napi_create_external_buffer.md

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added: v8.0.0
napiVersion: 1
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```c
napi_status napi_create_external_buffer(napi_env env,
                                        size_t length,
                                        void* data,
                                        napi_finalize finalize_cb,
                                        void* finalize_hint,
                                        napi_value* result)
```

* `[in] env`: The environment that the API is invoked under.
* `[in] length`: Size in bytes of the input buffer (should be the same as the
  size of the new buffer).
* `[in] data`: Raw pointer to the underlying buffer to expose to JavaScript.
* `[in] finalize_cb`: Optional callback to call when the `ArrayBuffer` is being
  collected. [`napi_finalize`][] provides more details.
* `[in] finalize_hint`: Optional hint to pass to the finalize callback during
  collection.
* `[out] result`: A `napi_value` representing a `node::Buffer`.

Returns `napi_ok` if the API succeeded.

This API allocates a `node::Buffer` object and initializes it with data
backed by the passed in buffer. While this is still a fully-supported data
structure, in most cases using a `TypedArray` will suffice.

The API adds a `napi_finalize` callback which will be called when the JavaScript
object just created is ready for garbage collection. It is similar to
`napi_wrap()` except that:

* the native data cannot be retrieved later using `napi_unwrap()`,
* nor can it be removed later using `napi_remove_wrap()`, and
* the object created by the API can be used with `napi_wrap()`.

For Node.js >=4 `Buffers` are `Uint8Array`s.