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Edit File : ruby.h \| Size : 14.74 KB
#ifndef RUBY_RUBY_H /--C++--vi:se ft=cpp:/ #define RUBY_RUBY_H 1 /** * @file * @author $Author$ * @date Thu Jun 10 14:26:32 JST 1993 * @copyright Copyright (C) 1993-2008 Yukihiro Matsumoto * @copyright Copyright (C) 2000 Network Applied Communication Laboratory, Inc. * @copyright Copyright (C) 2000 Information-technology Promotion Agency, Japan * @copyright This file is a part of the programming language Ruby. * Permission is hereby granted, to either redistribute and/or * modify this file, provided that the conditions mentioned in the * file COPYING are met. Consult the file for details. / #include "ruby/internal/config.h" / @shyouhei doesn't understand why we need <intrinsics.h> at this very * beginning of the entire <ruby.h> circus. / #ifdef HAVE_INTRINSICS_H # include <intrinsics.h> #endif #include <stdarg.h> #include "defines.h" #include "ruby/internal/abi.h" #include "ruby/internal/anyargs.h" #include "ruby/internal/arithmetic.h" #include "ruby/internal/core.h" #include "ruby/internal/ctype.h" #include "ruby/internal/dllexport.h" #include "ruby/internal/error.h" #include "ruby/internal/eval.h" #include "ruby/internal/event.h" #include "ruby/internal/fl_type.h" #include "ruby/internal/gc.h" #include "ruby/internal/glob.h" #include "ruby/internal/globals.h" #include "ruby/internal/has/warning.h" #include "ruby/internal/interpreter.h" #include "ruby/internal/iterator.h" #include "ruby/internal/memory.h" #include "ruby/internal/method.h" #include "ruby/internal/module.h" #include "ruby/internal/newobj.h" #include "ruby/internal/scan_args.h" #include "ruby/internal/special_consts.h" #include "ruby/internal/symbol.h" #include "ruby/internal/value.h" #include "ruby/internal/value_type.h" #include "ruby/internal/variable.h" #include "ruby/assert.h" #include "ruby/backward/2/assume.h" #include "ruby/backward/2/inttypes.h" #include "ruby/backward/2/limits.h" RBIMPL_SYMBOL_EXPORT_BEGIN() / Module#methods, #singleton_methods and so on return Symbols / /* * @private * * @deprecated This macro once was a thing in the old days, but makes no sense * any longer today. Exists here for backwards compatibility * only. You can safely forget about it. / #define USE_SYMBOL_AS_METHOD_NAME 1 /* * Converts an object to a path. It first tries `#to_path` method if any, then * falls back to `#to_str` method. * * @param[in] obj Arbitrary ruby object. * @exception rb_eArgError `obj` contains a NUL byte. * @exception rb_eTypeError `obj` is not path-ish. * @exception rb_eEncCompatError No encoding conversion from `obj` to path. * @return Converted path object. / VALUE rb_get_path(VALUE obj); /* * Ensures that the parameter object is a path. * * @param[in,out] v Arbitrary ruby object. * @exception rb_eArgError `v` contains a NUL byte. * @exception rb_eTypeError `v` is not path-ish. * @exception rb_eEncCompatError `v` is not path-compatible. * @post `v` is a path. / #define FilePathValue(v) (RB_GC_GUARD(v) = rb_get_path(v)) /* * @deprecated This function is an alias of rb_get_path() now. The part that * did "no_checksafe" was deleted. It remains here because of no * harm. / VALUE rb_get_path_no_checksafe(VALUE); /* * This macro actually does the same thing as #FilePathValue now. The "String" * part indicates that this is for when a string is treated like a pathname, * rather than the actual pathname on the file systems. For examples: * `Dir.fnmatch?`, `File.join`, `File.basename`, etc. / #define FilePathStringValue(v) ((v) = rb_get_path(v)) /* @cond INTERNAL_MACRO / #if defined(HAVE_BUILTIN___BUILTIN_CONSTANT_P) && defined(HAVE_STMT_AND_DECL_IN_EXPR) # define rb_varargs_argc_check_runtime(argc, vargc) \ (((argc) <= (vargc)) ? (argc) : \ (rb_fatal("argc(%d) exceeds actual arguments(%d)", \ argc, vargc), 0)) # define rb_varargs_argc_valid_p(argc, vargc) \ ((argc) == 0 ? (vargc) <= 1 : / [ruby-core:85266] [Bug #14425] / \ (argc) == (vargc)) # if defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P) # ifdef HAVE_ATTRIBUTE_ERRORFUNC ERRORFUNC((" argument length doesn't match"), int rb_varargs_bad_length(int,int)); # else # define rb_varargs_bad_length(argc, vargc) \ ((argc)/rb_varargs_argc_valid_p(argc, vargc)) # endif # define rb_varargs_argc_check(argc, vargc) \ __builtin_choose_expr(__builtin_constant_p(argc), \ (rb_varargs_argc_valid_p(argc, vargc) ? (argc) : \ rb_varargs_bad_length(argc, vargc)), \ rb_varargs_argc_check_runtime(argc, vargc)) # else # define rb_varargs_argc_check(argc, vargc) \ rb_varargs_argc_check_runtime(argc, vargc) # endif #endif /* @endcond / /* * Queries the name of the passed class. * * @param[in] klass An instance of a class. * @return The name of `klass`. * @note Return value is managed by our GC. Don't free. / const char rb_class2name(VALUE klass); /** * Queries the name of the class of the passed object. * * @param[in] obj Arbitrary ruby object. * @return The name of the class of `obj`. * @note Return value is managed by our GC. Don't free. / const char rb_obj_classname(VALUE obj); /** * Inspects an object. It first calls the argument's `#inspect` method, then * feeds its result string into ::rb_stdout. * * This is identical to Ruby level `Kernel#p`, except it takes only one object. * * @internal * * Above description is in fact inaccurate. This API interfaces with Ractors. / void rb_p(VALUE obj); /* * This function is an optimised version of calling `#==`. It checks equality * between two objects by first doing a fast identity check using using C's * `==` (same as `BasicObject#equal?`). If that check fails, it calls `#==` * dynamically. This optimisation actually affects semantics, because when * `#==` returns false for the same object obj, `rb_equal(obj, obj)` would * still return true. This happens for `Float::NAN`, where `Float::NAN == * Float::NAN` is `false`, but `rb_equal(Float::NAN, Float::NAN)` is `true`. * * @param[in] lhs Comparison LHS. * @param[in] rhs Comparison RHS. * @retval RUBY_Qtrue They are the same. * @retval RUBY_Qfalse They are different. / VALUE rb_equal(VALUE lhs, VALUE rhs); /* * Identical to rb_require_string(), except it takes C's string instead of * Ruby's. * * @param[in] feature Name of a feature, e.g. `"json"`. * @exception rb_eLoadError No such feature. * @exception rb_eRuntimeError `$"` is frozen; unable to push. * @retval RUBY_Qtrue The feature is loaded for the first time. * @retval RUBY_Qfalse The feature has already been loaded. * @post `$"` is updated. / VALUE rb_require(const char feature); #include "ruby/intern.h" /** * @private * * @deprecated This macro once was a thing in the old days, but makes no sense * any longer today. Exists here for backwards compatibility * only. You can safely forget about it. / #define RUBY_VM 1 / YARV / /* * @private * * @deprecated This macro once was a thing in the old days, but makes no sense * any longer today. Exists here for backwards compatibility * only. You can safely forget about it. / #define HAVE_NATIVETHREAD /* * Queries if the thread which calls this function is a ruby's thread. * "Ruby's" in this context is a thread created using one of our APIs like * rb_thread_create(). There are distinctions between ruby's and other * threads. For instance calling ruby methods are allowed only from inside of * a ruby's thread. * * @retval 1 The current thread is a Ruby's thread. * @retval 0 The current thread is a random thread from outside of Ruby. / int ruby_native_thread_p(void); /* * @private * * This macro is for internal use. Must be a mistake to place here. / #define InitVM(ext) {void InitVM_##ext(void);InitVM_##ext();} RBIMPL_ATTR_NONNULL((3)) RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 3, 4) /* * Our own locale-insensitive version of `snprintf(3)`. It can also be seen as * a routine identical to rb_sprintf(), except it writes back to the passed * buffer instead of allocating a new Ruby object. * * @param[out] str Return buffer * @param[in] n Number of bytes of `str`. * @param[in] fmt A `printf`-like format specifier. * @param[in] ... Variadic number of contents to format. * @return Number of bytes that would have been written to `str`, if `n` * was large enough. Comparing this to `n` can give you insights * that the buffer is too small or too big. Especially passing 0 * to `n` gives you the exact number of bytes necessary to hold * the result string without writing anything to anywhere. * @post `str` holds up to `n-1` bytes of formatted contents (and the * terminating NUL character.) / int ruby_snprintf(char str, size_t n, char const fmt, ...); RBIMPL_ATTR_NONNULL((3)) RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 3, 0) /* * Identical to ruby_snprintf(), except it takes a `va_list`. It can also be * seen as a routine identical to rb_vsprintf(), except it writes back to the * passed buffer instead of allocating a new Ruby object. * * @param[out] str Return buffer * @param[in] n Number of bytes