1 // Copyright 2020 The Pigweed Authors
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
7 // https://www.apache.org/licenses/LICENSE-2.0
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
16 #include "pw_chrono/system_clock.h"
17 #include "pw_sync/binary_semaphore.h"
21 inline BinarySemaphore::BinarySemaphore()
22 : native_type_{.mutex = {}, .condition = {}, .count = 0} {}
24 inline BinarySemaphore::~BinarySemaphore() {}
26 inline bool BinarySemaphore::try_acquire_for(
27 chrono::SystemClock::duration for_at_least) {
28 // Due to spurious condition variable wakeups we prefer not to use wait_for()
29 // as we may grossly extend the effective deadline after a spruious wakeup.
30 // Ergo we instead use the derived deadline which can be re-used many times
31 // without shifting the effective deadline. For more details on spurious
32 // wakeups and CVs on Windows and POSIX see:
33 // https://en.wikipedia.org/wiki/Spurious_wakeup
34 return try_acquire_until(chrono::SystemClock::now() + for_at_least);
37 inline BinarySemaphore::native_handle_type BinarySemaphore::native_handle() {
41 } // namespace pw::sync