2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 /* High-level wrapper around the "poll" system call.
19 * Intended usage is for the program's main loop to go about its business
20 * servicing whatever events it needs to. Then, when it runs out of immediate
21 * tasks, it calls each subordinate module's "wait" function, which in turn
22 * calls one (or more) of the functions poll_fd_wait(), poll_immediate_wake(),
23 * and poll_timer_wait() to register to be awakened when the appropriate event
24 * occurs. Then the main loop calls poll_block(), which blocks until one of
25 * the registered events happens. */
39 /* Schedule events to wake up the following poll_block().
41 * The poll_loop logs the 'where' argument to each function at "debug" level
42 * when an event causes a wakeup. Ordinarily, it is automatically filled in
43 * with the location in the source of the call, and caller should therefore
44 * omit it. But, if the function you are implementing is very generic, so that
45 * its location in the source would not be very helpful for debugging, you can
46 * avoid the macro expansion and pass a different argument, e.g.:
47 * (poll_fd_wait)(fd, events, where);
48 * See timer_wait() for an example.
50 struct poll_waiter *poll_fd_wait(int fd, short int events, const char *where);
51 #define poll_fd_wait(fd, events) poll_fd_wait(fd, events, SOURCE_LOCATOR)
53 void poll_timer_wait(long long int msec, const char *where);
54 #define poll_timer_wait(msec) poll_timer_wait(msec, SOURCE_LOCATOR)
56 void poll_timer_wait_until(long long int msec, const char *where);
57 #define poll_timer_wait_until(msec) poll_timer_wait_until(msec, SOURCE_LOCATOR)
59 void poll_immediate_wake(const char *where);
60 #define poll_immediate_wake() poll_immediate_wake(SOURCE_LOCATOR)
62 /* Wait until an event occurs. */
63 void poll_block(void);
65 /* Cancel a file descriptor callback or event. */
66 void poll_cancel(struct poll_waiter *);
72 #endif /* poll-loop.h */