| (since C++14) |
Tries to lock the mutex. Blocks until specified timeout_duration has elapsed or the lock is acquired, whichever comes first. On successful lock acquisition returns true, otherwise returns false.
If timeout_duration is less or equal timeout_duration.zero(), the function behaves like try_lock().
A steady clock is used to measure the duration. This function may block for longer than timeout_duration 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 during timeout_duration.
Prior unlock() operation on the same mutex synchronizes-with (as defined in std::memory_order) this operation if it returns true.
If try_lock_for is called by a thread that already owns the mutex in any mode (shared or exclusive), the behavior is undefined.
Parameters
| timeout_duration | - | maximum duration to block for |
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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | #include <iostream>#include <mutex>#include <thread>#include <vector>#include <sstream> std::mutex cout_mutex; // control access to std::coutstd::timed_mutex mutex; void job(int id) { using Ms = std::chrono::milliseconds; std::ostringstream stream; for (int i = 0; i < 3; ++i) { if (mutex.try_lock_for(Ms(100))) { stream << "success "; std::this_thread::sleep_for(Ms(100)); mutex.unlock(); } else { stream << "failed "; } std::this_thread::sleep_for(Ms(100)); } std::lock_guard<std::mutex> lock(cout_mutex); std::cout << "[" << id << "] " << stream.str() << "\n";} int main() { std::vector<std::thread> threads; for (int i = 0; i < 4; ++i) { threads.emplace_back(job, i); } for (auto& i: threads) { i.join(); }} |
Possible output:
1 2 3 4 | [0] failed failed failed [3] failed failed success [2] failed success failed [1] success failed success |
See also
| locks the mutex, blocks if the mutex is not available (public member function) | |
| 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 unavailable until specified time point has been reached (public member function) | |
| unlocks the mutex (public member function) |
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