/* libc/sys/linux/sys/cdefs.h - Helper macros for K&R vs. ANSI C compat. */
  
  /* Written 2000 by Werner Almesberger */
  
  /*-
   * Copyright (c) 1991, 1993
   *  The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software contributed to Berkeley by
   * Berkeley Software Design, Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *  @(#)cdefs.h 8.8 (Berkeley) 1/9/95
   * $FreeBSD$
   */
  
  /* This file was imported into RIOT from newlib 2.3.0 */
  
  #ifndef SYS_CDEFS_H
  #define SYS_CDEFS_H
  
  #include <sys/features.h>
  #include <stddef.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #define __PMT(args) args
  #define __DOTS      , ...
  #define __THROW
  
  #ifdef __GNUC__
  # define __ASMNAME(cname)  __XSTRING (__USER_LABEL_PREFIX__) cname
  #endif
  
  #define __ptr_t void *
  #define __long_double_t  long double
  
  #define __attribute_malloc__
  #define __attribute_pure__
  #define __attribute_format_strfmon__(a,b)
  #define __flexarr      [0]
  
  #ifndef __BOUNDED_POINTERS__
  # define __bounded      /* nothing */
  # define __unbounded    /* nothing */
  # define __ptrvalue     /* nothing */
  #endif
  
  /*
   * Testing against Clang-specific extensions.
   */
  #ifndef __has_attribute
  #define __has_attribute(x)  0
  #endif
  #ifndef __has_extension
  #define __has_extension     __has_feature
  #endif
  #ifndef __has_feature
  #define __has_feature(x)    0
  #endif
  #ifndef __has_include
  #define __has_include(x)    0
  #endif
  #ifndef __has_builtin
  #define __has_builtin(x)    0
  #endif
  
  #if defined(__cplusplus)
  #define __BEGIN_DECLS   extern "C" {
  #define __END_DECLS }
  #else
  #define __BEGIN_DECLS
  #define __END_DECLS
  #endif
  
  /*
   * This code has been put in place to help reduce the addition of
   * compiler specific defines in FreeBSD code.  It helps to aid in
   * having a compiler-agnostic source tree.
   */
  
  #if defined(__GNUC__) || defined(__INTEL_COMPILER)
  
  #if __GNUC__ >= 3 || defined(__INTEL_COMPILER)
  #define __GNUCLIKE_ASM 3
  #define __GNUCLIKE_MATH_BUILTIN_CONSTANTS
  #else
  #define __GNUCLIKE_ASM 2
  #endif
  #define __GNUCLIKE___TYPEOF 1
  #define __GNUCLIKE___OFFSETOF 1
  #define __GNUCLIKE___SECTION 1
  
  #ifndef __INTEL_COMPILER
  #define __GNUCLIKE_CTOR_SECTION_HANDLING 1
  #endif
  
  #define __GNUCLIKE_BUILTIN_CONSTANT_P 1
  #if defined(__INTEL_COMPILER) && defined(__cplusplus) && \
     __INTEL_COMPILER < 800
  #undef __GNUCLIKE_BUILTIN_CONSTANT_P
  #endif
  
  #if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3)
  #define __GNUCLIKE_BUILTIN_VARARGS 1
  #define __GNUCLIKE_BUILTIN_STDARG 1
  #define __GNUCLIKE_BUILTIN_VAALIST 1
  #endif
  
  #if defined(__GNUC__)
  #define __GNUC_VA_LIST_COMPATIBILITY 1
  #endif
  
  /*
   * Compiler memory barriers, specific to gcc and clang.
   */
  #if defined(__GNUC__)
  #define __compiler_membar() __asm __volatile(" " : : : "memory")
  #endif
  
  #ifndef __INTEL_COMPILER
  #define __GNUCLIKE_BUILTIN_NEXT_ARG 1
  #define __GNUCLIKE_MATH_BUILTIN_RELOPS
  #endif
  
  #define __GNUCLIKE_BUILTIN_MEMCPY 1
  
  /* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */
  #define __CC_SUPPORTS_INLINE 1
  #define __CC_SUPPORTS___INLINE 1
  #define __CC_SUPPORTS___INLINE__ 1
  
