CODEWITHSUNDEEP
pythonmutex
user1262882
user1262882

Reputation: 77

what is the difference between global and instance mutex in python

what is the difference between using mutex as a global variable or as an instance variable? for example, these two usages?:

my_lock = RLock()
class myclass:

    def __init__(self):
        self.mutex = my_lock
    def func():
        with self.mutex:
            #do something

and

class myclass:

    def __init__(self):
        self.mutex = RLock()
    def func():
        with self.mutex:
            #do something

Upvotes: 0

Views: 167

Answers (1)

Joachim Isaksson
Joachim Isaksson

Reputation: 181027

Your first version;

my_lock = RLock()
class myclass:

    def __init__(self):
        self.mutex = my_lock

...creates a single mutex common to all instances of the class, while

class myclass:

    def __init__(self):
        self.mutex = RLock()

...creates a mutex per instance.

In the first case, the mutex blocks func from executing simultaneously in any myclass object.

In the second case, the mutex blocks func from executing simultaneously in a single myclass object.

Upvotes: 1

Related Questions