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2.12 kBMarkdownView Raw
1## Buffers
2
3NAN's `node::Buffer` helpers exist as the API has changed across supported Node versions. Use these methods to ensure compatibility.
4
5 - <a href="#api_nan_new_buffer"><b><code>Nan::NewBuffer()</code></b></a>
6 - <a href="#api_nan_copy_buffer"><b><code>Nan::CopyBuffer()</code></b></a>
7 - <a href="#api_nan_free_callback"><b><code>Nan::FreeCallback()</code></b></a>
8
9<a name="api_nan_new_buffer"></a>
10### Nan::NewBuffer()
11
12Allocate a new `node::Buffer` object with the specified size and optional data. Calls `node::Buffer::New()`.
13
14Note that when creating a `Buffer` using `Nan::NewBuffer()` and an existing `char*`, it is assumed that the ownership of the pointer is being transferred to the new `Buffer` for management.
15When a `node::Buffer` instance is garbage collected and a `FreeCallback` has not been specified, `data` will be disposed of via a call to `free()`.
16You _must not_ free the memory space manually once you have created a `Buffer` in this way.
17
18Signature:
19
20```c++
21Nan::MaybeLocal<v8::Object> Nan::NewBuffer(uint32_t size)
22Nan::MaybeLocal<v8::Object> Nan::NewBuffer(char* data, uint32_t size)
23Nan::MaybeLocal<v8::Object> Nan::NewBuffer(char *data,
24 size_t length,
25 Nan::FreeCallback callback,
26 void *hint)
27```
28
29
30<a name="api_nan_copy_buffer"></a>
31### Nan::CopyBuffer()
32
33Similar to [`Nan::NewBuffer()`](#api_nan_new_buffer) except that an implicit memcpy will occur within Node. Calls `node::Buffer::Copy()`.
34
35Management of the `char*` is left to the user, you should manually free the memory space if necessary as the new `Buffer` will have its own copy.
36
37Signature:
38
39```c++
40Nan::MaybeLocal<v8::Object> Nan::CopyBuffer(const char *data, uint32_t size)
41```
42
43
44<a name="api_nan_free_callback"></a>
45### Nan::FreeCallback()
46
47A free callback that can be provided to [`Nan::NewBuffer()`](#api_nan_new_buffer).
48The supplied callback will be invoked when the `Buffer` undergoes garbage collection.
49
50Signature:
51
52```c++
53typedef void (*FreeCallback)(char *data, void *hint);
54```