of `str`. * @param[in] fmt A `printf`-like format specifier. * @param[in] ap Contents to format. * @return Number of bytes that would have been written to `str`, if `n` * was large enough. Comparing this to `n` can give you insights * that the buffer is too small or too big. Especially passing 0 * to `n` gives you the exact number of bytes necessary to hold * the result string without writing anything to anywhere. * @post `str` holds up to `n-1` bytes of formatted contents (and the * terminating NUL character.) / int ruby_vsnprintf(char str, size_t n, char const fmt, va_list ap); #include <errno.h> /* * @name Errno handling routines for userland threads * @note POSIX chapter 2 section 3 states that for each thread of a process, * the value of `errno` shall not be affected by function calls or * assignments to `errno` by other threads. * * Soooo this `#define errno` below seems like a noob mistake at first sight. * If you look at its actual implementation, the functions are just adding one * level of indirection. It doesn't make any sense sorry? But yes! @ko1 told * @shyouhei that this is inevitable. * * The ultimate reason is because Ruby now has N:M threads implemented. * Threads of that sort change their context in user land. A function can be * "transferred" between threads in middle of their executions. Let us for * instance consider: * * ```cxx * void foo() * { * auto i = errno; * close(0); * errno = i; * } * ``` * * This function (if ran under our Ractor) could change its running thread at * the `close` function. But the two `errno` invocations are different! Look * how the source code above is compiled by clang 17 with `-O3` flag @ Linux: * * ``` * foo(int): # @foo(int) * push rbp * push r14 * push rbx * mov ebx, edi * call __errno_location@PLT * mov r14, rax * mov ebp, dword ptr [rax] * mov edi, ebx * call close@PLT * mov dword ptr [r14], ebp * pop rbx * pop r14 * pop rbp * ret * ``` * * Notice how `__errno_location@PLT` is `call`-ed only once. The compiler * assumes that the location of `errno` does not change during a function call. * Sadly this is no longer true for us. The `close@PLT` now changes threads, * which should also change where `errno` is stored. * * With the `#define errno` below the compilation result changes to this: * * ``` * foo(int): # @foo(int) * push rbp * push rbx * push rax * mov ebx, edi * call rb_errno_ptr()@PLT * mov ebp, dword ptr [rax] * mov edi, ebx * call close@PLT * call rb_errno_ptr()@PLT * mov dword ptr [rax], ebp * add rsp, 8 * pop rbx * pop rbp * ret * ``` * * Which fixes the problem. / /* * Identical to system `errno`. * * @return The last set `errno` number. / int rb_errno(void); /* * Set the errno. * * @param err New `errno`. * @post `errno` is now set to `err`. / void rb_errno_set(int err); /* * The location of `errno` * * @return The (thread-specific) location of `errno`. / int rb_errno_ptr(void); /** * Not sure if it is necessary for extension libraries but this is where the * "bare" errno is located. * * @return The location of `errno`. / static inline int rb_orig_errno_ptr(void) { return &errno; } #define rb_orig_errno errno /*< System-provided original `errno`. / #undef errno #define errno (rb_errno_ptr()) /< Ractor-aware version of `errno`. / /** @} / /* @cond INTERNAL_MACRO / #if RBIMPL_HAS_WARNING("-Wgnu-zero-variadic-macro-arguments") # / Skip it; clang -pedantic doesn't like the following / #elif defined(__GNUC__) && defined(HAVE_VA_ARGS_MACRO) && defined(__OPTIMIZE__) # define rb_yield_values(argc, ...) \ __extension__({ \ const int rb_yield_values_argc = (argc); \ const VALUE rb_yield_values_args[] = {__VA_ARGS__}; \ const int rb_yield_values_nargs = \ (int)(sizeof(rb_yield_values_args) / sizeof(VALUE)); \ rb_yield_values2( \ rb_varargs_argc_check(rb_yield_values_argc, rb_yield_values_nargs), \ rb_yield_values_nargs ? rb_yield_values_args : NULL); \ }) # define rb_funcall(recv, mid, argc, ...) \ __extension__({ \ const int rb_funcall_argc = (argc); \ const VALUE rb_funcall_args[] = {__VA_ARGS__}; \ const int rb_funcall_nargs = \ (int)(sizeof(rb_funcall_args) / sizeof(VALUE)); \ rb_funcallv(recv, mid, \ rb_varargs_argc_check(rb_funcall_argc, rb_funcall_nargs), \ rb_funcall_nargs ? rb_funcall_args : NULL); \ }) #endif /* @endcond / #ifndef RUBY_DONT_SUBST #include "ruby/subst.h" #endif #if !defined RUBY_EXPORT && !defined RUBY_NO_OLD_COMPATIBILITY # include "ruby/backward.h" #endif RBIMPL_SYMBOL_EXPORT_END() #endif / RUBY_RUBY_H */ Back

