Well-defined error codes for some operations

Also renamed set_interface_altsetting to set_interface_alt_setting for
better consistency

diff --git a/libusb/core.c b/libusb/core.c
index 3924eb2..479f919 100644 (file)
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -575,7 +575,11 @@ API_EXPORTED int libusb_set_configuration(libusb_device_handle *dev,
  * \param dev a device handle
  * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you
  * wish to claim
- * \returns 0 on success, or a LIBUSB_ERROR code on failure
+ * \returns 0 on success
+ * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist
+ * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the
+ * interface
+ * \returns a LIBUSB_ERROR code on other failure
  */
 API_EXPORTED int libusb_claim_interface(libusb_device_handle *dev,
        int interface_number)
@@ -632,11 +636,24 @@ out:
        return r;
 }
 
-/* FIXME docs */
-API_EXPORTED int libusb_set_interface_altsetting(libusb_device_handle *dev,
-       int interface_number, int altsetting)
+/** \ingroup dev
+ * Activate an alternate setting for an interface. The interface must have
+ * been previously claimed with libusb_claim_interface().
+ *
+ * \param dev a device handle
+ * \param interface_number the <tt>bInterfaceNumber</tt> of the
+ * previously-claimed interface
+ * \param altsetting the <tt>bAlternateSetting</tt> of the alternate setting
+ * to activate
+ * \returns 0 on success
+ * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the
+ * requested alternate setting does not exist
+ * \returns another LIBUSB_ERROR code on other failure
+ */
+API_EXPORTED int libusb_set_interface_alt_setting(libusb_device_handle *dev,
+       int interface_number, int alternate_setting)
 {
-       usbi_dbg("interface %d altsetting %d", interface_number, altsetting);
+       usbi_dbg("interface %d altsetting %d", interface_number, alternate_setting);
        if (interface_number >= sizeof(dev->claimed_interfaces) * 8)
                return LIBUSB_ERROR_INVALID_PARAM;
 
@@ -648,7 +665,7 @@ API_EXPORTED int libusb_set_interface_altsetting(libusb_device_handle *dev,
        pthread_mutex_unlock(&dev->lock);
 
        return usbi_backend->set_interface_altsetting(dev, interface_number,
-               altsetting);
+               alternate_setting);
 }
 
 /** \ingroup lib

diff --git a/libusb/libusb.h b/libusb/libusb.h
index e1dcf3a..dc88a16 100644 (file)
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -658,8 +658,8 @@ libusb_device_handle *libusb_open_device_with_vid_pid(uint16_t vendor_id,
        uint16_t product_id);
 
 
-int libusb_set_interface_altsetting(libusb_device_handle *dev, int iface,
-       int altsetting);
+int libusb_set_interface_alt_setting(libusb_device_handle *dev,
+       int interface_number, int alternate_setting);
 
 /* async I/O */
 

diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index 5849864..d1c1100 100644 (file)
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -442,8 +442,12 @@ static int op_claim_interface(struct libusb_device_handle *handle, int iface)
        int fd = __device_handle_priv(handle)->fd;
        int r = ioctl(fd, IOCTL_USBFS_CLAIMINTF, &iface);
        if (r) {
-               usbi_err("claim interface failed, error %d", r);
-               /* FIXME interpret error codes better */
+               if (errno == ENOENT)
+                       return LIBUSB_ERROR_NOT_FOUND;
+               else if (errno == EBUSY)
+                       return LIBUSB_ERROR_BUSY;
+
+               usbi_err("claim interface failed, error %d errno %d", r, errno);
                return LIBUSB_ERROR_OTHER;
        }
        return 0;
@@ -454,7 +458,7 @@ static int op_release_interface(struct libusb_device_handle *handle, int iface)
        int fd = __device_handle_priv(handle)->fd;
        int r = ioctl(fd, IOCTL_USBFS_RELEASEINTF, &iface);
        if (r) {
-               usbi_err("release interface failed, error %d", r);
+               usbi_err("release interface failed, error %d errno %d", r, errno);
                return LIBUSB_ERROR_OTHER;
        }
        return 0;
@@ -471,7 +475,10 @@ static int op_set_interface(struct libusb_device_handle *handle, int iface,
        setintf.altsetting = altsetting;
        r = ioctl(fd, IOCTL_USBFS_SETINTF, &setintf);
        if (r) {
-               usbi_err("setintf failed error %d", r);
+               if (errno == EINVAL)
+                       return LIBUSB_ERROR_NOT_FOUND;
+
+               usbi_err("setintf failed error %d errno %d", r, errno);
                return LIBUSB_ERROR_OTHER;
        }