  #define __CC_SUPPORTS___FUNC__ 1
  #define __CC_SUPPORTS_WARNING 1
  
  #define __CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */
  
  #define __CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1
  
  #endif /* __GNUC__ || __INTEL_COMPILER */
  
  /*
   * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
   * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
   * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
   * mode -- there must be no spaces between its arguments, and for nested
   * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
   * concatenate double-quoted strings produced by the __STRING macro, but
   * this only works with ANSI C.
   *
   * __XSTRING is like __STRING, but it expands any macros in its argument
   * first.  It is only available with ANSI C.
   */
  #if defined(__STDC__) || defined(__cplusplus)
  #define __P(protos) protos      /* full-blown ANSI C */
  #define __CONCAT1(x,y)  x ## y
  #define __CONCAT(x,y)   __CONCAT1(x,y)
  #define __STRING(x) #x      /* stringify without expanding x */
  #define __XSTRING(x)    __STRING(x) /* expand x, then stringify */
  
  #define __const     const       /* define reserved names to standard */
  #define __signed    signed
  #define __volatile  volatile
  #if defined(__cplusplus)
  #define __inline    inline      /* convert to C++ keyword */
  #else
  #if !(defined(__CC_SUPPORTS___INLINE))
  #define __inline            /* delete GCC keyword */
  #endif /* ! __CC_SUPPORTS___INLINE */
  #endif /* !__cplusplus */
  
  #else   /* !(__STDC__ || __cplusplus) */
  #define __P(protos) ()      /* traditional C preprocessor */
  #define __CONCAT(x,y)   x/**/y
  #define __STRING(x) "x"
  
  #if !defined(__CC_SUPPORTS___INLINE)
  #define __const             /* delete pseudo-ANSI C keywords */
  #define __inline
  #define __signed
  #define __volatile
  /*
   * In non-ANSI C environments, new programs will want ANSI-only C keywords
   * deleted from the program and old programs will want them left alone.
   * When using a compiler other than gcc, programs using the ANSI C keywords
   * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
   * When using "gcc -traditional", we assume that this is the intent; if
   * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
   */
  #ifndef NO_ANSI_KEYWORDS
  #define const               /* delete ANSI C keywords */
  #define inline
  #define signed
  #define volatile
  #endif  /* !NO_ANSI_KEYWORDS */
  #endif  /* !__CC_SUPPORTS___INLINE */
  #endif  /* !(__STDC__ || __cplusplus) */
  
  /*
   * Compiler-dependent macros to help declare dead (non-returning) and
   * pure (no side effects) functions, and unused variables.  They are
   * null except for versions of gcc that are known to support the features
   * properly (old versions of gcc-2 supported the dead and pure features
   * in a different (wrong) way).  If we do not provide an implementation
   * for a given compiler, let the compile fail if it is told to use
   * a feature that we cannot live without.
   */
  #ifdef lint
  #define __dead2
  #define __pure2
  #define __unused
  #define __packed
  #define __aligned(x)
  #define __alloc_align(x)
  #define __alloc_size(x)
  #define __section(x)
  #define __weak_symbol
  #else
  #define __weak_symbol   __attribute__((__weak__))
  #if !__GNUC_PREREQ__(2, 5) && !defined(__INTEL_COMPILER)
  #define __dead2
  #define __pure2
  #define __unused
  #endif
  #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7 && !defined(__INTEL_COMPILER)
  #define __dead2     __attribute__((__noreturn__))
  #define __pure2     __attribute__((__const__))
  #define __unused
  /* XXX Find out what to do for __packed, __aligned and __section */
  #endif
  #if __GNUC_PREREQ__(2, 7) || defined(__INTEL_COMPILER)
  #define __dead2     __attribute__((__noreturn__))
  #define __pure2     __attribute__((__const__))
  #define __unused    __attribute__((__unused__))
  #define __used      __attribute__((__used__))
  #define __packed    __attribute__((__packed__))
  #define __aligned(x)    __attribute__((__aligned__(x)))
  #define __section(x)    __attribute__((__section__(x)))
  #endif
  #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__)
  #define __alloc_size(x) __attribute__((__alloc_size__(x)))
  #else
  #define __alloc_size(x)
  #endif
  #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__)
  #define __alloc_align(x)    __attribute__((__alloc_align__(x)))
  #else
  #define __alloc_align(x)
  #endif
  #endif /* lint */
  
