IOHIDEventSystemClientScheduleWithRunLoop with EXC_BAD_ACCESS

Question

I\'m trying to get touch events in my application. So I used the IOHIDFamily callback to get the events. My code is like this:

void handle_event(void* target         


        

Answer 1

There's at least a couple problems I see in the code posted:

First, you are calling

CFRunLoopRun();

in the viewDidLoad method, which is going to be called on the main/UI thread. I see no reason for that, so just remove that line. I'd normally expect to see that call if you had a method that you were running on a background thread, and you needed to start a background run loop. Or, if you were registering for callbacks directly in main(), as in this answer.

Then, you have this:

void *ioHIDEventSystem = IOHIDEventSystemClientCreate(kCFAllocatorDefault);
IOHIDEventSystemClientScheduleWithRunLoop(system, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

I'm guessing the second line should be

IOHIDEventSystemClientScheduleWithRunLoop(ioHIDEventSystem, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);

I don't know what the system variable actually refers to, but it doesn't look right.

Take a look at this recent answer, as it seems to use IOKit correctly.