multithreading - In Objective-c how do I ensure that one code is called after another code? -


i don't mean synchronize , stuff. not in general programming practice actually. think there should done.

for example, have thread suspend self , wait till event occur. event occur before thread suspend itself.

so want event wait till thread suspend before occurs.

how do that?

for example, want 5 things on mainqueue.

do something. wait till it's finished, next.

i then:

-(void) vdosomestuffsinsequence:(nsarray *) arblarrayofblockstoexecuteonmainthread {     if (self.blockthis) {         po(@"cancel push view controller");         return;     }     @synchronized(self)     {         self.blockthis=true;     }     assertmainthread      nsmutablearray * arblnotfirstblocks = [arblarrayofblockstoexecuteonmainthread mutablecopy];      void(^blocktoexecute)() = arblnotfirstblocks[0];//execute first block right away     blocktoexecute();     po(@"execute pop push etc");     [arblnotfirstblocks removeobjectatindex:0];       [[nsoperationqueue new] addoperationwithblock:^{         po(@"before first suspend");         [self vsuspendandhaltthisthreadtillunsuspended]; //this happen after (instead of before) code execute [self vcontinue called]         po(@"after first suspend");         (void(^blocktoexecute)() in arblnotfirstblocks) {              while(false);             [[nsoperationqueue mainqueue] addoperationwithblock:^{                 blocktoexecute();//dothisfirst must unsuspend thread somewhere             }];              [self vsuspendandhaltthisthreadtillunsuspended];         }         [[nsoperationqueue mainqueue]addoperationwithblock:^{             @synchronized(self)             {                 self.blockthis=false;             }             [self vcontinue];         }];         [self vsuspendandhaltthisthreadtillunsuspended];         po(@"finish vdosomestuffsinsequence");     }]; }

polling, waiting, , long or indefinite thread or resource blocking best avoided. nevertheless... can wait using condition variables, dispatch_group_wait, or -[nsoperationqueue waituntilalloperationsarefinished].


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