Trylockfor

Trylockfor is a pattern in concurrent programming that refers to attempting to acquire a mutex or lock for a bounded duration. The operation is designed to block only up to the specified time, after which it fails if the lock is not available. Because it includes a timeout, trylockfor helps avoid indefinite blocking and can be used to implement time-constrained tasks or to reduce the risk of deadlocks.

Across programming languages the exact name and return type vary, but the core idea is consistent. In C++ the equivalent is try_lock_for on timed mutexes, which takes a duration and returns a boolean indicating success. In Java, a similar concept appears as tryLock with a timeout, which also returns a boolean. In Rust and other languages that expose a locking API with timeouts, the call typically takes a duration and returns either an optional guard or a boolean indicating whether the lock was acquired. The common semantics are: wait up to the specified duration, acquire the lock if it becomes available, and otherwise give up and report failure.

Usage considerations include choosing an appropriate timeout to balance latency and throughput, handling the possibility of failure in a tolerant way, and ensuring that locked code paths remain short to minimize contention. Trylockfor is frequently used for coordinating time-sensitive tasks, performing periodic work while avoiding stalls, or implementing responsiveness in systems that require retries with bounded wait times. It is distinct from an unconditional lock (which may block indefinitely) and from a non-blocking try_lock (which returns immediately if the lock is unavailable).

See also: try_lock, lock with timeout, timed mutex, mutex guard, deadlock avoidance.