Ruby
3.4.0dev (2024-11-05 revision e440268d51fe02b303e3817a7a733a0dac1c5091)
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Function overloads to issue warnings around ANYARGS. More...
#include "ruby/internal/attr/maybe_unused.h"
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/attr/weakref.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/config.h"
#include "ruby/internal/has/attribute.h"
#include "ruby/internal/intern/class.h"
#include "ruby/internal/intern/vm.h"
#include "ruby/internal/method.h"
#include "ruby/internal/value.h"
#include "ruby/backward/2/stdarg.h"
#include "ruby/backward/cxxanyargs.hpp"
Go to the source code of this file.
Macros | |
#define | RUBY_METHOD_FUNC(func) RBIMPL_CAST((VALUE (*)(ANYARGS))(func)) |
This macro is to properly cast a function parameter of *_define_method family. More... | |
Function overloads to issue warnings around ANYARGS.
RBIMPL
or rbimpl
are implementation details. Don't take them as canon. They could rapidly appear then vanish. The name (path) of this header file is also an implementation detail. Do not expect it to persist at the place it is now. Developers are free to move it anywhere anytime at will. __VA_ARGS__
is always available. We assume C99 for ruby itself but we don't assume languages of extension libraries. They could be written in C++98.For instance rb_define_method takes a pointer to ANYARGS -ed functions, which in fact varies 18 different prototypes. We still need to preserve ANYARGS for storages but why not check the consistencies if possible. With those complex macro overlays defined in this header file, use of a function pointer gets checked against the corresponding arity argument.
vm_method.c:call_cfunc_invoker_func()
. Note also that the 18 branches has lasted for at least 25 years. See also commit 200e0ee2fd3c1c006c528874a88f684447215524.__weakref__
thing?rb_define_method_00
is an alias of rb_define_method, with a strong type.Q: What is this __transparent_union__
thing?
A: That is another kind of function overloading mechanism that GCC provides. In this case the attributed function pointer is either VALUE(*)(int,VALUE*,VALUE)
or VALUE(*)(int,const VALUE*,VALUE)
.
This is better than void*
or ANYARGS because we can reject all other possibilities than the two.
vm_method.c:rb_add_method_cfunc()
. That should be handled by the __builtin_choose_expr
chain inside of rb_define_method macro expansion. In order to do so, comparison like (func == rb_f_notimplement)
is inappropriate for __builtin_choose_expr
's expression (which must be a compile-time integer constant but the address of rb_f_notimplement is not fixed until the linker). Instead we are using __builtin_types_compatible_p
, and in doing so we need to distinguish rb_f_notimplement from others, by type. Definition in file anyargs.h.
This macro is to properly cast a function parameter of *_define_method family.
It has been around since 1.x era so you can maximise backwards compatibility by using it.
func | A pointer to a function that implements a method. |