111 lines
3.7 KiB
C
111 lines
3.7 KiB
C
/*
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* Copyright(c) 2006 to 2019 ZettaScale Technology and others
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*
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* This program and the accompanying materials are made available under the
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* terms of the Eclipse Public License v. 2.0 which is available at
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* http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
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* v. 1.0 which is available at
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* http://www.eclipse.org/org/documents/edl-v10.php.
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*
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* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
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*/
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#ifndef Q_SOCKWAITSET_H
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#define Q_SOCKWAITSET_H
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#if defined (__cplusplus)
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extern "C" {
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#endif
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typedef struct os_sockWaitset * os_sockWaitset;
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typedef struct os_sockWaitsetCtx * os_sockWaitsetCtx;
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struct ddsi_tran_conn;
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/*
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Allocates a new connection waitset. The waitset is thread-safe in
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that multiple threads may add and remove connections from the wait set
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or trigger it. However only a single thread may process events from
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the wait set using the Wait and NextEvent functions in a single handling
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loop.
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*/
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os_sockWaitset os_sockWaitsetNew (void);
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/*
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Frees the waitset WS. Any connections associated with it will
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be closed.
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*/
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void os_sockWaitsetFree (os_sockWaitset ws);
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/*
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Triggers the waitset, from any thread. It is level
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triggered, when called while no thread is waiting in
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os_sockWaitsetWait the trigger will cause an (early) wakeup on the
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next call to os_sockWaitsetWait. Returns DDS_RETCODE_OK if
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successfully triggered, DDS_RETCODE_BAD_PARAMETER if an error occurs.
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Triggering a waitset may require resources and they may be counted.
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Do not trigger a waitset arbitrarily often without ensuring
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os_sockWaitsetWait is called often enough to let it release any
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resources used.
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Shared state updates preceding os_sockWaitsetTrigger are visible
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following os_sockWaitsetWait.
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*/
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void os_sockWaitsetTrigger (os_sockWaitset ws);
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/*
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A connection may be associated with only one waitset at any time, and
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may be added to the waitset only once. Failure to comply with this
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restriction results in undefined behaviour.
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Closing a connection associated with a waitset is handled gracefully: no
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operations will signal errors because of it.
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Returns < 0 on error, 0 if already present, 1 if added
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*/
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int os_sockWaitsetAdd (os_sockWaitset ws, struct ddsi_tran_conn * conn);
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/*
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Drops all connections from the waitset from index onwards. Index
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0 corresponds to the first connection added to the waitset, index 1 to
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the second, etc. Behaviour is undefined when called after a successful wait
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but before all events had been enumerated.
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*/
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void os_sockWaitsetPurge (os_sockWaitset ws, unsigned index);
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/*
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Waits until some of the connections in WS have data to be read.
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Returns a new wait set context if one or more connections have data to read.
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However, the return may be spurious (NULL) (i.e., no events)
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If a context is returned it must be enumerated before os_sockWaitsetWait
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may be called again.
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Shared state updates preceding os_sockWaitsetTrigger are visible
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following os_sockWaitsetWait.
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*/
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os_sockWaitsetCtx os_sockWaitsetWait (os_sockWaitset ws);
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/*
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Returns the index of the next triggered connection in the
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waitset contect ctx, or -1 if the set of available events has been
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exhausted. Index 0 is the first connection added to the waitset, index
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1 the second, &c.
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Following a call to os_sockWaitsetWait on waitset that returned
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a context, one MUST enumerate all available events before
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os_sockWaitsetWait may be called again.
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If the return value is >= 0, *conn contains the connection on which
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data is available.
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*/
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int os_sockWaitsetNextEvent (os_sockWaitsetCtx ctx, struct ddsi_tran_conn ** conn);
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/* Remove connection */
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void os_sockWaitsetRemove (os_sockWaitset ws, struct ddsi_tran_conn * conn);
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#if defined (__cplusplus)
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}
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#endif
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#endif /* Q_SOCKWAITSET_H */
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