ardupilot/libraries/AP_Common/Semaphore.h

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/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
2018-08-19 07:11:32 -03:00
#pragma once
#pragma once
/*
a method to make semaphores less error prone. The WITH_SEMAPHORE()
macro will block forever for a semaphore, and will automatically
release the semaphore when it goes out of scope
Note that we have two types of semaphores. A normal semaphore can
only be taken once. A recursive semaphore allows for the thread
holding the semaphore to take it again. It must be released the same
number of times it is taken.
The WITH_SEMAPHORE() macro can be used with either type of semaphore
*/
class WithSemaphore {
public:
WithSemaphore(HAL_Semaphore &mtx) :
_mtx(mtx)
{
_mtx.take_blocking();
}
~WithSemaphore() {
_mtx.give();
}
private:
HAL_Semaphore &_mtx;
};
#define WITH_SEMAPHORE(sem) WithSemaphore _getsem(sem)