  #if !__GNUC_PREREQ__(2, 95)
  #define __alignof(x)    __offsetof(struct { char __a; x __b; }, __b)
  #endif
  
  /*
   * Keywords added in C11.
   */
  
  #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L || defined(lint)
  
  #if !__has_extension(c_alignas)
  #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
      __has_extension(cxx_alignas)
  #define _Alignas(x)     alignas(x)
  #else
  /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */
  #define _Alignas(x)     __aligned(x)
  #endif
  #endif
  
  #if defined(__cplusplus) && __cplusplus >= 201103L
  #define _Alignof(x)     alignof(x)
  #else
  #define _Alignof(x)     __alignof(x)
  #endif
  
  #if !__has_extension(c_atomic) && !__has_extension(cxx_atomic)
  /*
   * No native support for _Atomic(). Place object in structure to prevent
   * most forms of direct non-atomic access.
   */
  #define _Atomic(T)      struct { T volatile __val; }
  #endif
  
  #if defined(__cplusplus) && __cplusplus >= 201103L
  #define _Noreturn       [[noreturn]]
  #else
  #define _Noreturn       __dead2
  #endif
  
  #if !__has_extension(c_static_assert)
  #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
      __has_extension(cxx_static_assert)
  #define _Static_assert(x, y)    static_assert(x, y)
  #elif __GNUC_PREREQ__(4,6)
  /* Nothing, gcc 4.6 and higher has _Static_assert built-in */
  #elif defined(__COUNTER__)
  #define _Static_assert(x, y)    __Static_assert(x, __COUNTER__)
  #define __Static_assert(x, y)   ___Static_assert(x, y)
  #define ___Static_assert(x, y)  typedef char __assert_ ## y[(x) ? 1 : -1] \
                  __unused
  #else
  #define _Static_assert(x, y)    struct __hack
  #endif
  #endif
  
  #if !__has_extension(c_thread_local)
  /*
   * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode
   * without actually supporting the thread_local keyword. Don't check for
   * the presence of C++11 when defining _Thread_local.
   */
  #if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \
      __has_extension(cxx_thread_local)
  #define _Thread_local       thread_local
  #else
  #define _Thread_local       __thread
  #endif
  #endif
  
  #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
  
  /*
   * Emulation of C11 _Generic().  Unlike the previously defined C11
   * keywords, it is not possible to implement this using exactly the same
   * syntax.  Therefore implement something similar under the name
   * __generic().  Unlike _Generic(), this macro can only distinguish
   * between a single type, so it requires nested invocations to
   * distinguish multiple cases.
   */
  
  #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
      __has_extension(c_generic_selections)
  #define __generic(expr, t, yes, no)                 \
      _Generic(expr, t: yes, default: no)
  #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
  #define __generic(expr, t, yes, no)                 \
      __builtin_choose_expr(                      \
          __builtin_types_compatible_p(__typeof(expr), t), yes, no)
  #endif
  
  #if __GNUC_PREREQ__(2, 96)
  #define __malloc_like   __attribute__((__malloc__))
  #define __pure      __attribute__((__pure__))
  #else
  #define __malloc_like
  #define __pure
  #endif
  
  #if __GNUC_PREREQ__(3, 1) || (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 800)
  #define __always_inline __attribute__((__always_inline__))
  #else
  #define __always_inline
  #endif
  
  #if __GNUC_PREREQ__(3, 1)
  #define __noinline  __attribute__ ((__noinline__))
  #else
  #define __noinline
  #endif
  
