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      1 /*
      2  * Public libusbx header file
      3  * Copyright  2001 Johannes Erdfelt <johannes (at) erdfelt.com>
      4  * Copyright  2007-2008 Daniel Drake <dsd (at) gentoo.org>
      5  * Copyright  2012 Pete Batard <pete (at) akeo.ie>
      6  * Copyright  2012 Nathan Hjelm <hjelmn (at) cs.unm.edu>
      7  * For more information, please visit: http://libusbx.org
      8  *
      9  * This library is free software; you can redistribute it and/or
     10  * modify it under the terms of the GNU Lesser General Public
     11  * License as published by the Free Software Foundation; either
     12  * version 2.1 of the License, or (at your option) any later version.
     13  *
     14  * This library is distributed in the hope that it will be useful,
     15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     17  * Lesser General Public License for more details.
     18  *
     19  * You should have received a copy of the GNU Lesser General Public
     20  * License along with this library; if not, write to the Free Software
     21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
     22  */
     23 
     24 #ifndef LIBUSB_H
     25 #define LIBUSB_H
     26 
     27 #ifdef _MSC_VER
     28 // Disable warning 4200 for [0].
     29 #pragma warning(push)
     30 #pragma warning(disable: 4200)
     31 #endif
     32 
     33 #ifdef _MSC_VER
     34 /* on MS environments, the inline keyword is available in C++ only */
     35 #if !defined(__cplusplus)
     36 #define inline __inline
     37 #endif
     38 /* ssize_t is also not available (copy/paste from MinGW) */
     39 #ifndef _SSIZE_T_DEFINED
     40 #define _SSIZE_T_DEFINED
     41 #undef ssize_t
     42 #ifdef _WIN64
     43   typedef __int64 ssize_t;
     44 #else
     45   typedef int ssize_t;
     46 #endif /* _WIN64 */
     47 #endif /* _SSIZE_T_DEFINED */
     48 #endif /* _MSC_VER */
     49 
     50 /* stdint.h is not available on older MSVC */
     51 #if defined(_MSC_VER) && (_MSC_VER < 1600) && (!defined(_STDINT)) && (!defined(_STDINT_H))
     52 typedef unsigned __int8   uint8_t;
     53 typedef unsigned __int16  uint16_t;
     54 typedef unsigned __int32  uint32_t;
     55 #else
     56 #include <stdint.h>
     57 #endif
     58 
     59 #if !defined(_WIN32_WCE)
     60 #include <sys/types.h>
     61 #endif
     62 
     63 #if defined(__linux) || defined(__APPLE__) || defined(__CYGWIN__)
     64 #include <sys/time.h>
     65 #endif
     66 
     67 #include <time.h>
     68 #include <limits.h>
     69 
     70 /* 'interface' might be defined as a macro on Windows, so we need to
     71  * undefine it so as not to break the current libusbx API, because
     72  * libusb_config_descriptor has an 'interface' member
     73  * As this can be problematic if you include windows.h after libusb.h
     74  * in your sources, we force windows.h to be included first. */
     75 #if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
     76 #include <windows.h>
     77 #if defined(interface)
     78 #undef interface
     79 #endif
     80 #if !defined(__CYGWIN__)
     81 #include <winsock.h>
     82 #endif
     83 #endif
     84 
     85 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
     86 #define LIBUSB_DEPRECATED_FOR(f) \
     87   __attribute__((deprecated("Use " #f " instead")))
     88 #else
     89 #define LIBUSB_DEPRECATED_FOR(f)
     90 #endif /* __GNUC__ */
     91 
     92 /** \def LIBUSB_CALL
     93  * \ingroup misc
     94  * libusbx's Windows calling convention.
     95  *
     96  * Under Windows, the selection of available compilers and configurations
     97  * means that, unlike other platforms, there is not <em>one true calling
     98  * convention</em> (calling convention: the manner in which parameters are
     99  * passed to funcions in the generated assembly code).
    100  *
    101  * Matching the Windows API itself, libusbx uses the WINAPI convention (which
    102  * translates to the <tt>stdcall</tt> convention) and guarantees that the
    103  * library is compiled in this way. The public header file also includes
    104  * appropriate annotations so that your own software will use the right
    105  * convention, even if another convention is being used by default within
    106  * your codebase.
