Hi Matthias,
Am 12.05.2017 um 13:32 schrieb Matthias Janke:
> I'm using the c++ wrapper of libftdi (git co of yesterday) to
> communicate with a FT2232HL on a Lattice XO2 Eval board
> (LCMXO2-7000HE-B-EVN) this board has no programmed in iSerial.
>
> A simple c++ program which just opens and closes the device fails with
> "libusb_get_string_descriptor_ascii() failed" this is also true for
> the find_all_pp example (find_all, works). This failure originates in
> the use of the get_strings() function inside all c++ open() functions.
> This function wants all three iManufractuer, iProduct and iSerial to be
> present. The C-API allows one to pass NULL to ignore these descriptors.
> This is currently not possible with the c++ api. To properly fix this I
> suspect an api break is needed. As temporary ugly workaround I use the
> appended patch. Are there other ideas to fix this?
what about this open() function from ftdi.cpp:
int Context::open(int vendor, int product, const std::string&
description, const std::string& serial, unsigned int index)
{
// translate empty strings to NULL
// -> do not use them to find the device (vs. require an empty
string to be set in the EEPROM)
const char* c_description=NULL;
const char* c_serial=NULL;
if (!description.empty())
c_description=description.c_str();
if (!serial.empty())
c_serial=serial.c_str();
int ret = ftdi_usb_open_desc_index(d->ftdi, vendor, product,
c_description, c_serial, index);
if (ret < 0)
return ret;
return get_strings_and_reopen();
}
-> if you pass an empty string for "std::string serial",
it should pass down NULL for the serial parameter of the C API.
What happens if you use this specific open() function?
Cheers,
Thomas
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