  #if __GNUC_PREREQ__(3, 3)
  #define __nonnull(x)    __attribute__((__nonnull__(x)))
  #define __nonnull_all   __attribute__((__nonnull__))
  #else
  #define __nonnull(x)
  #define __nonnull_all
  #endif
  
  #if __GNUC_PREREQ__(3, 4)
  #define __fastcall  __attribute__((__fastcall__))
  #define __result_use_check  __attribute__((__warn_unused_result__))
  #else
  #define __fastcall
  #define __result_use_check
  #endif
  
  #if __GNUC_PREREQ__(4, 1)
  #define __returns_twice __attribute__((__returns_twice__))
  #else
  #define __returns_twice
  #endif
  
  #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable)
  #define __unreachable() __builtin_unreachable()
  #else
  #define __unreachable() ((void)0)
  #endif
  
  /* XXX: should use `#if __STDC_VERSION__ < 199901'. */
  #if !__GNUC_PREREQ__(2, 7) && !defined(__INTEL_COMPILER)
  #define __func__    NULL
  #endif
  
  /*
   * GCC 2.95 provides `__restrict' as an extension to C90 to support the
   * C99-specific `restrict' type qualifier.  We happen to use `__restrict' as
   * a way to define the `restrict' type qualifier without disturbing older
   * software that is unaware of C99 keywords.
   */
  #if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
  #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901 || defined(lint)
  #define __restrict
  #else
  #define __restrict  restrict
  #endif
  #endif
  
  /*
   * GNU C version 2.96 adds explicit branch prediction so that
   * the CPU back-end can hint the processor and also so that
   * code blocks can be reordered such that the predicted path
   * sees a more linear flow, thus improving cache behavior, etc.
   *
   * The following two macros provide us with a way to utilize this
   * compiler feature.  Use __predict_true() if you expect the expression
   * to evaluate to true, and __predict_false() if you expect the
   * expression to evaluate to false.
   *
   * A few notes about usage:
   *
   *  * Generally, __predict_false() error condition checks (unless
   *    you have some _strong_ reason to do otherwise, in which case
   *    document it), and/or __predict_true() `no-error' condition
   *    checks, assuming you want to optimize for the no-error case.
   *
   *  * Other than that, if you don't know the likelihood of a test
   *    succeeding from empirical or other `hard' evidence, don't
   *    make predictions.
   *
   *  * These are meant to be used in places that are run `a lot'.
   *    It is wasteful to make predictions in code that is run
   *    seldomly (e.g. at subsystem initialization time) as the
   *    basic block reordering that this affects can often generate
   *    larger code.
   */
  #if __GNUC_PREREQ__(2, 96)
  #define __predict_true(exp)     __builtin_expect((exp), 1)
  #define __predict_false(exp)    __builtin_expect((exp), 0)
  #else
  #define __predict_true(exp)     (exp)
  #define __predict_false(exp)    (exp)
  #endif
  
  #if __GNUC_PREREQ__(4, 0)
  #define __sentinel  __attribute__((__sentinel__))
  #define __exported  __attribute__((__visibility__("default")))
  #define __hidden    __attribute__((__visibility__("hidden")))
  #else
  #define __sentinel
  #define __exported
  #define __hidden
  #endif
  
  #define __offsetof(type, field) offsetof(type, field)
  #define __rangeof(type, start, end) \
      (__offsetof(type, end) - __offsetof(type, start))
  
  /*
   * Given the pointer x to the member m of the struct s, return
   * a pointer to the containing structure.  When using GCC, we first
   * assign pointer x to a local variable, to check that its type is
   * compatible with member m.
   */
  #if __GNUC_PREREQ__(3, 1)
  #define __containerof(x, s, m) ({                   \
      const volatile __typeof(((s *)0)->m) *__x = (x);        \
      __DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\
  })
  #else
  #define __containerof(x, s, m)                      \
      __DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m))
  #endif
  