    107  *
    108  * The one consideration that you must apply in your software is to mark
    109  * all functions which you use as libusbx callbacks with this LIBUSB_CALL
    110  * annotation, so that they too get compiled for the correct calling
    111  * convention.
    112  *
    113  * On non-Windows operating systems, this macro is defined as nothing. This
    114  * means that you can apply it to your code without worrying about
    115  * cross-platform compatibility.
    116  */
    117 /* LIBUSB_CALL must be defined on both definition and declaration of libusbx
    118  * functions. You'd think that declaration would be enough, but cygwin will
    119  * complain about conflicting types unless both are marked this way.
    120  * The placement of this macro is important too; it must appear after the
    121  * return type, before the function name. See internal documentation for
    122  * API_EXPORTED.
    123  */
    124 #if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
    125 #define LIBUSB_CALL WINAPI
    126 #else
    127 #define LIBUSB_CALL
    128 #endif
    129 
    130 /** \def LIBUSBX_API_VERSION
    131  * \ingroup misc
    132  * libusbx's API version.
    133  *
    134  * Since version 1.0.13, to help with feature detection, libusbx defines
    135  * a LIBUSBX_API_VERSION macro that gets increased every time there is a
    136  * significant change to the API, such as the introduction of a new call,
    137  * the definition of a new macro/enum member, or any other element that
    138  * libusbx applications may want to detect at compilation time.
    139  *
    140  * The macro is typically used in an application as follows:
    141  * \code
    142  * #if defined(LIBUSBX_API_VERSION) && (LIBUSBX_API_VERSION >= 0x01001234)
    143  * // Use one of the newer features from the libusbx API
    144  * #endif
    145  * \endcode
    146  *
    147  * Another feature of LIBUSBX_API_VERSION is that it can be used to detect
    148  * whether you are compiling against the libusb or the libusbx library.
    149  *
    150  * Internally, LIBUSBX_API_VERSION is defined as follows:
    151  * (libusbx major << 24) | (libusbx minor << 16) | (16 bit incremental)
    152  */
    153 #define LIBUSBX_API_VERSION 0x01000102
    154 
    155 #ifdef __cplusplus
    156 extern "C" {
    157 #endif
    158 
    159 /** \def libusb_cpu_to_le16
    160  * \ingroup misc
    161  * Convert a 16-bit value from host-endian to little-endian format. On
    162  * little endian systems, this function does nothing. On big endian systems,
    163  * the bytes are swapped.
    164  * \param x the host-endian value to convert
    165  * \returns the value in little-endian byte order
    166  */
    167 static inline uint16_t libusb_cpu_to_le16(const uint16_t x)
    168 {
    169 	union {
    170 		uint8_t  b8[2];
    171 		uint16_t b16;
    172 	} _tmp;
    173 	_tmp.b8[1] = (uint8_t) (x >> 8);
    174 	_tmp.b8[0] = (uint8_t) (x & 0xff);
    175 	return _tmp.b16;
    176 }
    177 
    178 /** \def libusb_le16_to_cpu
    179  * \ingroup misc
    180  * Convert a 16-bit value from little-endian to host-endian format. On
    181  * little endian systems, this function does nothing. On big endian systems,
    182  * the bytes are swapped.
    183  * \param x the little-endian value to convert
    184  * \returns the value in host-endian byte order
    185  */
    186 #define libusb_le16_to_cpu libusb_cpu_to_le16
    187 
    188 /* standard USB stuff */
    189 
    190 /** \ingroup desc
    191  * Device and/or Interface Class codes */
    192 enum libusb_class_code {
    193 	/** In the context of a \ref libusb_device_descriptor "device descriptor",
    194 	 * this bDeviceClass value indicates that each interface specifies its
    195 	 * own class information and all interfaces operate independently.
