// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library zx;

@transport("Syscall")
closed protocol Event {
    /// ## Summary
    ///
    /// Create an event.
    ///
    /// ## Declaration
    ///
    /// ```c
    /// #include <zircon/syscalls.h>
    ///
    /// zx_status_t zx_event_create(uint32_t options, zx_handle_t* out);
    /// ```
    ///
    /// ## Description
    ///
    /// `zx_event_create()` creates an event, which is an object that is signalable. That
    /// is, its `ZX_USER_SIGNAL_n` (where *n* is 0 through 7) signals can be
    /// manipulated using [`zx_object_signal()`].
    ///
    /// The newly-created handle will have the [basic
    /// rights](/docs/concepts/kernel/rights.md#zx_rights_basic) plus `ZX_RIGHT_SIGNAL`.
    ///
    /// ## Rights
    ///
    /// Caller job policy must allow `ZX_POL_NEW_EVENT`.
    ///
    /// ## Return value
    ///
    /// `zx_event_create()` returns `ZX_OK` and a valid event handle (via *out*) on success.
    /// On failure, an error value is returned.
    ///
    /// ## Errors
    ///
    /// `ZX_ERR_INVALID_ARGS`  *out* is an invalid pointer, or *options* is nonzero.
    ///
    /// `ZX_ERR_NO_MEMORY`  Failure due to lack of memory.
    /// There is no good way for userspace to handle this (unlikely) error.
    /// In a future build this error will no longer occur.
    ///
    /// ## See also
    ///
    ///  - [`zx_eventpair_create()`]
    ///  - [`zx_handle_close()`]
    ///  - [`zx_handle_duplicate()`]
    ///  - [`zx_handle_replace()`]
    ///  - [`zx_object_signal()`]
    ///  - [`zx_object_wait_async()`]
    ///  - [`zx_object_wait_many()`]
    ///  - [`zx_object_wait_one()`]
    ///
    /// [`zx_eventpair_create()`]: eventpair_create.md
    /// [`zx_handle_close()`]: handle_close.md
    /// [`zx_handle_duplicate()`]: handle_duplicate.md
    /// [`zx_handle_replace()`]: handle_replace.md
    /// [`zx_object_signal()`]: object_signal.md
    /// [`zx_object_wait_async()`]: object_wait_async.md
    /// [`zx_object_wait_many()`]: object_wait_many.md
    /// [`zx_object_wait_one()`]: object_wait_one.md
    strict Create(struct {
        options uint32;
    }) -> (resource struct {
        out Handle:EVENT;
    }) error Status;
};