Hi,I am working of USB HID devices. The IOHIDManagerOpen fails if the device is connected and application is launched. Below is the code where in I am registering for DeviceAttach and DeviceDetach event. I am able to recieve the attach and detach event, but IOHIDManagerOpen returns fails. In the event of failure I am not able to read or write to the device. Have I missed any thing while registering the device?#include <IOKit/hid/IOHIDManager.h>
#include <IOKit/hid/IOHIDKeys.h>
#include <CoreFoundation/CoreFoundation.h>
#include <pthread.h>
#include <sys/time.h>
#include <unistd.h>
//Reference : https://developer.apple.com/library/content/technotes/tn2187/_index.html
// this will be called when the HID Manager matches a new ( hot plugged ) HID device
static void Handle_DeviceMatchingCallback(
void * inContext, // context from IOHIDManagerRegisterDeviceMatchingCallback
IOReturn inResult, // the result of the matching operation
void * inSender, // the IOHIDManagerRef for the new device
IOHIDDeviceRef inIOHIDDeviceRef // the new HID device
) {
printf( "%s( context: %p, result: %x, sender: %p, device: %p ).\n",
__PRETTY_FUNCTION__, inContext, inResult, inSender, ( void* ) inIOHIDDeviceRef );
} // Handle_DeviceMatchingCallback
// this will be called when a HID device is removed ( unplugged )
static void Handle_RemovalCallback(
void * inContext, // context from IOHIDManagerRegisterDeviceMatchingCallback
IOReturn inResult, // the result of the removing operation
void * inSender, // the IOHIDManagerRef for the device being removed
IOHIDDeviceRef inIOHIDDeviceRef // the removed HID device
) {
printf( "%s( context: %p, result: %x, sender: %p, device: %p ).\n",
__PRETTY_FUNCTION__, inContext, inResult, inSender, ( void* ) inIOHIDDeviceRef );
} // Handle_RemovalCallback
int main(int argc, char const *argv[]) {
if (argc < 2) {
printf("usage:\n\t%s <vid>\n", argv[0]);
printf("for example: %s 0x04d8\n", argv[0]);
return 1;
}
IOOptionBits options = kIOHIDManagerOptionNone;
IOHIDManagerRef hidMgr = IOHIDManagerCreate(kCFAllocatorDefault, options);
if (hidMgr != NULL && CFGetTypeID(hidMgr) == IOHIDManagerGetTypeID()) {
printf("Successfully created HIDManager\n" );
long vid = strtol(argv[1], NULL, 16);
CFMutableDictionaryRef matchingDictRef = NULL;
if(vid) {
CFNumberRef vidRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &vid);
if(vidRef) {
matchingDictRef = CFDictionaryCreateMutable(kCFAllocatorDefault, 0 , &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
if(matchingDictRef) {
CFDictionarySetValue(matchingDictRef, CFSTR(kIOHIDVendorIDKey), vidRef);
} else {
printf("Failed to created mutable dictionary\n");
}
CFRelease(vidRef);
} else {
printf("Failed to create VID NumberRef\n");
}
}
IOHIDManagerSetDeviceMatching(hidMgr, matchingDictRef);
//Register for the call backs
IOHIDManagerRegisterDeviceMatchingCallback(hidMgr, Handle_DeviceMatchingCallback, NULL);
IOHIDManagerRegisterDeviceRemovalCallback(hidMgr, Handle_RemovalCallback, NULL);
IOHIDManagerScheduleWithRunLoop(hidMgr, CFRunLoopGetMain(), kCFRunLoopDefaultMode);
IOReturn tIOReturn = IOHIDManagerOpen( hidMgr, kIOHIDOptionsTypeNone );
if(tIOReturn != kIOReturnSuccess) {
printf("HIDManager faile to open -> %x\n",tIOReturn);
} else {
printf("HIDManager opened Successfully\n" );
}
} else {
return -1;
}
CFRunLoopRun();
return 0;
}Thanks,RV
Rashmi.