    196 	 */
    197 	LIBUSB_CLASS_PER_INTERFACE = 0,
    198 
    199 	/** Audio class */
    200 	LIBUSB_CLASS_AUDIO = 1,
    201 
    202 	/** Communications class */
    203 	LIBUSB_CLASS_COMM = 2,
    204 
    205 	/** Human Interface Device class */
    206 	LIBUSB_CLASS_HID = 3,
    207 
    208 	/** Physical */
    209 	LIBUSB_CLASS_PHYSICAL = 5,
    210 
    211 	/** Printer class */
    212 	LIBUSB_CLASS_PRINTER = 7,
    213 
    214 	/** Image class */
    215 	LIBUSB_CLASS_PTP = 6, /* legacy name from libusb-0.1 usb.h */
    216 	LIBUSB_CLASS_IMAGE = 6,
    217 
    218 	/** Mass storage class */
    219 	LIBUSB_CLASS_MASS_STORAGE = 8,
    220 
    221 	/** Hub class */
    222 	LIBUSB_CLASS_HUB = 9,
    223 
    224 	/** Data class */
    225 	LIBUSB_CLASS_DATA = 10,
    226 
    227 	/** Smart Card */
    228 	LIBUSB_CLASS_SMART_CARD = 0x0b,
    229 
    230 	/** Content Security */
    231 	LIBUSB_CLASS_CONTENT_SECURITY = 0x0d,
    232 
    233 	/** Video */
    234 	LIBUSB_CLASS_VIDEO = 0x0e,
    235 
    236 	/** Personal Healthcare */
    237 	LIBUSB_CLASS_PERSONAL_HEALTHCARE = 0x0f,
    238 
    239 	/** Diagnostic Device */
    240 	LIBUSB_CLASS_DIAGNOSTIC_DEVICE = 0xdc,
    241 
    242 	/** Wireless class */
    243 	LIBUSB_CLASS_WIRELESS = 0xe0,
    244 
    245 	/** Application class */
    246 	LIBUSB_CLASS_APPLICATION = 0xfe,
    247 
    248 	/** Class is vendor-specific */
    249 	LIBUSB_CLASS_VENDOR_SPEC = 0xff
    250 };
    251 
    252 /** \ingroup desc
    253  * Descriptor types as defined by the USB specification. */
    254 enum libusb_descriptor_type {
    255 	/** Device descriptor. See libusb_device_descriptor. */
    256 	LIBUSB_DT_DEVICE = 0x01,
    257 
    258 	/** Configuration descriptor. See libusb_config_descriptor. */
    259 	LIBUSB_DT_CONFIG = 0x02,
    260 
    261 	/** String descriptor */
    262 	LIBUSB_DT_STRING = 0x03,
    263 
    264 	/** Interface descriptor. See libusb_interface_descriptor. */
    265 	LIBUSB_DT_INTERFACE = 0x04,
    266 
    267 	/** Endpoint descriptor. See libusb_endpoint_descriptor. */
    268 	LIBUSB_DT_ENDPOINT = 0x05,
    269 
    270 	/** BOS descriptor */
    271 	LIBUSB_DT_BOS = 0x0f,
    272 
    273 	/** Device Capability descriptor */
    274 	LIBUSB_DT_DEVICE_CAPABILITY = 0x10,
    275 
    276 	/** HID descriptor */
    277 	LIBUSB_DT_HID = 0x21,
    278 
    279 	/** HID report descriptor */
    280 	LIBUSB_DT_REPORT = 0x22,
    281 
    282 	/** Physical descriptor */
    283 	LIBUSB_DT_PHYSICAL = 0x23,
    284 
    285 	/** Hub descriptor */
    286 	LIBUSB_DT_HUB = 0x29,
    287 
    288 	/** SuperSpeed Hub descriptor */
    289 	LIBUSB_DT_SUPERSPEED_HUB = 0x2a,
    290 
    291 	/** SuperSpeed Endpoint Companion descriptor */
    292 	LIBUSB_DT_SS_ENDPOINT_COMPANION = 0x30
    293 };
    294 
    295 /* Descriptor sizes per descriptor type */
    296 #define LIBUSB_DT_DEVICE_SIZE			18
    297 #define LIBUSB_DT_CONFIG_SIZE			9
    298 #define LIBUSB_DT_INTERFACE_SIZE		9
    299 #define LIBUSB_DT_ENDPOINT_SIZE			7
    300 #define LIBUSB_DT_ENDPOINT_AUDIO_SIZE		9	/* Audio extension */
    301 #define LIBUSB_DT_HUB_NONVAR_SIZE		7
    302 #define LIBUSB_DT_SS_ENDPOINT_COMPANION_SIZE	6
    303 #define LIBUSB_DT_BOS_SIZE			5
    304 #define LIBUSB_DT_DEVICE_CAPABILITY_SIZE	3
    305 
    306 /* BOS descriptor sizes */
    307 #define LIBUSB_BT_USB_2_0_EXTENSION_SIZE	7
    308 #define LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE	10
    309 #define LIBUSB_BT_CONTAINER_ID_SIZE		20
    310 
    311 /* We unwrap the BOS => define its max size */
    312 #define LIBUSB_DT_BOS_MAX_SIZE		((LIBUSB_DT_BOS_SIZE)     +\
    313 					(LIBUSB_BT_USB_2_0_EXTENSION_SIZE)       +\
    314 					(LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE) +\
    315 					(LIBUSB_BT_CONTAINER_ID_SIZE))
    316 
    317 #define LIBUSB_ENDPOINT_ADDRESS_MASK	0x0f    /* in bEndpointAddress */
    318 #define LIBUSB_ENDPOINT_DIR_MASK		0x80
    319 
    320 /** \ingroup desc
    321  * Endpoint direction. Values for bit 7 of the
    322  * \ref libusb_endpoint_descriptor::bEndpointAddress "endpoint address" scheme.
