问macOS:用CGEventTap重写修饰符键

EN

#include <stdio.h>
#import <Carbon/Carbon.h>
#import <ApplicationServices/ApplicationServices.h>

CGEventRef loggerCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void* context)
{
    if (type == kCGEventFlagsChanged && CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode) == 54 /* right cmd key */) {
        printf(
            "TEST: %d %llu\n",
            type, 
            CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode)
        );
        CGKeyCode virtualKey = 0x3B; // kVK_Control (left control);
        CGEventRef override = CGEventCreateCopy(event);
        CGEventSetIntegerValueField(override, kCGKeyboardEventKeycode, virtualKey);
        return override;
    }
    return event;
}

int main(int argc, const char * argv[])
{

    CFMachPortRef tap;
    if ((tap = CGEventTapCreate(kCGHIDEventTap,
                                              kCGHeadInsertEventTap,
                                              0, kCGEventMaskForAllEvents,
                                              loggerCallback, NULL)) == NULL) {
        printf("Failed ot create event tap\n");
        exit(1);
    }
    CFRunLoopSourceRef runLoopSource;
    if ((runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, tap, 0)) == NULL) {
        printf("Failed to create run loop source\n");
        exit(1);
    }
    CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopCommonModes);
    CGEventTapEnable(tap, true);
    CFRunLoopRun();
    return 0;
}