GNU Radio 3.6.2-38 C++ API
hidapi API

Functions

int HID_API_EXPORT HID_API_CALL hid_init (void)
 Initialize the HIDAPI library.
int HID_API_EXPORT HID_API_CALL hid_exit (void)
 Finalize the HIDAPI library.
struct hid_device_info
HID_API_EXPORT *HID_API_CALL 
hid_enumerate (unsigned short vendor_id, unsigned short product_id)
 Enumerate the HID Devices.
void HID_API_EXPORT HID_API_CALL hid_free_enumeration (struct hid_device_info *devs)
 Free an enumeration Linked List.
HID_API_EXPORT hid_device
*HID_API_CALL 
hid_open (unsigned short vendor_id, unsigned short product_id, wchar_t *serial_number)
 Open a HID device using a Vendor ID (VID), Product ID (PID) and optionally a serial number.
HID_API_EXPORT hid_device
*HID_API_CALL 
hid_open_path (const char *path)
 Open a HID device by its path name.
int HID_API_EXPORT HID_API_CALL hid_write (hid_device *device, const unsigned char *data, size_t length)
 Write an Output report to a HID device.
int HID_API_EXPORT HID_API_CALL hid_read_timeout (hid_device *dev, unsigned char *data, size_t length, int milliseconds)
 Read an Input report from a HID device with timeout.
int HID_API_EXPORT HID_API_CALL hid_read (hid_device *device, unsigned char *data, size_t length)
 Read an Input report from a HID device.
int HID_API_EXPORT HID_API_CALL hid_set_nonblocking (hid_device *device, int nonblock)
 Set the device handle to be non-blocking.
int HID_API_EXPORT HID_API_CALL hid_send_feature_report (hid_device *device, const unsigned char *data, size_t length)
 Send a Feature report to the device.
int HID_API_EXPORT HID_API_CALL hid_get_feature_report (hid_device *device, unsigned char *data, size_t length)
 Get a feature report from a HID device.
void HID_API_EXPORT HID_API_CALL hid_close (hid_device *device)
 Close a HID device.
int HID_API_EXPORT_CALL hid_get_manufacturer_string (hid_device *device, wchar_t *string, size_t maxlen)
 Get The Manufacturer String from a HID device.
int HID_API_EXPORT_CALL hid_get_product_string (hid_device *device, wchar_t *string, size_t maxlen)
 Get The Product String from a HID device.
int HID_API_EXPORT_CALL hid_get_serial_number_string (hid_device *device, wchar_t *string, size_t maxlen)
 Get The Serial Number String from a HID device.
int HID_API_EXPORT_CALL hid_get_indexed_string (hid_device *device, int string_index, wchar_t *string, size_t maxlen)
 Get a string from a HID device, based on its string index.
HID_API_EXPORT const wchar_t
*HID_API_CALL 
hid_error (hid_device *device)
 Get a string describing the last error which occurred.

Function Documentation

Close a HID device.

Parameters:
deviceA device handle returned from hid_open().
struct hid_device_info HID_API_EXPORT* HID_API_CALL hid_enumerate ( unsigned short  vendor_id,
unsigned short  product_id 
) [read]

Enumerate the HID Devices.

This function returns a linked list of all the HID devices
attached to the system which match vendor_id and product_id.
If @p vendor_id and @p product_id are both set to 0, then
all HID devices will be returned.


@param vendor_id The Vendor ID (VID) of the types of device
        to open.
@param product_id The Product ID (PID) of the types of
        device to open.
Returns:
This function returns a pointer to a linked list of type struct hid_device, containing information about the HID devices attached to the system, or NULL in the case of failure. Free this linked list by calling hid_free_enumeration().
HID_API_EXPORT const wchar_t* HID_API_CALL hid_error ( hid_device device)

Get a string describing the last error which occurred.

Parameters:
deviceA device handle returned from hid_open().
Returns:
This function returns a string containing the last error which occurred or NULL if none has occurred.

