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std::recursive_timed_mutex::try_lock_until(3) | C++ Standard Libary | std::recursive_timed_mutex::try_lock_until(3) |
NAME¶
std::recursive_timed_mutex::try_lock_until - std::recursive_timed_mutex::try_lock_until
Synopsis¶
template< class Clock, class Duration >
bool try_lock_until( const std::chrono::time_point<Clock,Duration>&
(since C++11)
timeout_time );
Tries to lock the mutex. Blocks until specified timeout_time has been reached
or the
lock is acquired, whichever comes first. On successful lock acquisition
returns
true, otherwise returns false.
If timeout_time has already passed, this function behaves like
try_lock().
Clock must meet the Clock requirements.
The programs is ill-formed if std::chrono::is_clock_v<Clock> is false
(since C++20).
The standard recommends that the clock tied to timeout_time be used, in which
case
adjustments of the clock may be taken into account. Thus, the duration of the
block
might, but might not, be less or more than timeout_time - Clock::now() at the
time
of the call, depending on the direction of the adjustment and whether it is
honored
by the implementation. The function also may block for longer than until
after
timeout_time has been reached due to scheduling or resource contention
delays.
As with try_lock(), this function is allowed to fail spuriously and return
false
even if the mutex was not locked by any other thread at some point before
timeout_time.
Prior unlock() operation on the same mutex synchronizes-with (as defined in
std::memory_order) this operation if it returns true.
A thread may call try_lock_until on a recursive mutex repeatedly. Successful
calls
to try_lock_until increment the ownership count: the mutex will only be
released
after the thread makes a matching number of calls to unlock.
The maximum number of levels of ownership is unspecified. A call to
try_lock_until
will return false if this number is exceeded.
Parameters¶
timeout_time - maximum time point to block until
Return value¶
true if the lock was acquired successfully, otherwise false.
Exceptions¶
Any exception thrown by clock, time_point, or duration during the
execution (clocks,
time points, and durations provided by the standard library never throw)
Example¶
This example shows a 10 seconds block
// Run this code
#include <thread>
#include <iostream>
#include <chrono>
#include <mutex>
std::recursive_timed_mutex test_mutex;
void f()
{
auto now=std::chrono::steady_clock::now();
test_mutex.try_lock_until(now + std::chrono::seconds(10));
std::cout << "hello world\n";
}
int main()
{
std::lock_guard<std::recursive_timed_mutex> l(test_mutex);
std::thread t(f);
t.join();
}
See also¶
lock locks the mutex, blocks if the mutex is not available
(public member function)
try_lock tries to lock the mutex, returns if the mutex is not available
(public member function)
tries to lock the mutex, returns if the mutex has been
try_lock_for unavailable for the specified timeout duration
(public member function)
unlock unlocks the mutex
(public member function)
2022.07.31 | http://cppreference.com |