tildefriends/deps/libuv/docs/src/request.rst

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.. _request:
:c:type:`uv_req_t` --- Base request
===================================
`uv_req_t` is the base type for all libuv request types.
Structures are aligned so that any libuv request can be cast to `uv_req_t`.
All API functions defined here work with any request type.
Data types
----------
.. c:type:: uv_req_t
The base libuv request structure.
.. c:type:: uv_any_req
Union of all request types.
Public members
^^^^^^^^^^^^^^
.. c:member:: void* uv_req_t.data
Space for user-defined arbitrary data. libuv does not use this field.
.. c:member:: uv_req_type uv_req_t.type
Indicated the type of request. Readonly.
::
typedef enum {
UV_UNKNOWN_REQ = 0,
UV_REQ,
UV_CONNECT,
UV_WRITE,
UV_SHUTDOWN,
UV_UDP_SEND,
UV_FS,
UV_WORK,
UV_GETADDRINFO,
UV_GETNAMEINFO,
UV_REQ_TYPE_MAX,
} uv_req_type;
API
---
.. c:macro:: UV_REQ_TYPE_MAP(iter_macro)
Macro that expands to a series of invocations of `iter_macro` for
each of the request types. `iter_macro` is invoked with two
arguments: the name of the `uv_req_type` element without the `UV_`
prefix, and the name of the corresponding structure type without the
`uv_` prefix and `_t` suffix.
.. c:function:: int uv_cancel(uv_req_t* req)
Cancel a pending request. Fails if the request is executing or has finished
executing.
Returns 0 on success, or an error code < 0 on failure.
Only cancellation of :c:type:`uv_fs_t`, :c:type:`uv_getaddrinfo_t`,
:c:type:`uv_getnameinfo_t`, :c:type:`uv_random_t` and :c:type:`uv_work_t`
requests is currently supported.
Cancelled requests have their callbacks invoked some time in the future.
It's **not** safe to free the memory associated with the request until the
callback is called.
Here is how cancellation is reported to the callback:
* A :c:type:`uv_fs_t` request has its req->result field set to `UV_ECANCELED`.
* A :c:type:`uv_work_t`, :c:type:`uv_getaddrinfo_t`,
:c:type:`uv_getnameinfo_t` or :c:type:`uv_random_t` request has its
callback invoked with status == `UV_ECANCELED`.
.. c:function:: size_t uv_req_size(uv_req_type type)
Returns the size of the given request type. Useful for FFI binding writers
who don't want to know the structure layout.
.. c:function:: void* uv_req_get_data(const uv_req_t* req)
Returns `req->data`.
.. versionadded:: 1.19.0
.. c:function:: void* uv_req_set_data(uv_req_t* req, void* data)
Sets `req->data` to `data`.
.. versionadded:: 1.19.0
.. c:function:: uv_req_type uv_req_get_type(const uv_req_t* req)
Returns `req->type`.
.. versionadded:: 1.19.0
.. c:function:: const char* uv_req_type_name(uv_req_type type)
Returns the name for the equivalent struct for a given request type,
e.g. `"connect"` (as in :c:type:`uv_connect_t`) for `UV_CONNECT`.
If no such request type exists, this returns `NULL`.
.. versionadded:: 1.19.0