RTypedData Struct Reference

"Typed" user data. More...

#include <rtypeddata.h>

Data Fields
struct RBasic	basic
	The part that all ruby objects have in common.
VALUE	fields_obj
	Direct reference to the slots that holds instance variables, if any.
const VALUE	type
	This is a const rb_data_type_t *const value, with the low bits set:
void *	data
	Pointer to the actual C level struct that you want to wrap.

Detailed Description

"Typed" user data.

By using this, extension libraries can wrap a C struct to make it visible from Ruby. For instance if you have a struct timeval, and you want users to use it,

static inline const rb_data_type_t timeval_type = {
    // Note that unspecified fields are 0-filled by default.
    .wrap_struct_name = "timeval",
    .function = {
        .dmark = nullptr,                 // no need to mark
        .dfree = RUBY_TYPED_DEFAULT_FREE, // use ruby_xfree()
        .dsize = [](auto) {
            return sizeof(struct timeval);
        },
    },
};
 
extern "C" void
Init_timeval(void)
{
    auto klass = rb_define_class("YourName", rb_cObject);
 
    rb_define_alloc_func(klass, [](auto klass) {
        struct timeval *t;
        auto ret = TypedData_Make_Struct(
           klass, struct timeval, &timeval_type, t);
 
        if (auto i = gettimeofday(t, nullptr); i == -1) {
            rb_sys_fail("gettimeofday(3)");
        }
        else {
            return ret;
        }
    });
}

Definition at line 358 of file rtypeddata.h.

Field Documentation

basic

struct RBasic RTypedData::basic

The part that all ruby objects have in common.

Definition at line 361 of file rtypeddata.h.

data

void* RTypedData::data

Pointer to the actual C level struct that you want to wrap.

Definition at line 378 of file rtypeddata.h.

Referenced by rb_data_typed_object_zalloc().

fields_obj

VALUE RTypedData::fields_obj

Direct reference to the slots that holds instance variables, if any.

Definition at line 364 of file rtypeddata.h.

type

const VALUE RTypedData::type

This is a const rb_data_type_t *const value, with the low bits set:

1: Set if object is embedded.

This field stores various information about how Ruby should handle a data. This roughly resembles a Ruby level class (apart from method definition etc.)

Definition at line 375 of file rtypeddata.h.

---

The documentation for this struct was generated from the following file:

• include/ruby/internal/core/rtypeddata.h