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|
SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
brief: |
Receives or gets an event set.
copyrights:
- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
definition:
default:
body: null
params:
- ${set:/name} ${.:/params[0]/name}
- ${../../option/if/option:/name} ${.:/params[1]/name}
- ${../../type/if/interval:/name} ${.:/params[2]/name}
- ${set:/name} *${.:/params[3]/name}
return: ${../../status/if/code:/name}
variants: []
description: |
This directive can be used to
* get the pending events of the calling task, or
* receive events.
To *get the pending events* use the constant ${pending-events:/name} for the
``${.:/params[0]/name}`` parameter. The pending events are returned to the
calling task but the event set of the task is left unaltered. The
``${.:/params[1]/name}`` and ``${.:params[2]/name}`` parameters are ignored
in this case. The directive returns immediately and does not block.
To *receive events* you have to define an input event condition and some
options. The option set specified in ``${.:/params[1]/name}`` defines
* if the task will wait or poll for the events, and
* if the task wants to receive all or any of the input events.
The option set is built through a *bitwise or* of the option constants
described below.
The task can *wait* or *poll* for the events.
* Waiting for events is the default and can be emphasized through the use of
the ${../../option/if/wait:/name} option. The ``${.:/params[2]/name}``
parameter defines how long the task is willing to wait. Use
${../../type/if/no-timeout:/name} to wait potentially forever, otherwise set a
timeout interval in clock ticks.
* Not waiting for events (polling) is selected by the
${../../option/if/no-wait:/name} option. If this option is defined, then the
``${.:/params[2]/name}`` parameter is ignored.
The task can receive *all* or *any* of the input events specified in
``${.:/params[0]/name}``.
* Receiving all input events is the default and can be emphasized through the use
of the ${../../option/if/event-all:/name} option.
* Receiving any of the input events is selected by the
${../../option/if/event-any:/name} option.
To receive all events use the constant ${all-events:/name} for the
``${.:/params[0]/name}`` parameter. This constant is identical to
${event-0:/name} | ... | ${event-31:/name} and should not be confused with
the option ${../../option/if/event-all:/name}.
enabled-by: true
interface-type: function
links:
- role: interface-placement
uid: header
- role: interface-ingroup
uid: group
name: rtems_event_receive
notes: |
This directive shall be called by a task. Calling this directive from
interrupt context is undefined behaviour.
This directive only affects the events specified in ``${.:/params[0]/name}``.
Any pending events that do not correspond to any of the events specified in
``${.:/params[0]/name}`` will be left pending.
A task can *receive all of the pending events* by calling the directive with
a value of ${all-events:/name} for the ``${.:/params[0]/name}`` parameter and
${../../option/if/no-wait:/name} | ${../../option/if/event-any:/name} for the
``${.:/params[1]/name}`` parameter. The pending events are returned to the
calling task and the event set of the task is cleared. If no events are
pending then the ${../../status/if/unsatisfied:/name} status code will be returned.
params:
- description: |
is the event set of interest. Use ${pending-events:/name} to get the
pending events.
dir: null
name: event_in
- description: is the option set.
dir: null
name: option_set
- description: |
is the timeout in clock ticks if the ${../../option/if/wait:/name} option was
set. Use ${../../type/if/no-timeout:/name} to wait potentially forever.
dir: null
name: ticks
- description: |
is the pointer to an event set. The received or pending events are stored
in the referenced event set if the operation was successful.
dir: null
name: event_out
return:
return: null
return-values:
- description: |
The requested operation was successful.
value: ${../../status/if/successful:/name}
- description: |
The ``${.:/params[3]/name}`` parameter was ${/c/if/null:/name}.
value: ${../../status/if/invalid-address:/name}
- description: |
The events of interest were not immediately available.
value: ${../../status/if/unsatisfied:/name}
- description: |
The events of interest were not available within the specified timeout
interval.
value: ${../../status/if/timeout:/name}
type: interface
|
