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Initialize the HIDAPI library.

This function initializes the HIDAPI library. Calling it is not strictly necessary, as it will be called automatically by SDL_hid_enumerate() and any of the SDL_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.

Each call to this function should have a matching call to SDL_hid_exit()

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

See also

sDL_hid_exit

C declaration

SDL_hid_init, defined at SDL3/SDL_hidapi.h 177:33

Since: 3.2.0

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

0 on success or a negative error code on failure; call SDL_GetError() for more information.

See also

sDL_hid_init

C declaration

SDL_hid_exit, defined at SDL3/SDL_hidapi.h 192:33

Since: 3.2.0

Check to see if devices may have been added or removed.

Enumerating the HID devices is an expensive operation, so you can call this to see if there have been any system device changes since the last call to this function. A change in the counter returned doesn't necessarily mean that anything has changed, but you can call SDL_hid_enumerate() to get an updated device list.

Calling this function for the first time may cause a thread or other system resource to be allocated to track device change notifications.

Returns

a change counter that is incremented with each potential device change, or 0 if device change detection isn't available.

See also

sDL_hid_enumerate

C declaration

SDL_hid_device_change_count, defined at SDL3/SDL_hidapi.h 213:36

Since: 3.2.0

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 vendor_id is set to 0 then any vendor matches. If product_id is set to 0 then any product matches. If vendor_id and product_id are both set to 0, then all HID devices will be returned.

By default SDL will only enumerate controllers, to reduce risk of hanging or crashing on bad drivers, but SDL_HINT_HIDAPI_ENUMERATE_ONLY_CONTROLLERS can be set to "0" to enumerate all HID devices.

Returns

a pointer to a linked list of type SDL_hid_device_info, containing information about the HID devices attached to the system, or NULL in the case of failure. Free this linked list by calling SDL_hid_free_enumeration().

See also

sDL_hid_device_change_count

C declaration

SDL_hid_enumerate, defined at SDL3/SDL_hidapi.h 241:51

Since: 3.2.0

Free an enumeration linked list.

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

C declaration

SDL_hid_free_enumeration, defined at SDL3/SDL_hidapi.h 253:34

Since: 3.2.0

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.

Returns

a pointer to a SDL_hid_device object on success or NULL on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_open, defined at SDL3/SDL_hidapi.h 271:46

Since: 3.2.0

Open a HID device by its path name.

The path name be determined by calling SDL_hid_enumerate(), or a platform-specific path name can be used (eg: /dev/hidraw0 on Linux).

Returns

a pointer to a SDL_hid_device object on success or NULL on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_open_path, defined at SDL3/SDL_hidapi.h 285:46

Since: 3.2.0

Get the properties associated with an SDL_hid_device.

The following read-only properties are provided by SDL:

• sDL_PROP_HIDAPI_LIBUSB_DEVICE_HANDLE_POINTER: the libusb_device_handle associated with the device, if it was opened using libusb.

Returns

a valid property ID on success or 0 on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_properties, defined at SDL3/SDL_hidapi.h 301:46

Since: 3.4.0

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 SDL_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 SDL_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.

SDL_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).

Returns

the actual number of bytes written and -1 on on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_write, defined at SDL3/SDL_hidapi.h 330:33

Since: 3.2.0

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.

Returns

the actual number of bytes read and -1 on on failure; call SDL_GetError() for more information. If no packet was available to be read within the timeout period, this function returns 0.

C declaration

SDL_hid_read_timeout, defined at SDL3/SDL_hidapi.h 351:33

Since: 3.2.0

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.

Returns

the actual number of bytes read and -1 on failure; call SDL_GetError() for more information. If no packet was available to be read and the handle is in non-blocking mode, this function returns 0.

C declaration

SDL_hid_read, defined at SDL3/SDL_hidapi.h 372:33

Since: 3.2.0

Set the device handle to be non-blocking.

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

Nonblocking can be turned on and off at any time.

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_set_nonblocking, defined at SDL3/SDL_hidapi.h 391:33

Since: 3.2.0

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 SDL_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 SDL_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.

Returns

the actual number of bytes written and -1 on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_send_feature_report, defined at SDL3/SDL_hidapi.h 416:33

Since: 3.2.0

Get a feature report from a HID device.

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. Upon return, the first byte will still contain the Report ID, and the report data will start in data[1].

Returns

the number of bytes read plus one for the report ID (which is still in the first byte), or -1 on on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_feature_report, defined at SDL3/SDL_hidapi.h 439:33

Since: 3.2.0

Get an input report from a HID device.

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. Upon return, the first byte will still contain the Report ID, and the report data will start in data[1].

Returns

the number of bytes read plus one for the report ID (which is still in the first byte), or -1 on on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_input_report, defined at SDL3/SDL_hidapi.h 462:33

Since: 3.2.0

Close a HID device.

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_close, defined at SDL3/SDL_hidapi.h 473:33

Since: 3.2.0

Get The Manufacturer String from a HID device.

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_manufacturer_string, defined at SDL3/SDL_hidapi.h 486:33

Since: 3.2.0

Get The Product String from a HID device.

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_product_string, defined at SDL3/SDL_hidapi.h 499:33

Since: 3.2.0

Get The Serial Number String from a HID device.

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_serial_number_string, defined at SDL3/SDL_hidapi.h 512:33

Since: 3.2.0

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

Returns

0 on success or a negative error code on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_indexed_string, defined at SDL3/SDL_hidapi.h 526:33

Since: 3.2.0

Get the device info from a HID device.

Returns

a pointer to the SDL_hid_device_info for this hid_device or NULL on failure; call SDL_GetError() for more information. This struct is valid until the device is closed with SDL_hid_close().

C declaration

SDL_hid_get_device_info, defined at SDL3/SDL_hidapi.h 538:51

Since: 3.2.0

Get a report descriptor from a HID device.

User has to provide a preallocated buffer where descriptor will be copied to. The recommended size for a preallocated buffer is 4096 bytes.

Returns

the number of bytes actually copied or -1 on failure; call SDL_GetError() for more information.

C declaration

SDL_hid_get_report_descriptor, defined at SDL3/SDL_hidapi.h 554:33

Since: 3.2.0

Start or stop a BLE scan on iOS and tvOS to pair Steam Controllers.

C declaration

SDL_hid_ble_scan, defined at SDL3/SDL_hidapi.h 563:34

Since: 3.2.0