  /*
   * Compiler-dependent macros to declare that functions take printf-like
   * or scanf-like arguments.  They are null except for versions of gcc
   * that are known to support the features properly (old versions of gcc-2
   * didn't permit keeping the keywords out of the application namespace).
   */
  #if !__GNUC_PREREQ__(2, 7) && !defined(__INTEL_COMPILER)
  #define __printflike(fmtarg, firstvararg)
  #define __scanflike(fmtarg, firstvararg)
  #define __format_arg(fmtarg)
  #define __strfmonlike(fmtarg, firstvararg)
  #define __strftimelike(fmtarg, firstvararg)
  #else
  #define __printflike(fmtarg, firstvararg) \
          __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
  #define __scanflike(fmtarg, firstvararg) \
          __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
  #define __format_arg(fmtarg)    __attribute__((__format_arg__ (fmtarg)))
  #define __strfmonlike(fmtarg, firstvararg) \
          __attribute__((__format__ (__strfmon__, fmtarg, firstvararg)))
  #define __strftimelike(fmtarg, firstvararg) \
          __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
  #endif
  
  /*
   * FORTIFY_SOURCE, and perhaps other compiler-specific features, require
   * the use of non-standard inlining.  In general we should try to avoid
   * using these but GCC-compatible compilers tend to support the extensions
   * well enough to use them in limited cases.
   */
  #if defined(__GNUC_GNU_INLINE__) || defined(__GNUC_STDC_INLINE__)
  #if __GNUC_PREREQ__(4, 3) || __has_attribute(__artificial__)
  #define __gnu_inline    __attribute__((__gnu_inline__, __artificial__))
  #else
  #define __gnu_inline    __attribute__((__gnu_inline__))
  #endif /* artificial */
  #else
  #define __gnu_inline
  #endif
  
  /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
  #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
      defined(__GNUC__) && !defined(__INTEL_COMPILER)
  #define __printf0like(fmtarg, firstvararg) \
          __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
  #else
  #define __printf0like(fmtarg, firstvararg)
  #endif
  
  #if defined(__GNUC__) || defined(__INTEL_COMPILER)
  #ifndef __INTEL_COMPILER
  #define __strong_reference(sym,aliassym)    \
      extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
  #endif
  #ifdef __ELF__
  #ifdef __STDC__
  #define __weak_reference(sym,alias) \
      __asm__(".weak " #alias);   \
      __asm__(".equ "  #alias ", " #sym)
  #define __warn_references(sym,msg)  \
      __asm__(".section .gnu.warning." #sym); \
      __asm__(".asciz \"" msg "\"");  \
      __asm__(".previous")
  #define __sym_compat(sym,impl,verid)    \
      __asm__(".symver " #impl ", " #sym "@" #verid)
  #define __sym_default(sym,impl,verid)   \
      __asm__(".symver " #impl ", " #sym "@@" #verid)
  #else
  #define __weak_reference(sym,alias) \
      __asm__(".weak alias");     \
      __asm__(".equ alias, sym")
  #define __warn_references(sym,msg)  \
      __asm__(".section .gnu.warning.sym"); \
      __asm__(".asciz \"msg\"");  \
      __asm__(".previous")
  #define __sym_compat(sym,impl,verid)    \
      __asm__(".symver impl, sym@verid")
  #define __sym_default(impl,sym,verid)   \
      __asm__(".symver impl, sym@@verid")
  #endif  /* __STDC__ */
  #else   /* !__ELF__ */
  #ifdef __STDC__
  #define __weak_reference(sym,alias) \
      __asm__(".stabs \"_" #alias "\",11,0,0,0"); \
      __asm__(".stabs \"_" #sym "\",1,0,0,0")
  #define __warn_references(sym,msg)  \
      __asm__(".stabs \"" msg "\",30,0,0,0");     \
      __asm__(".stabs \"_" #sym "\",1,0,0,0")
  #else
  #define __weak_reference(sym,alias) \
      __asm__(".stabs \"_/**/alias\",11,0,0,0");  \
      __asm__(".stabs \"_/**/sym\",1,0,0,0")
  #define __warn_references(sym,msg)  \
      __asm__(".stabs msg,30,0,0,0");         \
      __asm__(".stabs \"_/**/sym\",1,0,0,0")
  #endif  /* __STDC__ */
  #endif  /* __ELF__ */
  #endif  /* __GNUC__ || __INTEL_COMPILER */
  