Edit File : ruby.h | Size : 14.74 KB

#ifndef RUBY_RUBY_H                                  /*-*-C++-*-vi:se ft=cpp:*/
#define RUBY_RUBY_H 1
/**
 * @file
 * @author     $Author$
 * @date       Thu Jun 10 14:26:32 JST 1993
 * @copyright  Copyright (C) 1993-2008 Yukihiro Matsumoto
 * @copyright  Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
 * @copyright  Copyright (C) 2000  Information-technology Promotion Agency, Japan
 * @copyright  This  file  is   a  part  of  the   programming  language  Ruby.
 *             Permission  is hereby  granted,  to  either redistribute  and/or
 *             modify this file, provided that  the conditions mentioned in the
 *             file COPYING are met.  Consult the file for details.
 */
#include "ruby/internal/config.h"

/* @shyouhei  doesn't  understand  why  we need  <intrinsics.h>  at  this  very
 * beginning of the entire <ruby.h> circus. */
#ifdef HAVE_INTRINSICS_H
# include <intrinsics.h>
#endif

#include <stdarg.h>

#include "defines.h"
#include "ruby/internal/abi.h"
#include "ruby/internal/anyargs.h"
#include "ruby/internal/arithmetic.h"
#include "ruby/internal/core.h"
#include "ruby/internal/ctype.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/error.h"
#include "ruby/internal/eval.h"
#include "ruby/internal/event.h"
#include "ruby/internal/fl_type.h"
#include "ruby/internal/gc.h"
#include "ruby/internal/glob.h"
#include "ruby/internal/globals.h"
#include "ruby/internal/has/warning.h"
#include "ruby/internal/interpreter.h"
#include "ruby/internal/iterator.h"
#include "ruby/internal/memory.h"
#include "ruby/internal/method.h"
#include "ruby/internal/module.h"
#include "ruby/internal/newobj.h"
#include "ruby/internal/scan_args.h"
#include "ruby/internal/special_consts.h"
#include "ruby/internal/symbol.h"
#include "ruby/internal/value.h"
#include "ruby/internal/value_type.h"
#include "ruby/internal/variable.h"
#include "ruby/assert.h"
#include "ruby/backward/2/assume.h"
#include "ruby/backward/2/inttypes.h"
#include "ruby/backward/2/limits.h"

RBIMPL_SYMBOL_EXPORT_BEGIN()

/* Module#methods, #singleton_methods and so on return Symbols */
/**
 * @private
 *
 * @deprecated  This macro once was a thing in the old days, but makes no sense
 *              any  longer today.   Exists  here  for backwards  compatibility
 *              only.  You can safely forget about it.
 */
#define USE_SYMBOL_AS_METHOD_NAME 1

/**
 * Converts an object to a path.  It first tries `#to_path` method if any, then
 * falls back to `#to_str` method.
 *
 * @param[in]  obj                 Arbitrary ruby object.
 * @exception  rb_eArgError        `obj` contains a NUL byte.
 * @exception  rb_eTypeError       `obj` is not path-ish.
 * @exception  rb_eEncCompatError  No encoding conversion from `obj` to path.
 * @return     Converted path object.
 */
VALUE rb_get_path(VALUE obj);

