libhpcalcs: portable (Windows / MacOS X / Linux) connectivity kit library

[debrouxl]

Hi Cristian

About your traces:
1) "unknown marker at beginning of image" means that the

Code:

if (pkt->data[8] == (uint8_t)format && pkt->data[9] == 0xFF && pkt->data[10] == 0xFF && pkt->data[11] == 0xFF && pkt->data[12] == 0xFF)

boolean condition for the data sent by the calculator is false. In that case, I'd need the full dump to see the data sent by the calculator... but I doubt the calculator has sent anything remotely correct, seeing that the last packet is all zeros: that's no valid ending for a PNG file.

2) the calculator replied nothing in 2 seconds. That seemed to be a safe timeout value, as screenshots always took much less than this.

3) the calculator was available when the test_hpcalcs program was started (otherwise you wouldn't have reached this step), but it looks like the calculator somehow disappeared from under the program.

4) communication with the calculator couldn't even be started, as opening the device, in the underlying HID library, failed. libhpcalcs / test_hpcalcs fails gracefully in that event, there's nothing else it can do (besides crashing, but that's no good ).

Bugginess in libhpcalcs is possible, but other reports until now tended to indicate it can work more consistently... and the first and last errors, especially, are hard to attribute to libhpcalcs (if communication fails completely, or returns garbage data, it can't do much).
Are you sure your calculator is in a stable state ?