  #ifndef __FBSDID
  #define __FBSDID(s) struct __hack
  #endif
  
  #ifndef __RCSID
  #define __RCSID(s)  struct __hack
  #endif
  
  #ifndef __RCSID_SOURCE
  #define __RCSID_SOURCE(s)   struct __hack
  #endif
  
  #ifndef __SCCSID
  #define __SCCSID(s) struct __hack
  #endif
  
  #ifndef __COPYRIGHT
  #define __COPYRIGHT(s)  struct __hack
  #endif
  
  #ifndef __DECONST
  #define __DECONST(type, var)    ((type)(__uintptr_t)(const void *)(var))
  #endif
  
  #ifndef __DEVOLATILE
  #define __DEVOLATILE(type, var) ((type)(__uintptr_t)(volatile void *)(var))
  #endif
  
  #ifndef __DEQUALIFY
  #define __DEQUALIFY(type, var)  ((type)(__uintptr_t)(const volatile void *)(var))
  #endif
  
  /*
   * Type Safety Checking
   *
   * Clang provides additional attributes to enable checking type safety
   * properties that cannot be enforced by the C type system.
   */
  
  #if __has_attribute(__argument_with_type_tag__) && \
      __has_attribute(__type_tag_for_datatype__) && !defined(lint)
  #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) \
          __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx)))
  #define __datatype_type_tag(kind, type) \
          __attribute__((__type_tag_for_datatype__(kind, type)))
  #else
  #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx)
  #define __datatype_type_tag(kind, type)
  #endif
  
  /*
   * Lock annotations.
   *
   * Clang provides support for doing basic thread-safety tests at
   * compile-time, by marking which locks will/should be held when
   * entering/leaving a functions.
   *
   * Furthermore, it is also possible to annotate variables and structure
   * members to enforce that they are only accessed when certain locks are
   * held.
   */
  
  #if __has_extension(c_thread_safety_attributes)
  #define __lock_annotate(x)  __attribute__((x))
  #else
  #define __lock_annotate(x)
  #endif
  
  /* Structure implements a lock. */
  #define __lockable      __lock_annotate(lockable)
  
  /* Function acquires an exclusive or shared lock. */
  #define __locks_exclusive(...) \
      __lock_annotate(exclusive_lock_function(__VA_ARGS__))
  #define __locks_shared(...) \
      __lock_annotate(shared_lock_function(__VA_ARGS__))
  
  /* Function attempts to acquire an exclusive or shared lock. */
  #define __trylocks_exclusive(...) \
      __lock_annotate(exclusive_trylock_function(__VA_ARGS__))
  #define __trylocks_shared(...) \
      __lock_annotate(shared_trylock_function(__VA_ARGS__))
  
  /* Function releases a lock. */
  #define __unlocks(...)      __lock_annotate(unlock_function(__VA_ARGS__))
  
  /* Function asserts that an exclusive or shared lock is held. */
  #define __asserts_exclusive(...) \
      __lock_annotate(assert_exclusive_lock(__VA_ARGS__))
  #define __asserts_shared(...) \
      __lock_annotate(assert_shared_lock(__VA_ARGS__))
  
  /* Function requires that an exclusive or shared lock is or is not held. */
  #define __requires_exclusive(...) \
      __lock_annotate(exclusive_locks_required(__VA_ARGS__))
  #define __requires_shared(...) \
      __lock_annotate(shared_locks_required(__VA_ARGS__))
  #define __requires_unlocked(...) \
      __lock_annotate(locks_excluded(__VA_ARGS__))
  
  /* Function should not be analyzed. */
  #define __no_lock_analysis  __lock_annotate(no_thread_safety_analysis)
  
  /* Guard variables and structure members by lock. */
  #define __guarded_by(x)     __lock_annotate(guarded_by(x))
  #define __pt_guarded_by(x)  __lock_annotate(pt_guarded_by(x))
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* SYS_CDEFS_H */