    323  */
    324 enum libusb_endpoint_direction {
    325 	/** In: device-to-host */
    326 	LIBUSB_ENDPOINT_IN = 0x80,
    327 
    328 	/** Out: host-to-device */
    329 	LIBUSB_ENDPOINT_OUT = 0x00
    330 };
    331 
    332 #define LIBUSB_TRANSFER_TYPE_MASK			0x03    /* in bmAttributes */
    333 
    334 /** \ingroup desc
    335  * Endpoint transfer type. Values for bits 0:1 of the
    336  * \ref libusb_endpoint_descriptor::bmAttributes "endpoint attributes" field.
    337  */
    338 enum libusb_transfer_type {
    339 	/** Control endpoint */
    340 	LIBUSB_TRANSFER_TYPE_CONTROL = 0,
    341 
    342 	/** Isochronous endpoint */
    343 	LIBUSB_TRANSFER_TYPE_ISOCHRONOUS = 1,
    344 
    345 	/** Bulk endpoint */
    346 	LIBUSB_TRANSFER_TYPE_BULK = 2,
    347 
    348 	/** Interrupt endpoint */
    349 	LIBUSB_TRANSFER_TYPE_INTERRUPT = 3
    350 };
    351 
    352 /** \ingroup misc
    353  * Standard requests, as defined in table 9-5 of the USB 3.0 specifications */
    354 enum libusb_standard_request {
    355 	/** Request status of the specific recipient */
    356 	LIBUSB_REQUEST_GET_STATUS = 0x00,
    357 
    358 	/** Clear or disable a specific feature */
    359 	LIBUSB_REQUEST_CLEAR_FEATURE = 0x01,
    360 
    361 	/* 0x02 is reserved */
    362 
    363 	/** Set or enable a specific feature */
    364 	LIBUSB_REQUEST_SET_FEATURE = 0x03,
    365 
    366 	/* 0x04 is reserved */
    367 
    368 	/** Set device address for all future accesses */
    369 	LIBUSB_REQUEST_SET_ADDRESS = 0x05,
    370 
    371 	/** Get the specified descriptor */
    372 	LIBUSB_REQUEST_GET_DESCRIPTOR = 0x06,
    373 
    374 	/** Used to update existing descriptors or add new descriptors */
    375 	LIBUSB_REQUEST_SET_DESCRIPTOR = 0x07,
    376 
    377 	/** Get the current device configuration value */
    378 	LIBUSB_REQUEST_GET_CONFIGURATION = 0x08,
    379 
    380 	/** Set device configuration */
    381 	LIBUSB_REQUEST_SET_CONFIGURATION = 0x09,
    382 
    383 	/** Return the selected alternate setting for the specified interface */
    384 	LIBUSB_REQUEST_GET_INTERFACE = 0x0A,
    385 
    386 	/** Select an alternate interface for the specified interface */
    387 	LIBUSB_REQUEST_SET_INTERFACE = 0x0B,
    388 
    389 	/** Set then report an endpoint's synchronization frame */
    390 	LIBUSB_REQUEST_SYNCH_FRAME = 0x0C,
    391 
    392 	/** Sets both the U1 and U2 Exit Latency */
    393 	LIBUSB_REQUEST_SET_SEL = 0x30,
    394 
    395 	/** Delay from the time a host transmits a packet to the time it is
    396 	  * received by the device. */
    397 	LIBUSB_SET_ISOCH_DELAY = 0x31,
    398 };
    399 
    400 /** \ingroup misc
    401  * Request type bits of the
    402  * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
    403  * transfers. */
    404 enum libusb_request_type {
    405 	/** Standard */
    406 	LIBUSB_REQUEST_TYPE_STANDARD = (0x00 << 5),
    407 
    408 	/** Class */
    409 	LIBUSB_REQUEST_TYPE_CLASS = (0x01 << 5),
