Nested synchronized blocks in Objective-C

Asked May 17 '15 at 00:06

Active May 17 '15 at 01:14

Viewed 205 times

I read code somewhere in which multiple identical synchronized blocks are used, like this:

@implementation Test {
  NSObject var;
}

- (void)method1 {
  @synchronized(self) {
    @synchronized(var) {
     ...
    }
  }
}

- (void)method2 {
  @synchronized(self) {
    @synchronized(var) {
     ...
    }
  }
}

What's the rationale behind doing nested synchronized of self and var this way? Isn't @synchronized on var alone enough?

edited May 17 '15 at 01:14

asked May 17 '15 at 00:06

Boon

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Is `var` an instance variable, a global, or two separate local variables? – rmaddy May 17 '15 at 00:22
var is an instance variable. Edited example. – Boon May 17 '15 at 01:13
Maybe, maybe not. Without *a lot* more context it's hard to tell. (But you're getting into some dangerous territory.) – Hot Licks May 17 '15 at 13:00

Nested synchronized blocks in Objective-C

0 Answers0