[libusb] Apple patches libusb for macOS to use USBDeviceOpen() instead of USBDeviceOpenSeize()

[Ludovic R. <lud...@gm...>]

Hello,

Apple provides my CCID driver in the standard macOS installation.
My driver uses libusb to access USB devices (smart card  readers).

>From the source code published by Apple you can see that they use a patch,
darwin_no_seize.patch [1], to replace USBDeviceOpenSeize() [2] by
USBDeviceOpen() [3]. The USB device is open with no exclusive access.

I have NO idea why Apple does that.
Also they use libusb 1.0.9 (released in April 2012).

I have not noticed a problem with the current libusb and its use of
USBDeviceOpenSeize() so I do not open a bug at libusb.
This email is just for information and history.

Regards,

[1]
https://opensource.apple.com/source/SmartcardCCID/SmartcardCCID-55017/libusb/files/darwin_no_seize.patch.auto.html
[2]
https://developer.apple.com/documentation/iokit/iousbdeviceinterface182/1559151-usbdeviceopenseize?language=objc
[3]
https://developer.apple.com/documentation/iokit/iousbdeviceinterface182/1559782-usbdeviceopen?language=objc

-- 
 Dr. Ludovic Rousseau