Finalize the HIDAPI library.

This function frees all of the static data associated with
HIDAPI. It should be called at the end of execution to avoid
memory leaks.
Returns:
This function returns 0 on success and -1 on error.

Free an enumeration Linked List.

This function frees a linked list created by hid_enumerate().

                @param devs Pointer to a list of struct_device returned from
                          hid_enumerate().
int HID_API_EXPORT HID_API_CALL hid_get_feature_report ( hid_device device,
unsigned char *  data,
size_t  length 
)

Get a feature report from a HID device.

Make sure to set the first byte of data[] to the Report ID of the report to be read. Make sure to allow space for this extra byte in data[].

                    @param device A device handle returned from hid_open().
                    @param data A buffer to put the read data into, including
                            the Report ID. Set the first byte of @p data[] to the
                            Report ID of the report to be read.
                    @param length The number of bytes to read, including an
                            extra byte for the report ID. The buffer can be longer
                            than the actual report.

                    @returns
                            This function returns the number of bytes read and
                            -1 on error.
int HID_API_EXPORT_CALL hid_get_indexed_string ( hid_device device,
int  string_index,
wchar_t *  string,
size_t  maxlen 
)

Get a string from a HID device, based on its string index.

Parameters:
deviceA device handle returned from hid_open().
string_indexThe index of the string to get.
stringA wide string buffer to put the data into.
maxlenThe length of the buffer in multiples of wchar_t.
Returns:
This function returns 0 on success and -1 on error.
int HID_API_EXPORT_CALL hid_get_manufacturer_string ( hid_device device,
wchar_t *  string,
size_t  maxlen 
)

Get The Manufacturer String from a HID device.

Parameters:
deviceA device handle returned from hid_open().
stringA wide string buffer to put the data into.
maxlenThe length of the buffer in multiples of wchar_t.
Returns:
This function returns 0 on success and -1 on error.
int HID_API_EXPORT_CALL hid_get_product_string ( hid_device device,
wchar_t *  string,
size_t  maxlen 
)

Get The Product String from a HID device.

Parameters:
deviceA device handle returned from hid_open().
stringA wide string buffer to put the data into.
maxlenThe length of the buffer in multiples of wchar_t.
Returns:
This function returns 0 on success and -1 on error.
int HID_API_EXPORT_CALL hid_get_serial_number_string ( hid_device device,
wchar_t *  string,
size_t  maxlen 
)

Get The Serial Number String from a HID device.

Parameters:
deviceA device handle returned from hid_open().
stringA wide string buffer to put the data into.
maxlenThe length of the buffer in multiples of wchar_t.
Returns:
This function returns 0 on success and -1 on error.

Initialize the HIDAPI library.

This function initializes the HIDAPI library. Calling it is not strictly necessary, as it will be called automatically by hid_enumerate() and any of the hid_open_*() functions if it is needed. This function should be called at the beginning of execution however, if there is a chance of HIDAPI handles being opened by different threads simultaneously.

                    @returns
                            This function returns 0 on success and -1 on error.
HID_API_EXPORT hid_device* HID_API_CALL hid_open ( unsigned short  vendor_id,
unsigned short  product_id,
wchar_t *  serial_number 
)

Open a HID device using a Vendor ID (VID), Product ID (PID) and optionally a serial number.

If serial_number is NULL, the first device with the specified VID and PID is opened.

                    @param vendor_id The Vendor ID (VID) of the device to open.
                    @param product_id The Product ID (PID) of the device to open.
                    @param serial_number The Serial Number of the device to open
                                           (Optionally NULL).

                    @returns
                            This function returns a pointer to a #hid_device object on
                            success or NULL on failure.

Open a HID device by its path name.

