In particular HIDDescriptorListNode.cb has been renamed to
HIDDescriptorListNode.descriptor because it contains decriptor data
and not callbacks.
Moreover the HID_Descriptor.descriptor field has been renamed
to HID_Descriptor.data so the structure has now two fields length
and data.
typedef struct __attribute__((packed)) {
uint16_t length;
const void* data;
} HID_Descriptor;
class HIDDescriptorListNode {
public:
HIDDescriptorListNode *next = NULL;
const HID_Descriptor *descriptor;
HIDDescriptorListNode(const HID_Descriptor *d) : descriptor(d) { }
};
This imply a change in the use of the node from:
node->cb->lenght
node->cd->descriptor
to
node->descriptor->length
node->descriptor->data
This allows a sketch to find out the settings chosen by the USB host
(computer) and act accordingly.
Other than reading the DTR flag and checking if the baudrate is 1200,
the regular CDC code doesn't actually use any of these settings.
By exposing these settings to the sketch, it can for example copy them
to the hardware UART, turning the Leonardo into a proper USB-to-serial
device. This can be useful to let the computer directly talk to whatever
device is connected to the hardware serial port (like an XBee module).
The Teensy core already supported these methods. This code was
independently developed, but the method names were chosen to match the
Teensy code, for compatibility (except that `dtr()` and `rtr()` return
`bool`, while the Teensy version return a `uint8_t`).
This change is applied to both the avr and sam cores, which have a very
similar CDC implementation.
This uses the gnu11 standard, which is C11 with GNU extensions.
Previously, gnu89 was being used, which is pretty ancient by now. C99
brings some important improvements, some of which were already available
and used even without this option. C11 is more recent and brings more
minor improvements. Most notable feature is the static_assert statement,
allowing checking invariants at compiletime using the full C
expressions.
Gcc 4.8 defines __cplusplus as 201103L, so we can check for that now. It
still also defines __GXX_EXPERIMENTAL_CXX0X__, but this could help on
other compilers, or if gcc ever decides to stop defining the
experimental macro.
This uses the gnu++11 standard, which is C++11 with GNU extensions.
C++11 should be full compatible with the previously used C++98
standards, so all pre-existing sketches should continue to work.
