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https://github.com/openvswitch/ovs
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5453ae2067
In C, one can do preprocessor tricks by making a macro expansion include
the macro's own name. We actually used this in the tree to automatically
provide function arguments, e.g.:
int f(int x, const char *file, int line);
#define f(x) f(x, __FILE__, __LINE__)
...
f(1); /* Expands to a call like f(1, __FILE__, __LINE__); */
However it's somewhat confusing, so this commit stops using that trick.
Reported-by: Ed Maste <emaste@freebsd.org>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ed Maste <emaste@freebsd.org>
74 lines
2.6 KiB
C
74 lines
2.6 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* High-level wrapper around the "poll" system call.
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*
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* The intended usage is for each thread's main loop to go about its business
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* servicing whatever events it needs to. Then, when it runs out of immediate
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* tasks, it calls each subordinate module's "wait" function, which in turn
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* calls one (or more) of the functions poll_fd_wait(), poll_immediate_wake(),
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* and poll_timer_wait() to register to be awakened when the appropriate event
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* occurs. Then the main loop calls poll_block(), which blocks until one of
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* the registered events happens.
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*
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*
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* Thread-safety
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* =============
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*
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* The poll set is per-thread, so all functions in this module are thread-safe.
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*/
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#ifndef POLL_LOOP_H
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#define POLL_LOOP_H 1
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#include <poll.h>
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#include "util.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Schedule events to wake up the following poll_block().
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*
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* The poll_loop logs the 'where' argument to each function at "debug" level
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* when an event causes a wakeup. Each of these ways to schedule an event has
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* a function and a macro wrapper. The macro version automatically supplies
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* the source code location of the caller. The function version allows the
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* caller to supply a location explicitly, which is useful if the caller's own
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* caller would be more useful in log output. See timer_wait_at() for an
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* example. */
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void poll_fd_wait_at(int fd, short int events, const char *where);
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#define poll_fd_wait(fd, events) poll_fd_wait_at(fd, events, SOURCE_LOCATOR)
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void poll_timer_wait_at(long long int msec, const char *where);
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#define poll_timer_wait(msec) poll_timer_wait_at(msec, SOURCE_LOCATOR)
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void poll_timer_wait_until_at(long long int msec, const char *where);
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#define poll_timer_wait_until(msec) \
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poll_timer_wait_until_at(msec, SOURCE_LOCATOR)
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void poll_immediate_wake_at(const char *where);
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#define poll_immediate_wake() poll_immediate_wake_at(SOURCE_LOCATOR)
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/* Wait until an event occurs. */
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void poll_block(void);
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#ifdef __cplusplus
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}
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#endif
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#endif /* poll-loop.h */
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