luo980/libuv
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

doc: improve documentation on uv_alloc_cb

Browse Source 
Refs: https://github.com/libuv/libuv/issues/1027#issuecomment-244386298
PR-URL: https://github.com/libuv/libuv/pull/1033
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Imran Iqbal <imran@imraniqbal.org>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
This commit is contained in:
Saúl Ibarra Corretgé 2016-09-07 09:48:36 +02:00
parent f046ebb409
commit bf0301c33c
1 changed files with 20 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
docs/src/handle.rst
View File

@ -24,12 +24,28 @@ Data types
.. c:type:: void (*uv_alloc_cb)(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) .. c:type:: void (*uv_alloc_cb)(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf)
Type definition for callback passed to :c:func:`uv_read_start` and Type definition for callback passed to :c:func:`uv_read_start` and
:c:func:`uv_udp_recv_start`. The user must fill the supplied :c:type:`uv_buf_t` :c:func:`uv_udp_recv_start`. The user must allocate memory and fill the supplied
structure with whatever size, as long as it's > 0. A suggested size (65536 at the moment) :c:type:`uv_buf_t` structure. If NULL is assigned as the buffer's base or 0 as its length,
is provided, but it doesn't need to be honored. Setting the buffer's length to 0 a ``UV_ENOBUFS`` error will be triggered in the :c:type:`uv_udp_recv_cb` or the
will trigger a ``UV_ENOBUFS`` error in the :c:type:`uv_udp_recv_cb` or
:c:type:`uv_read_cb` callback. :c:type:`uv_read_cb` callback.
A suggested size (65536 at the moment in most cases) is provided, but it's just an indication,
not related in any way to the pending data to be read. The user is free to allocate the amount
of memory they decide.
As an example, applications with custom allocation schemes such as using freelists, allocation
pools or slab based allocators may decide to use a different size which matches the memory
chunks they already have.
Example:
::
static void my_alloc_cb(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
buf->base = malloc(suggested_size);
buf->len = suggested_size;
}
.. c:type:: void (*uv_close_cb)(uv_handle_t* handle) .. c:type:: void (*uv_close_cb)(uv_handle_t* handle)
Type definition for callback passed to :c:func:`uv_close`. Type definition for callback passed to :c:func:`uv_close`.