Add debug message with libusb_open() error code

References #109.

diff --git a/libusb/core.c b/libusb/core.c
index f1c515c..5834bea 100644 (file)
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -944,6 +944,7 @@ int API_EXPORTED libusb_open(libusb_device *dev,
 
        r = usbi_backend->open(_handle);
        if (r < 0) {
+               usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
                libusb_unref_device(dev);
                usbi_mutex_destroy(&_handle->lock);
                free(_handle);