Hello pit,
On 01/20/2011 01:27 PM, pitpompej@xxxxxxxx wrote:
> I found a bug in the cpp-wrapper for the ftdi-lib that concerns nearly all
> open() functions of the Context-Class. All open-functions except the one with
> the usb_device parameter return with -1 (and error string "all fine") even if
> opening the device should be posssible (the ftdi-c version can open the same
> device). The reason for that behavior is, that they all use for the first
> connect to the device the correct ftdi-c-function concerning to the given
> parameters (open(vendor,pid) uses ftdi_usb_open(ftdi, vendor, product),
> open(description) uses ftdi_usb_open_string(ftdi, description.c_str()) and so
> on) but after the first connect they all use the ftdi_usb_get_strings
> function that needs as one parameter the usb_device. this has not been set
> before when using these special open-functions so it returns with an error
> and the open-function failes.
> I have already implemented a fix in my sources by adding to further functions
> in the ftdi-c-lib that returns by reference the usb_device ande changed the
> concerning calls in the cpp-wrapper. That all works fine for me now.
> But is a problem in the ftdi-cpp-wrapper worth a change in the ftdi-c-lib?
> I will try to commit it if possible today, otherwise next week.
Thanks for the report and your patch!
Looking at the C++ wrapper three years later,
I don't like the fact that I keeps an own "libusb_device *dev"
pointer -and- a pointer to the ftdi_context.
I think it can be improved without bloating the open()
function of the C API. Something like this:
- Remove the libusb_device pointer in the C++ wrapper
- Provide a function in the C API to get the strings without
closing the device. Thinking about it some more, the C API
could do this by default, "wasting" some bytes for an
already open device is a non-issue.
- Kill the get_strings_and_reopen() function
- Implement is_open() in the C API and kill the
"open" flag, too.
What do you think?
Cheers,
Thomas
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