How to use delegate in NSStream? - objective-c

Question

I am a newbie in Objective-C. I am trying to learn how to work with NSStream. I just used simple code from Apple Support. This code should open a stream from a file in my Desktop and show a simple message when the delegate is called by iStream. At the end of the code, I can see the status is correct, but the delegate never gets called. What am I missing?
#import <Foundation/Foundation.h>
#interface MyDelegate: NSStream <NSStreamDelegate>{
}
- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode ;
#end
#implementation MyDelegate
- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
NSLog(#"############# in DELEGATE###############");
}
#end
int main(int argc, const char * argv[])
{
#autoreleasepool {
MyDelegate* myDelegate=[[MyDelegate alloc]init];
NSInputStream* iStream= [[NSInputStream alloc] initWithFileAtPath:#"/Users/Augend/Desktop/Test.rtf"];
[iStream setDelegate:myDelegate];
[iStream scheduleInRunLoop:[NSRunLoop currentRunLoop]
forMode:NSDefaultRunLoopMode];
[iStream open];
NSLog(#" status:%#",(NSString*) [iStream streamError]);
}
return 0;
}

Answer 1

The run loop isn't running long enough for the delegate method to be called.
Add:
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:2.0]];
right after you open the stream. This is only necessary in a program without a GUI -- otherwise the run loop would be spun for you.
If you want to be absolutely sure that stream:handleEvent: has been called before exiting, set a (global) flag in that method and put the runUntilDate: in a while loop that tests for the flag:
while( !delegateHasBeenNotified ){
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.5]];
}