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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2006-2018. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
/**
* @description: Poll interface functions
* @author Lukas Larsson
*
* The functions in the header are used to interact with the poll
* implementation. Iff the kernel-poll implementation needs a fallback
* pollset, then all functions are exported twice. Once with a _flbk
* suffix and once without any suffix. If no fallback is needed, then
* only the non-suffix version is exported.
*/
/**
* Initialize the poll implementation. Has to be called before any other function.
* @param[out] concurrent_waiters if not NULL, set to 1 if more then one thread
* is allowed to wait in the pollsets at the same time.
*/
void ERTS_POLL_EXPORT(erts_poll_init)(int *concurrent_waiters);
/**
* @brief Create a new pollset.
* @param id The unique debug id of this pollset.
*/
ErtsPollSet *ERTS_POLL_EXPORT(erts_poll_create_pollset)(int id);
/**
* Modify the contents of a pollset. This function can be called while one
* (or possibly more) thread is waiting in the pollset.
*
* @param ps the pollset to modify
* @param fd the file descriptor to modify
* @param op the type of operation to do. Normal usage is ADD,MOD...MOD,DEL.
* @param evts the events that we are changing interest to. Ignored if op is DEL.
* @param[in] wake_poller if set to 1 any thread waiting in the pollset will be woken.
* This parameter is ignored if the pollset supports concurrent waiters.
* @param[out] wake_poller set to 1 if the waiting thread was woken.
* @return The events set, or ERTS_POLL_EV_NVAL if it was not possible to add the
* fd to the pollset.
*/
ErtsPollEvents ERTS_POLL_EXPORT(erts_poll_control)(ErtsPollSet *ps,
ErtsSysFdType fd,
ErtsPollOp op,
ErtsPollEvents evts,
int *wake_poller);
/**
* Wait for events to be ready in the pollset. If the erts_poll_init call
* set concurrent_waiters to 1, then multiple threads are allowed to call
* this function at the same time.
*
* When an event has been triggered on a fd, that event is disabled. To
* re-enable it the implementation has to call erts_poll_control again.
*
* @param ps the pollset to wait for events in
* @param res an array of fd results that the ready fds are put in.
* @param[in] length the length of the res array
* @param[out] length the number of ready events returned in res
* @return 0 on success, else the ERRNO of the error that happened.
*/
int ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet *ps,
ErtsPollResFd res[],
int *length);
/**
* Interrupt the thread waiting in the pollset. This function should be called
* with set = 0 before any thread calls erts_poll_wait in order to clear any
* interrupts that have happened while the thread was awake.
*
* This function has no effect on pollsets that support concurrent waiters.
*
* @param ps the pollset to wake
* @param set if 1, interrupt the pollset, if 0 clear the interrupt flag.
*/
void ERTS_POLL_EXPORT(erts_poll_interrupt)(ErtsPollSet *ps, int set);
/* Debug functions */
/**
* Get the maximum number of fds supported by the pollset
*/
int ERTS_POLL_EXPORT(erts_poll_max_fds)(void);
/**
* Get information about the given pollset
*/
void ERTS_POLL_EXPORT(erts_poll_info)(ErtsPollSet *ps,
ErtsPollInfo *info);
/**
* Get information about which events are currently selected.
*
* The unix fd is used to index into the array, so naturally this function does
* not work on windows. If the pollset cannot figure out what the selected
* events for a given fd is, it is set to ERTS_POLL_EV_NONE.
*
* @param ps the pollset to get events from
* @param evts an array of which events are selected on.
*/
void ERTS_POLL_EXPORT(erts_poll_get_selected_events)(ErtsPollSet *ps,
ErtsPollEvents evts[],
int length);
#ifdef ERTS_ENABLE_LOCK_COUNT
/**
* Enable lock counting of any locks within the pollset.
*/
void ERTS_POLL_EXPORT(erts_lcnt_enable_pollset_lock_count)(ErtsPollSet *, int enable);
#endif
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