLOC_SIZE_ATTR(X)
486# define U_ALLOC_SIZE_ATTR2(X,Y)
487#endif
488
495#ifdef U_CPLUSPLUS_VERSION
496# if U_CPLUSPLUS_VERSION != 0 && !defined(__cplusplus)
497# undef U_CPLUSPLUS_VERSION
498# define U_CPLUSPLUS_VERSION 0
499# endif
500 /* Otherwise use the predefined value. */
501#elif !defined(__cplusplus)
502# define U_CPLUSPLUS_VERSION 0
503#elif __cplusplus >= 201402L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201402L)
504# define U_CPLUSPLUS_VERSION 14
505#elif __cplusplus >= 201103L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201103L)
506# define U_CPLUSPLUS_VERSION 11
507#else
508 // C++98 or C++03
509# define U_CPLUSPLUS_VERSION 1
510#endif
511
512#if (U_PLATFORM == U_PF_AIX || U_PLATFORM == U_PF_OS390) && defined(__cplusplus) &&(U_CPLUSPLUS_VERSION < 11)
513// add in std::nullptr_t
514namespace std {
515 typedef decltype(nullptr) nullptr_t;
516};
517#endif
518
526#ifdef U_NOEXCEPT
527 /* Use the predefined value. */
528#else
529# define U_NOEXCEPT noexcept
530#endif
531
538#ifndef __cplusplus
539 // Not for C.
540#elif defined(U_FALLTHROUGH)
541 // Use the predefined value.
542#elif defined(__clang__)
543 // Test for compiler vs. feature separately.
544 // Other compilers might choke on the feature test.
545# if UPRV_HAS_CPP_ATTRIBUTE(clang::fallthrough) || \
546 (UPRV_HAS_FEATURE(cxx_attributes) && \
547 UPRV_HAS_WARNING("-Wimplicit-fallthrough"))
548# define U_FALLTHROUGH [[clang::fallthrough]]
549# endif
550#elif defined(__GNUC__) && (__GNUC__ >= 7)
551# define U_FALLTHROUGH __attribute__((fallthrough))
552#endif
553
554#ifndef U_FALLTHROUGH
555# define U_FALLTHROUGH
556#endif
557
560/*===========================================================================*/
562/*===========================================================================*/
563
568#define U_ASCII_FAMILY 0
569
574#define U_EBCDIC_FAMILY 1
575
618#ifdef U_CHARSET_FAMILY
619 /* Use the predefined value. */
620#elif U_PLATFORM == U_PF_OS390 && (!defined(__CHARSET_LIB) || !__CHARSET_LIB)
621# define U_CHARSET_FAMILY U_EBCDIC_FAMILY
622#elif U_PLATFORM == U_PF_OS400 && !defined(__UTF32__)
623# define U_CHARSET_FAMILY U_EBCDIC_FAMILY
624#else
625# define U_CHARSET_FAMILY U_ASCII_FAMILY
626#endif
627
648#ifdef U_CHARSET_IS_UTF8
649 /* Use the predefined value. */
650#elif U_PLATFORM_IS_LINUX_BASED || U_PLATFORM_IS_DARWIN_BASED || \
651 U_PLATFORM == U_PF_EMSCRIPTEN
652# define U_CHARSET_IS_UTF8 1
653#else
654# define U_CHARSET_IS_UTF8 0
655#endif
656
659/*===========================================================================*/
661/*===========================================================================*/
662
669#ifdef U_HAVE_WCHAR_H
670 /* Use the predefined value. */
671#elif U_PLATFORM == U_PF_ANDROID && __ANDROID_API__ < 9
672 /*
673 * Android before Gingerbread (Android 2.3, API level 9) did not support wchar_t.
674 * The type and header existed, but the library functions did not work as expected.
675 * The size of wchar_t was 1 but L"xyz" string literals had 32-bit units anyway.
676 */
677# define U_HAVE_WCHAR_H 0
678#else
679# define U_HAVE_WCHAR_H 1
680#endif
681
688#ifdef U_SIZEOF_WCHAR_T
689 /* Use the predefined value. */
690#elif (U_PLATFORM == U_PF_ANDROID && __ANDROID_API__ < 9)
691 /*
692 * Classic Mac OS and Mac OS X before 10.3 (Panther) did not support wchar_t or wstring.
693 * Newer Mac OS X has size 4.
694 */
695# define U_SIZEOF_WCHAR_T 1
696#elif U_PLATFORM_HAS_WIN32_API || U_PLATFORM == U_PF_CYGWIN
697# define U_SIZEOF_WCHAR_T 2
698#elif U_PLATFORM == U_PF_AIX
699 /*
700 * AIX 6.1 information, section "Wide character data representation":
701 * "... the wchar_t datatype is 32-bit in the 64-bit environment and
702 * 16-bit in the 32-bit environment."
703 * and
704 * "All locales use Unicode for their wide character code values (process code),
705 * except the IBM-eucTW codeset."
706 */
707# ifdef __64BIT__
708# define U_SIZEOF_WCHAR_T 4
709# else
710# define U_SIZEOF_WCHAR_T 2
711# endif
712#elif U_PLATFORM == U_PF_OS390
713 /*
714 * z/OS V1R11 information center, section "LP64 | ILP32":
715 * "In 31-bit mode, the size of long and pointers is 4 bytes and the size of wchar_t is 2 bytes.
716 * Under LP64, the size of long and pointer is 8 bytes and the size of wchar_t is 4 bytes."
