Race condition — это ситуация, когда результат работы программы зависит от того, в каком порядке выполняются ее части.
- Hızlı yanıt
- Arama sonuçları
- In programming, two main types of race conditions occur in a critical section of code, which is a section of code executed by multiple threads.
- In practice, many race conditions are caused by data races, and many data races lead to race conditions, but those two problems are not dependent on each other.
- What Are Computer Threads?# To explain a race condition, we first have to understand a little about how computers work internally.
- A race condition is a situation where multiple process access and manipulate the same data concurrently, and the outcome of the execution depends on the...
- Race condition in a logic circuit. Here, ∆t1 and ∆t2 represent the propagation delays of the logic elements. When the input value A changes from low to high...
- A race condition is a semantic error. It is a flaw that occurs in the timing or the ordering of events that leads to erroneous program behavior.
- Однако, с большой силой приходит большая ответственность. Конкурентность делает программы подверженными race condition.
- Под конец могу сказать, что гораздо полезнее выявлять Race Condition, чем Data Race, Data Race даже иногда может быть полезным и приводить к...
- You can easily imagine an infinite amount of different cases if you mix in more threads, resources, and time delays between operations. Race Condition in Code.
- Состояние гонки (race condition) — это ситуация, которая возникает в многозадачных или многопоточных программных системах...
Hızlı yanıt: kod örneği
A race condition occurs when two or more threads can access shared data and they try to change it at the same time. Because the thread scheduling algorithm can swap between threads at any time, you don't know the order in which the threads will attempt to access the shared data. Therefore, the result of the change in data is dependent on the thread scheduling algorithm, i.e. both threads are "racing" to access/change the data. Problems often occur when one thread does a "check-then-act" (e.g. "check" if the value is X, then "act" to do something that depends on the value being X) and another thread does something to the value in between the "check" and the "act". E.g:The point being, y could be 10, or it could be anything, depending on whether another thread changed x in between the check and act. You have no real way of knowing.In order to prevent race conditions from occurring, you would typically put a lock around the shared data to ensure only one thread can access the data at a time. This would mean something like this:
if (x == 5) // The "Check"{ y = x * 2; // The "Act" // If another thread changed x in between "if (x == 5)" and "y = x * 2" above, // y will not be equal to 10.}// Obtain lock for xif (x == 5){ y = x * 2; // Now, nothing can change x until the lock is released. // Therefore y = 10}// release lock for x