I’m building a program with C++ by Mac Catalyst using Xcode to communicate with a composite hid device. I wrote a endless loop to test this function. Simply speaking , the process of my loop is as follows.

while(true){

1.Open HID interface with the composite HID device

2. If success, send “Get_FeatureReport” and get data from the device and print the result of the data

3. If success, close the interface and release the resource

4.Continue the loop

When I start the loop , I could always successfully get the correct data from the hid device , however , when it comes to 1020th iteration of the loop , it failed by Initialize failed with IOReturn = -536870201(0xE00002C7) by calling the following command.

kr = IOServiceOpen(usbInterface, mach_task_self(), pipRef, &connect);

And after that , it would always failed to open hid interface with the device unless I hot plug the device or restart the loop. During the failed case, system’s memory and CPU seems to be normal. I wonder that if might related with unreleased resource or maybe it’s because of the system limitation…I know that this is a critical case since user usually take such an action to communicate with the USB device , however , I still want to fix this issue in order to optimize my function’s code structure. Thank you for your patient for reading my question.

I tried to release all the resource such as io_iterator_t , usbInterface and etc.. but it always failed at 1020th iteration of the loop and after. Issue happened from the function of “IOReturn FindUSBInterface(IOUSBDeviceInterface245 **dev)”.

if (interfaceClass == kUSBHIDClass)
        {
            io_connect_t connect;

            UInt8       direction;
            UInt8       number;
            UInt8       transferType;
            UInt8       interval;
            
            if(count==1020)
                printf("1 0 2 0");
            kr = IOServiceOpen(usbInterface, mach_task_self(), pipRef, &connect);
            if (kr == kIOReturnSuccess)
            {
                kr = (*interface)->GetPipeProperties(interface, pipRef, &direction, &number, &transferType, &maxPacketSize, &interval);
                if (kr != kIOReturnSuccess || transferType != kUSBControl)
                {
                    (void) (*interface)->USBInterfaceClose(interface);
                    (void) (*interface)->Release(interface);
                    interface = NULL;
                    IOConnectRelease(connect);
                    continue;
                }
                    
                usbDeviceInterface = interface;
                IOObjectRelease(iterator);
                return kIOReturnSuccess;
            }
            else
            {
                IOConnectRelease(connect);
                IOObjectRelease(iterator);
                (void) (*interface)->USBInterfaceClose(interface);
                (void) (*interface)->Release(interface);
                interface = NULL;
                continue;
            }
        }
        else
        {
            (void) (*interface)->USBInterfaceClose(interface);
            (void) (*interface)->Release(interface);
            interface = NULL;
            continue;
        }