FD 0 is a valid file descriptor

[mzyngier]

I may have reported this issue against a stale repository, so here it is again:

signal11/hidapi#462

Short story: File descriptor 0 is perfectly valid, and shouldn't be considered as an error.

hidapi/linux/hid.c

Lines 668 to 671 in d2c3a98

	dev->device_handle = open(path, O_RDWR);
	/* If we have a good handle, return it. */
	if (dev->device_handle > 0) {

[z3ntu]

Relevant part from open(2):

RETURN VALUE
open(), openat(), and creat() return the new file descriptor (a nonnegative integer), or -1 if an error occurred (in which case, errno is set appropriately).

[Youw]

(a nonnegative integer)

so I guess 0 is a nonnegative integer, looks valid

@mzyngier would you care to submit a PR?