Properly initialize libusb in num_cards().

[bmusb] / bmusb.cpp

diff --git a/bmusb.cpp b/bmusb.cpp
index fd323a66ffc42bc8a025ba4e6353f7e7a6c37acd..e9a912524b25a25e809e2f8b35c275b3f1227236 100644 (file)
--- a/bmusb.cpp
+++ b/bmusb.cpp
@@ -1011,10 +1011,16 @@ libusb_device_handle *open_card(unsigned card_index, libusb_device *dev, string
 
 }  // namespace
 
-int BMUSBCapture::num_cards()
+unsigned BMUSBCapture::num_cards()
 {
+       int rc = libusb_init(nullptr);
+       if (rc < 0) {
+               fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(rc));
+               exit(1);
+       }
+
        vector<USBCardDevice> found_cards = find_all_cards();
-       int ret = found_cards.size();
+       unsigned ret = found_cards.size();
        for (size_t i = 0; i < found_cards.size(); ++i) {
                libusb_unref_device(found_cards[i].device);
        }