am7xxx-modeswitch: improve messages relative to libusb failures

diff --git a/examples/am7xxx-modeswitch.c b/examples/am7xxx-modeswitch.c
index f719f03..8e528c6 100644 (file)
--- a/examples/am7xxx-modeswitch.c
+++ b/examples/am7xxx-modeswitch.c
@@ -17,6 +17,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <errno.h>
 #include <libusb.h>
 
@@ -39,8 +40,11 @@ int main(void)
        unsigned int len;
 
        ret = libusb_init(NULL);
-       if (ret < 0)
+       if (ret < 0) {
+               fprintf(stderr, "libusb_init failed: %s\n",
+                       libusb_error_name(ret));
                goto out;
+       }
 
        libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_INFO);
 
@@ -48,14 +52,17 @@ int main(void)
                                                     AM7XXX_STORAGE_VID,
                                                     AM7XXX_STORAGE_PID);
        if (usb_device == NULL) {
-               fprintf(stderr, "cannot open the device: %d.\n", errno);
+               fprintf(stderr, "libusb_open failed: %s\n", strerror(errno));
                ret = -errno;
                goto out;
        }
 
        ret = libusb_set_configuration(usb_device, AM7XXX_STORAGE_CONFIGURATION);
        if (ret < 0) {
-               fprintf(stderr, "cannot set configuration.\n");
+               fprintf(stderr, "libusb_set_configuration failed: %s\n",
+                       libusb_error_name(ret));
+               fprintf(stderr, "Cannot set configuration %hhu\n",
+                       AM7XXX_STORAGE_CONFIGURATION);
                goto out_libusb_close;
        }
 
@@ -63,7 +70,10 @@ int main(void)
 
        ret = libusb_claim_interface(usb_device, AM7XXX_STORAGE_INTERFACE);
        if (ret < 0) {
-               fprintf(stderr, "cannot claim interface.\n");
+               fprintf(stderr, "libusb_claim_interface failed: %s\n",
+                       libusb_error_name(ret));
+               fprintf(stderr, "Cannot claim interface %hhu\n",
+                       AM7XXX_STORAGE_INTERFACE);
                goto out_libusb_close;
        }