What are Objective-C #pragma marks?

#pragma mark -

This is actually an instruction to the IDE. It inserts a separator line into the navigation menu at that point, and also optional header text. It just makes it easier to find your way around a piece of code.

Example:

1. @interface GCStateMachine : NSObject 
2.  
3. @property (nonatomic, readonly) NSSet* states; 
4. @property (nonatomic, readonly) GCState* currentState; 
5.  
6. + (GCStateMachine*) stateMachineWithStates:(NSArray*) states; 
7.  
8. - (instancetype) initWithStates:(NSArray*) states; 
9. - (void) enterState:(Class) stateClass; 
10. - (void) updateWithDeltaTime:(NSTimeInterval) dt; 
11. - (GCState*) stateForClass:(Class) stateClass; 
12. - (BOOL) canEnterState:(Class) stateClass; 
13.  
14. @end 
15.  
16. #pragma mark - 
17.  
18. @interface GCState : NSObject 
19.  
20. @property (nonatomic, readonly) GCStateMachine* stateMachine; 
21.  
22. + (GCState*) state; 
23.  
24. - (BOOL) isValidNextState:(Class) state; 
25. - (void) didEnterWithPreviousState:(GCState*) previousState; 
26. - (void) willExitWithNextState:(GCState*) nextState; 
27. - (void) updateWithDeltaTime:(NSTimeInterval) dt; 
28.  
29. @end 

Here I declare two classes in one header file (I usually do this if the two classes are intimately bound to each other and are never used independently). The #pragma mark - between the two makes the navigation menu for this file look like this:

Note the separator line. This is the menu I use most of the time when navigating code, so it’s nice to have it laid out neatly.