Add getter/setter functions for the fields of public structs that might be relevant to e.g. Node.js addons. Through these methods, ABI compatibility for a subset of the ABI is easier to achieve, since using them makes code independent of the exact offsets of these fields. The intended use case that prompted this are N-API addons for Node.js, which look for more long-term ABI compatibility guarantees than typical Node code. With these helper functions, using libuv directly should no longer be an obstacle for such addons. PR-URL: https://github.com/libuv/libuv/pull/1657 Refs: https://github.com/nodejs/node/issues/13512 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
110 lines
2.7 KiB
ReStructuredText
110 lines
2.7 KiB
ReStructuredText
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.. _request:
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:c:type:`uv_req_t` --- Base request
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===================================
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`uv_req_t` is the base type for all libuv request types.
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Structures are aligned so that any libuv request can be cast to `uv_req_t`.
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All API functions defined here work with any request type.
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Data types
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----------
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.. c:type:: uv_req_t
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The base libuv request structure.
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.. c:type:: uv_any_req
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Union of all request types.
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Public members
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^^^^^^^^^^^^^^
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.. c:member:: void* uv_req_t.data
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Space for user-defined arbitrary data. libuv does not use this field.
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.. c:member:: uv_req_type uv_req_t.type
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Indicated the type of request. Readonly.
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::
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typedef enum {
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UV_UNKNOWN_REQ = 0,
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UV_REQ,
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UV_CONNECT,
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UV_WRITE,
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UV_SHUTDOWN,
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UV_UDP_SEND,
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UV_FS,
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UV_WORK,
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UV_GETADDRINFO,
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UV_GETNAMEINFO,
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UV_REQ_TYPE_PRIVATE,
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UV_REQ_TYPE_MAX,
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} uv_req_type;
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API
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---
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.. c:function:: int uv_cancel(uv_req_t* req)
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Cancel a pending request. Fails if the request is executing or has finished
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executing.
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Returns 0 on success, or an error code < 0 on failure.
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Only cancellation of :c:type:`uv_fs_t`, :c:type:`uv_getaddrinfo_t`,
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:c:type:`uv_getnameinfo_t` and :c:type:`uv_work_t` requests is
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currently supported.
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Cancelled requests have their callbacks invoked some time in the future.
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It's **not** safe to free the memory associated with the request until the
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callback is called.
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Here is how cancellation is reported to the callback:
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* A :c:type:`uv_fs_t` request has its req->result field set to `UV_ECANCELED`.
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* A :c:type:`uv_work_t`, :c:type:`uv_getaddrinfo_t` or c:type:`uv_getnameinfo_t`
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request has its callback invoked with status == `UV_ECANCELED`.
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.. c:function:: size_t uv_req_size(uv_req_type type)
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Returns the size of the given request type. Useful for FFI binding writers
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who don't want to know the structure layout.
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.. c:function:: void* uv_req_get_data(const uv_req_t* req)
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Returns `req->data`.
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.. versionadded:: 1.19.0
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.. c:function:: void* uv_req_set_data(uv_req_t* req, void* data)
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Sets `req->data` to `data`.
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.. versionadded:: 1.19.0
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.. c:function:: uv_req_type uv_req_get_type(const uv_req_t* req)
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Returns `req->type`.
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.. versionadded:: 1.19.0
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.. c:function:: const char* uv_req_type_name(uv_req_type type)
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Returns the name for the equivalent struct for a given request type,
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e.g. `"connect"` (as in :c:type:`uv_connect_t`) for `UV_CONNECT`.
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If no such request type exists, this returns `NULL`.
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.. versionadded:: 1.19.0
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