/**
 * Ensures that the parameter object is a path.
 *
 * @param[in,out]  v                   Arbitrary ruby object.
 * @exception      rb_eArgError        `v` contains a NUL byte.
 * @exception      rb_eTypeError       `v` is not path-ish.
 * @exception      rb_eEncCompatError  `v` is not path-compatible.
 * @post           `v` is a path.
 */
#define FilePathValue(v) (RB_GC_GUARD(v) = rb_get_path(v))

/**
 * @deprecated  This function is an alias  of rb_get_path() now.  The part that
 *              did "no_checksafe" was deleted.  It  remains here because of no
 *              harm.
 */
VALUE rb_get_path_no_checksafe(VALUE);

/**
 * This macro actually does the same  thing as #FilePathValue now.  The "String"
 * part indicates  that this is  for when a string  is treated like  a pathname,
 * rather  than  the  actual  pathname  on  the  file  systems.   For  examples:
 * `Dir.fnmatch?`, `File.join`, `File.basename`, etc.
 */
#define FilePathStringValue(v) ((v) = rb_get_path(v))

/** @cond INTERNAL_MACRO */
#if defined(HAVE_BUILTIN___BUILTIN_CONSTANT_P) && defined(HAVE_STMT_AND_DECL_IN_EXPR)
# define rb_varargs_argc_check_runtime(argc, vargc) \
    (((argc) <= (vargc)) ? (argc) : \
     (rb_fatal("argc(%d) exceeds actual arguments(%d)", \
               argc, vargc), 0))
# define rb_varargs_argc_valid_p(argc, vargc) \
    ((argc) == 0 ? (vargc) <= 1 : /* [ruby-core:85266] [Bug #14425] */ \
     (argc) == (vargc))
# if defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P)
#   ifdef HAVE_ATTRIBUTE_ERRORFUNC
ERRORFUNC((" argument length doesn't match"), int rb_varargs_bad_length(int,int));
#   else
#     define rb_varargs_bad_length(argc, vargc) \
        ((argc)/rb_varargs_argc_valid_p(argc, vargc))
#   endif
#   define rb_varargs_argc_check(argc, vargc) \
    __builtin_choose_expr(__builtin_constant_p(argc), \
        (rb_varargs_argc_valid_p(argc, vargc) ? (argc) : \
         rb_varargs_bad_length(argc, vargc)), \
        rb_varargs_argc_check_runtime(argc, vargc))
# else
#   define rb_varargs_argc_check(argc, vargc) \
        rb_varargs_argc_check_runtime(argc, vargc)
# endif
#endif
/** @endcond */

/**
 * Queries the name of the passed class.
 *
 * @param[in]  klass  An instance of a class.
 * @return     The name of `klass`.
 * @note       Return value is managed by our GC.  Don't free.
 */
const char *rb_class2name(VALUE klass);

/**
 * Queries the name of the class of the passed object.
 *
 * @param[in]  obj  Arbitrary ruby object.
 * @return     The name of the class of `obj`.
 * @note       Return value is managed by our GC.  Don't free.
 */
const char *rb_obj_classname(VALUE obj);

/**
 * Inspects an object.   It first calls the argument's  `#inspect` method, then
 * feeds its result string into ::rb_stdout.
 *
 * This is identical to Ruby level `Kernel#p`, except it takes only one object.
 *
 * @internal
 *
 * Above description is in fact inaccurate.  This API interfaces with Ractors.
 */
void rb_p(VALUE obj);

/**
 * This function is an optimised version  of calling `#==`.  It checks equality
 * between two  objects by first  doing a fast  identity check using  using C's
 * `==` (same  as `BasicObject#equal?`).  If  that check fails, it  calls `#==`
 * dynamically.   This optimisation  actually affects  semantics, because  when
 * `#==`  returns false  for the  same object  obj, `rb_equal(obj,  obj)` would
 * still  return true.   This happens  for `Float::NAN`,  where `Float::NAN  ==
 * Float::NAN` is `false`, but `rb_equal(Float::NAN, Float::NAN)` is `true`.
 *
 * @param[in]  lhs          Comparison LHS.
 * @param[in]  rhs          Comparison RHS.
 * @retval     RUBY_Qtrue   They are the same.
 * @retval     RUBY_Qfalse  They are different.
 */
VALUE rb_equal(VALUE lhs, VALUE rhs);