The path name be determined by calling hid_enumerate(), or a
platform-specific path name can be used (eg: /dev/hidraw0 on
Linux).
Parameters:
pathThe path name of the device to open
@returns
        This function returns a pointer to a #hid_device object on
        success or NULL on failure.
int HID_API_EXPORT HID_API_CALL hid_read ( hid_device device,
unsigned char *  data,
size_t  length 
)

Read an Input report from a HID device.

Input reports are returned

to the host through the INTERRUPT IN endpoint. The first byte will contain the Report number if the device uses numbered reports.

                    @param device A device handle returned from hid_open().
                    @param data A buffer to put the read data into.
                    @param length The number of bytes to read. For devices with
                            multiple reports, make sure to read an extra byte for
                            the report number.

                    @returns
                            This function returns the actual number of bytes read and
                            -1 on error.
int HID_API_EXPORT HID_API_CALL hid_read_timeout ( hid_device dev,
unsigned char *  data,
size_t  length,
int  milliseconds 
)

Read an Input report from a HID device with timeout.

Input reports are returned to the host through the INTERRUPT IN endpoint. The first byte will contain the Report number if the device uses numbered reports.

                    @param dev A device handle returned from hid_open().
                    @param data A buffer to put the read data into.
                    @param length The number of bytes to read. For devices with
                            multiple reports, make sure to read an extra byte for
                            the report number.
                    @param milliseconds timeout in milliseconds or -1 for blocking wait.

                    @returns
                            This function returns the actual number of bytes read and
                            -1 on error.
int HID_API_EXPORT HID_API_CALL hid_send_feature_report ( hid_device device,
const unsigned char *  data,
size_t  length 
)

Send a Feature report to the device.

Feature reports are sent over the Control endpoint as a Set_Report transfer. The first byte of data[] must contain the Report ID. For devices which only support a single report, this must be set to 0x0. The remaining bytes contain the report data. Since the Report ID is mandatory, calls to hid_send_feature_report() will always contain one more byte than the report contains. For example, if a hid report is 16 bytes long, 17 bytes must be passed to hid_send_feature_report(): the Report ID (or 0x0, for devices which do not use numbered reports), followed by the report data (16 bytes). In this example, the length passed in would be 17.

                    @param device A device handle returned from hid_open().
                    @param data The data to send, including the report number as
                            the first byte.
                    @param length The length in bytes of the data to send, including
                            the report number.

                    @returns
                            This function returns the actual number of bytes written and
                            -1 on error.
int HID_API_EXPORT HID_API_CALL hid_set_nonblocking ( hid_device device,
int  nonblock 
)

Set the device handle to be non-blocking.

In non-blocking mode calls to hid_read() will return immediately with a value of 0 if there is no data to be read. In blocking mode, hid_read() will wait (block) until there is data to read before returning.

Nonblocking can be turned on and off at any time.

                    @param device A device handle returned from hid_open().
                    @param nonblock enable or not the nonblocking reads
                     - 1 to enable nonblocking
                     - 0 to disable nonblocking.

                    @returns
                            This function returns 0 on success and -1 on error.
int HID_API_EXPORT HID_API_CALL hid_write ( hid_device device,
const unsigned char *  data,
size_t  length 
)

Write an Output report to a HID device.

The first byte of data[] must contain the Report ID. For devices which only support a single report, this must be set to 0x0. The remaining bytes contain the report data. Since the Report ID is mandatory, calls to hid_write() will always contain one more byte than the report contains. For example, if a hid report is 16 bytes long, 17 bytes must be passed to hid_write(), the Report ID (or 0x0, for devices with a single report), followed by the report data (16 bytes). In this example, the length passed in would be 17.

hid_write() will send the data on the first OUT endpoint, if one exists. If it does not, it will send the data through the Control Endpoint (Endpoint 0).

                    @param device A device handle returned from hid_open().
                    @param data The data to send, including the report number as
                            the first byte.
                    @param length The length in bytes of the data to send.

                    @returns
                            This function returns the actual number of bytes written and
                            -1 on error.