std::recursive_timed_mutex::try_lock_until

template< class Clock, class Duration >
bool try_lock_until( const std::chrono::time_point<Clock,Duration>& 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 program 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 be more or less 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 until after timeout_time has been reached due to process 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

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

#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