717 */
718# ifdef _LP64
719# define U_SIZEOF_WCHAR_T 4
720# else
721# define U_SIZEOF_WCHAR_T 2
722# endif
723#elif U_PLATFORM == U_PF_OS400
724# if defined(__UTF32__)
725 /*
726 * LOCALETYPE(*LOCALEUTF) is specified.
727 * Wide-character strings are in UTF-32,
728 * narrow-character strings are in UTF-8.
729 */
730# define U_SIZEOF_WCHAR_T 4
731# elif defined(__UCS2__)
732 /*
733 * LOCALETYPE(*LOCALEUCS2) is specified.
734 * Wide-character strings are in UCS-2,
735 * narrow-character strings are in EBCDIC.
736 */
737# define U_SIZEOF_WCHAR_T 2
738# else
739 /*
740 * LOCALETYPE(*CLD) or LOCALETYPE(*LOCALE) is specified.
741 * Wide-character strings are in 16-bit EBCDIC,
742 * narrow-character strings are in EBCDIC.
743 */
744# define U_SIZEOF_WCHAR_T 2
745# endif
746#else
747# define U_SIZEOF_WCHAR_T 4
748#endif
749
750#ifndef U_HAVE_WCSCPY
751#define U_HAVE_WCSCPY U_HAVE_WCHAR_H
752#endif
753
764#ifdef U_HAVE_CHAR16_T
765 /* Use the predefined value. */
766#else
767 /*
768 * Notes:
769 * Visual Studio 2010 (_MSC_VER==1600) defines char16_t as a typedef
770 * and does not support u"abc" string literals.
771 * Visual Studio 2015 (_MSC_VER>=1900) and above adds support for
772 * both char16_t and u"abc" string literals.
773 * gcc 4.4 defines the __CHAR16_TYPE__ macro to a usable type but
774 * does not support u"abc" string literals.
775 * C++11 and C11 require support for UTF-16 literals
776 * TODO: Fix for plain C. Doesn't work on Mac.
777 */
778# if U_CPLUSPLUS_VERSION >= 11 || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L)
779# define U_HAVE_CHAR16_T 1
780# else
781# define U_HAVE_CHAR16_T 0
782# endif
783#endif
784
792#ifdef U_DECLARE_UTF16
793 /* Use the predefined value. */
794#elif U_HAVE_CHAR16_T \
795 || (defined(__xlC__) && defined(__IBM_UTF_LITERAL) && U_SIZEOF_WCHAR_T != 2) \
796 || (defined(__HP_aCC) && __HP_aCC >= 035000) \
797 || (defined(__HP_cc) && __HP_cc >= 111106) \
798 || (defined(U_IN_DOXYGEN))
799# define U_DECLARE_UTF16(string) u ## string
800#elif U_SIZEOF_WCHAR_T == 2 \
801 && (U_CHARSET_FAMILY == 0 || (U_PF_OS390 <= U_PLATFORM && U_PLATFORM <= U_PF_OS400 && defined(__UCS2__)))
802# define U_DECLARE_UTF16(string) L ## string
803#else
804 /* Leave U_DECLARE_UTF16 undefined. See unistr.h. */
805#endif
806
809/*===========================================================================*/
811/*===========================================================================*/
812
813#ifdef U_EXPORT
814 /* Use the predefined value. */
815#elif defined(U_STATIC_IMPLEMENTATION)
816# define U_EXPORT
817#elif defined(_MSC_VER) || (UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllexport__) && \
818 UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllimport__))
819# define U_EXPORT __declspec(dllexport)
820#elif defined(__GNUC__)
821# define U_EXPORT __attribute__((visibility("default")))
822#elif (defined(__SUNPRO_CC) && __SUNPRO_CC >= 0x550) \
823 || (defined(__SUNPRO_C) && __SUNPRO_C >= 0x550)
824# define U_EXPORT __global
825/*#elif defined(__HP_aCC) || defined(__HP_cc)
826# define U_EXPORT __declspec(dllexport)*/
827#else
828# define U_EXPORT
829#endif
830
831/* U_CALLCONV is related to U_EXPORT2 */
832#ifdef U_EXPORT2
833 /* Use the predefined value. */
834#elif defined(_MSC_VER)
835# define U_EXPORT2 __cdecl
836#else
837# define U_EXPORT2
838#endif
839
840#ifdef U_IMPORT
841 /* Use the predefined value. */
842#elif defined(_MSC_VER) || (UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllexport__) && \
843 UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllimport__))
844 /* Windows needs to export/import data. */
845# define U_IMPORT __declspec(dllimport)
846#else
847# define U_IMPORT
848#endif
849
857#ifdef U_HIDDEN
858 /* Use the predefined value. */
859#elif defined(__GNUC__)
860# define U_HIDDEN __attribute__((visibility("hidden")))
861#else
862# define U_HIDDEN
863#endif
864
882#if U_PLATFORM == U_PF_OS390 && defined(__cplusplus)
883# define U_CALLCONV __cdecl
884#else
885# define U_CALLCONV U_EXPORT2
886#endif
887
893#if U_PLATFORM == U_PF_OS390 && defined(__cplusplus)
894# define U_CALLCONV_FPTR U_CALLCONV
895#else
896# define U_CALLCONV_FPTR
897#endif
900#endif // _PLATFORM_H
User-configurable settings.
C API: definitions of ICU version numbers.