Several run methods of Runloop

Running a Loop1,run:

Puts the receiver into a permanent loop, during which time it processes data from all attached input sources.

Discussion

If no input sources or timers is attached to the run loop, this method exits immediately;

Otherwise, it runs the receiver in the Nsdefaultrunloopmode by repeatedly invoking runmode:befored Ate:.

In other words, this method effectively begins a infinite loop that processes data from the run loop ' s input sources and Timers.

Manually removing all known input sources and timers from the run loop are not a guarantee that the run loop would exit. OS X can install and remove additional input sources as needed to process requests targeted at the receiver ' s thread. Those sources could therefore prevent the run loop from exiting.

If you want the "run loop to terminate", you shouldn ' t use this method. Instead, use one of the other run methods and also check other arbitrary conditions of your own, in a loop. A Simple example would is:

BOOL shouldkeeprunning = YES; Globalnsrunloop *therl = [Nsrunloop currentrunloop];while (shouldkeeprunning && [Therl runmode: Nsdefaultrunloopmode beforedate:[nsdate Distantfuture]]);

Where shouldkeeprunning is set to NO somewhere else in the program.

2,-runmode:beforedate:

Runs the loop once, blocking for input in the specified mode until a given date.

Return Value

YES If the run loop ran and processed an input source or if the specified timeout value is reached; Otherwise,no If the run loop could not be started.

Discussion

If no input sources or timers is attached to the run loop, this method exits immediately and returns no;

Otherwise, it returns after either the first input source is processed or limitdate is reached. (only one event is processed at a time, so rununtildate and run will call this method in a loop)

Manually removing all known input sources and timers from the run loop does not guarantee, that the run loop would exit Imme Diately. OS X may install and remove additional input sources as needed to process requests targeted at the receiver ' s thread. Those sources could therefore prevent the run loop from exiting.

NOTE

A timer is not considered an input source and may fire multiple times while waiting for this method to return

3,-rununtildate:

If no input sources or timers is attached to the run loop, this method exits immediately;

Otherwise, it runs the receiver in the Nsdefaultrunloopmode by repeatedly invoking Runmode:beforedate:u Ntil the specified expiration date.

Several run methods of Runloop