/**
 * Identical  to rb_require_string(),  except it  takes C's  string instead  of
 * Ruby's.
 *
 * @param[in]  feature           Name of a feature, e.g. `"json"`.
 * @exception  rb_eLoadError     No such feature.
 * @exception  rb_eRuntimeError  `$"` is frozen; unable to push.
 * @retval     RUBY_Qtrue        The feature is loaded for the first time.
 * @retval     RUBY_Qfalse       The feature has already been loaded.
 * @post       `$"` is updated.
 */
VALUE rb_require(const char *feature);

#include "ruby/intern.h"

/**
 * @private
 *
 * @deprecated  This macro once was a thing in the old days, but makes no sense
 *              any  longer today.   Exists  here  for backwards  compatibility
 *              only.  You can safely forget about it.
 */
#define RUBY_VM 1 /* YARV */

/**
 * Queries  if  the thread  which  calls  this  function  is a  ruby's  thread.
 * "Ruby's" in  this context  is a thread  created using one  of our  APIs like
 * rb_thread_create().   There  are  distinctions   between  ruby's  and  other
 * threads.  For instance calling ruby methods  are allowed only from inside of
 * a ruby's thread.
 *
 * @retval  1  The current thread is a Ruby's thread.
 * @retval  0  The current thread is a random thread from outside of Ruby.
 */
int ruby_native_thread_p(void);

/**
 * @private
 *
 * This macro is for internal use.  Must be a mistake to place here.
 */
#define InitVM(ext) {void InitVM_##ext(void);InitVM_##ext();}

RBIMPL_ATTR_NONNULL((3))
RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 3, 4)
/**
 * Our own locale-insensitive version of `snprintf(3)`.  It can also be seen as
 * a routine  identical to rb_sprintf(),  except it  writes back to  the passed
 * buffer instead of allocating a new Ruby object.
 *
 * @param[out]  str  Return buffer
 * @param[in]   n    Number of bytes of `str`.
 * @param[in]   fmt  A `printf`-like format specifier.
 * @param[in]   ...  Variadic number of contents to format.
 * @return      Number of bytes  that would have been written to  `str`, if `n`
 *              was large enough.  Comparing this  to `n` can give you insights
 *              that the buffer is too small  or too big.  Especially passing 0
 *              to `n`  gives you the exact  number of bytes necessary  to hold
 *              the result string without writing anything to anywhere.
 * @post        `str` holds  up to `n-1`  bytes of formatted contents  (and the
 *              terminating NUL character.)
 */
int ruby_snprintf(char *str, size_t n, char const *fmt, ...);

RBIMPL_ATTR_NONNULL((3))
RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 3, 0)
/**
 * Identical to ruby_snprintf(),  except it takes a `va_list`.  It  can also be
 * seen as a  routine identical to rb_vsprintf(), except it  writes back to the
 * passed buffer instead of allocating a new Ruby object.
 *
 * @param[out]  str  Return buffer
 * @param[in]   n    Number of bytes of `str`.
 * @param[in]   fmt  A `printf`-like format specifier.
 * @param[in]   ap   Contents  to format.
 * @return      Number of bytes  that would have been written to  `str`, if `n`
 *              was large enough.  Comparing this  to `n` can give you insights
 *              that the buffer is too small  or too big.  Especially passing 0
 *              to `n`  gives you the exact  number of bytes necessary  to hold
 *              the result string without writing anything to anywhere.
 * @post        `str` holds  up to `n-1`  bytes of formatted contents  (and the
 *              terminating NUL character.)
 */
int ruby_vsnprintf(char *str, size_t n, char const *fmt, va_list ap);

