How to create a program to list all the USB devices in a Mac?

Question

I have a limited exposure to the Mac OS X operating system and now I have started using Xcode and am studying about I/O kit. I need to create a program in Xcode under command li

Answer 1

You can adapt USBPrivateDataSample to your needs, the sample sets up a notifier, lists the currently attached devices, then waits for device attach/detach. If you do, you will want to remove the usbVendor and usbProduct matching dictionaries, so all USB devices are matched.

Alternately, you can use IOServiceGetMatchingServices to get an iterator for all current matching services, using a dictionary created by IOServiceMatching(kIOUSBDeviceClassName).

Here's a short sample (which I've never run):

#include <IOKit/IOKitLib.h>
#include <IOKit/usb/IOUSBLib.h>

int main(int argc, const char *argv[])
{
    CFMutableDictionaryRef matchingDict;
    io_iterator_t iter;
    kern_return_t kr;
    io_service_t device;

    /* set up a matching dictionary for the class */
    matchingDict = IOServiceMatching(kIOUSBDeviceClassName);
    if (matchingDict == NULL)
    {
        return -1; // fail
    }

    /* Now we have a dictionary, get an iterator.*/
    kr = IOServiceGetMatchingServices(kIOMasterPortDefault, matchingDict, &iter);
    if (kr != KERN_SUCCESS)
    {
        return -1;
    }

    /* iterate */
    while ((device = IOIteratorNext(iter)))
    {
        /* do something with device, eg. check properties */
        /* ... */
        /* And free the reference taken before continuing to the next item */
        IOObjectRelease(device);
    }

   /* Done, release the iterator */
   IOObjectRelease(iter);
   return 0;
}

Answer 2

You just need to access the IOKit Registry. You may well be able to use the ioreg tool to do this (e.g. run it via system() or popen()). If not then you can at least use it to verify your code:

Info on ioreg tool:

$ man ioreg

Get list of USB devices:

$ ioreg -Src IOUSBDevice

Answer 3

If you run system_profiler SPUSBDataType it'll list all the USB devices connected to the system, you can then interact with that data either by dumping it into a text file or reading it from the command into the application and working with it there.