![]() ![]() Each thread that needs a connection will acquire the semaphore for the duration of its use of a connection (which prevents too many threads asking for connections at once), but the pool object must also use synchronized blocks or methods when taking connections out of its internal collection or putting them back in, to prevent such things as losing track of connections or mistakenly handing the same connection to two different threads because they asked simultaneously. semaphore.c shows how to use these functions to create, operate and remove named semaphore. Suppose we have to allow at a time 10 members to access the Database and only 4 members are allowed to access Network Connection. You can look up manual pages for details of these functions. In Lock and RLock, at a time only one Thread is allowed to execute but sometimes our requirement is to execute a particular number of Threads at a time. We can limit the number of threads that can access the same resources. ![]() But Semaphore allows multiple threads to access the same resource at a time. In lock/Mutex, only one thread can access resources at a time. This is somewhat different from ordinary mutual exclusion or monitor locking, which is typically used to prevent more than one thread from simultaneously modifying the same variables and causing inconsistent results or program state.Ĭonsider, for example, a connection pool with a limit of 10 connections in it. Synchronization by using Semaphore in Python. Semaphore is a synchronization technique where we can control number of threads to access a resource. A semaphore acts as a limiter of available resource pool depth for example, a semaphore with a capacity of 10 allows a maximum of 10 threads to acquire it at once, and any further threads that attempt to acquire it will block until one of the other threads releases it.
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