Question

I need to send a keystroke to the focused application, and my first searches led me to CGEventCreateKeyboardEvent:

CGEventRef eventA = CGEventCreateKeyboardEvent(NULL, (CGKeyCode)0, true);
CFRelease(eventA);

This compiled but didn’t do anything, but in the process of trying to figure it out I found this…

CGPostKeyboardEvent( (CGCharCode)'a', (CGKeyCode)0, true);

…and it worked. Why? From what I’ve read so far about this, they should be accomplishing the same thing, but CGPostKeyboardEvent is deprecated.

(Forgive me if I’m ignoring details that I should obviously include — I’m working way out my usual depth, trying to help colleagues with an extracurricular project, and just trying to learn a few things along the way.)

Answer 1

Your problem is that you’re not posting the event once you’ve created it. So the following code will press the left arrow and then release it:

CGEventRef a = CGEventCreateKeyboardEvent(NULL, 123, true);
CGEventRef b = CGEventCreateKeyboardEvent(NULL, 123, false);
CGEventPost(kCGHIDEventTap, a);
CGEventPost(kCGHIDEventTap, b);