#include <errno.h>

/**
 * @name  Errno handling routines for userland threads
 * @note  POSIX chapter 2 section 3 states  that for each thread  of a process,
 *        the  value of  `errno` shall  not be  affected by  function calls  or
 *        assignments to `errno` by other threads.
 *
 * Soooo this `#define  errno` below seems like a noob  mistake at first sight.
 * If you look at its actual  implementation, the functions are just adding one
 * level of indirection.  It doesn't make any sense sorry?  But yes!  @ko1 told
 * @shyouhei that this is inevitable.
 *
 * The  ultimate  reason is  because  Ruby  now  has N:M  threads  implemented.
 * Threads of that sort  change their context in user land.   A function can be
 * "transferred" between  threads in  middle of their  executions.  Let  us for
 * instance consider:
 *
 * ```cxx
 * void foo()
 * {
 *     auto i = errno;
 *     close(0);
 *     errno = i;
 * }
 * ```
 *
 * This function (if  ran under our Ractor) could change  its running thread at
 * the `close` function.  But the  two `errno` invocations are different!  Look
 * how the source code above is compiled by clang 17 with `-O3` flag @ Linux:
 *
 * ```
 * foo(int):                                # @foo(int)
 *         push    rbp
 *         push    r14
 *         push    rbx
 *         mov     ebx, edi
 *         call    __errno_location@PLT
 *         mov     r14, rax
 *         mov     ebp, dword ptr [rax]
 *         mov     edi, ebx
 *         call    close@PLT
 *         mov     dword ptr [r14], ebp
 *         pop     rbx
 *         pop     r14
 *         pop     rbp
 *         ret
 * ```
 *
 * Notice  how `__errno_location@PLT`  is  `call`-ed only  once.  The  compiler
 * assumes that the location of `errno` does not change during a function call.
 * Sadly this is  no longer true for us.  The  `close@PLT` now changes threads,
 * which should also change where `errno` is stored.
 *
 * With the `#define errno` below the compilation result changes to this:
 *
 * ```
 * foo(int):                                # @foo(int)
 *         push    rbp
 *         push    rbx
 *         push    rax
 *         mov     ebx, edi
 *         call    rb_errno_ptr()@PLT
 *         mov     ebp, dword ptr [rax]
 *         mov     edi, ebx
 *         call    close@PLT
 *         call    rb_errno_ptr()@PLT
 *         mov     dword ptr [rax], ebp
 *         add     rsp, 8
 *         pop     rbx
 *         pop     rbp
 *         ret
 * ```
 *
 * Which fixes the problem.
 */

/**
 * Identical to system `errno`.
 *
 * @return The last set `errno` number.
 */
int rb_errno(void);

/**
 * Set the errno.
 *
 * @param  err  New `errno`.
 * @post   `errno` is now set to `err`.
 */
void rb_errno_set(int err);

/**
 * The location of `errno`
 *
 * @return The (thread-specific) location of `errno`.
 */
int *rb_errno_ptr(void);

/**
 * Not sure if  it is necessary for  extension libraries but this  is where the
 * "bare" errno is located.
 *
 * @return The location of `errno`.
 */
static inline int *
rb_orig_errno_ptr(void)
{
    return &errno;
}

#define rb_orig_errno errno /**< System-provided original `errno`. */
#undef errno
#define errno (*rb_errno_ptr()) /**< Ractor-aware version of `errno`. */

/** @} */

/** @cond INTERNAL_MACRO */
#if RBIMPL_HAS_WARNING("-Wgnu-zero-variadic-macro-arguments")
# /* Skip it; clang -pedantic doesn't like the following */
#elif defined(__GNUC__) && defined(HAVE_VA_ARGS_MACRO) && defined(__OPTIMIZE__)
# define rb_yield_values(argc, ...) \
__extension__({ \
        const int rb_yield_values_argc = (argc); \
        const VALUE rb_yield_values_args[] = {__VA_ARGS__}; \
        const int rb_yield_values_nargs = \
            (int)(sizeof(rb_yield_values_args) / sizeof(VALUE)); \
        rb_yield_values2( \
            rb_varargs_argc_check(rb_yield_values_argc, rb_yield_values_nargs), \
            rb_yield_values_nargs ? rb_yield_values_args : NULL); \
    })

# define rb_funcall(recv, mid, argc, ...) \
__extension__({ \
        const int rb_funcall_argc = (argc); \
        const VALUE rb_funcall_args[] = {__VA_ARGS__}; \
        const int rb_funcall_nargs = \
            (int)(sizeof(rb_funcall_args) / sizeof(VALUE)); \
        rb_funcallv(recv, mid, \
            rb_varargs_argc_check(rb_funcall_argc, rb_funcall_nargs), \
            rb_funcall_nargs ? rb_funcall_args : NULL); \
    })
#endif
/** @endcond */

#ifndef RUBY_DONT_SUBST
#include "ruby/subst.h"
#endif

#if !defined RUBY_EXPORT && !defined RUBY_NO_OLD_COMPATIBILITY
# include "ruby/backward.h"
#endif

RBIMPL_SYMBOL_EXPORT_END()

#endif /* RUBY_RUBY_H */

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