    410 
    411 	/** Vendor */
    412 	LIBUSB_REQUEST_TYPE_VENDOR = (0x02 << 5),
    413 
    414 	/** Reserved */
    415 	LIBUSB_REQUEST_TYPE_RESERVED = (0x03 << 5)
    416 };
    417 
    418 /** \ingroup misc
    419  * Recipient bits of the
    420  * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
    421  * transfers. Values 4 through 31 are reserved. */
    422 enum libusb_request_recipient {
    423 	/** Device */
    424 	LIBUSB_RECIPIENT_DEVICE = 0x00,
    425 
    426 	/** Interface */
    427 	LIBUSB_RECIPIENT_INTERFACE = 0x01,
    428 
    429 	/** Endpoint */
    430 	LIBUSB_RECIPIENT_ENDPOINT = 0x02,
    431 
    432 	/** Other */
    433 	LIBUSB_RECIPIENT_OTHER = 0x03,
    434 };
    435 
    436 #define LIBUSB_ISO_SYNC_TYPE_MASK		0x0C
    437 
    438 /** \ingroup desc
    439  * Synchronization type for isochronous endpoints. Values for bits 2:3 of the
    440  * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
    441  * libusb_endpoint_descriptor.
    442  */
    443 enum libusb_iso_sync_type {
    444 	/** No synchronization */
    445 	LIBUSB_ISO_SYNC_TYPE_NONE = 0,
    446 
    447 	/** Asynchronous */
    448 	LIBUSB_ISO_SYNC_TYPE_ASYNC = 1,
    449 
    450 	/** Adaptive */
    451 	LIBUSB_ISO_SYNC_TYPE_ADAPTIVE = 2,
    452 
    453 	/** Synchronous */
    454 	LIBUSB_ISO_SYNC_TYPE_SYNC = 3
    455 };
    456 
    457 #define LIBUSB_ISO_USAGE_TYPE_MASK 0x30
    458 
    459 /** \ingroup desc
    460  * Usage type for isochronous endpoints. Values for bits 4:5 of the
    461  * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
    462  * libusb_endpoint_descriptor.
    463  */
    464 enum libusb_iso_usage_type {
    465 	/** Data endpoint */
    466 	LIBUSB_ISO_USAGE_TYPE_DATA = 0,
    467 
    468 	/** Feedback endpoint */
    469 	LIBUSB_ISO_USAGE_TYPE_FEEDBACK = 1,
    470 
    471 	/** Implicit feedback Data endpoint */
    472 	LIBUSB_ISO_USAGE_TYPE_IMPLICIT = 2,
    473 };
    474 
    475 /** \ingroup desc
    476  * A structure representing the standard USB device descriptor. This
    477  * descriptor is documented in section 9.6.1 of the USB 3.0 specification.
    478  * All multiple-byte fields are represented in host-endian format.
    479  */
    480 struct libusb_device_descriptor {
    481 	/** Size of this descriptor (in bytes) */
    482 	uint8_t  bLength;
    483 
    484 	/** Descriptor type. Will have value
    485 	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE LIBUSB_DT_DEVICE in this
    486 	 * context. */
    487 	uint8_t  bDescriptorType;
    488 
    489 	/** USB specification release number in binary-coded decimal. A value of
    490 	 * 0x0200 indicates USB 2.0, 0x0110 indicates USB 1.1, etc. */
    491 	uint16_t bcdUSB;
    492 
    493 	/** USB-IF class code for the device. See \ref libusb_class_code. */
    494 	uint8_t  bDeviceClass;
    495 
    496 	/** USB-IF subclass code for the device, qualified by the bDeviceClass
    497 	 * value */
    498 	uint8_t  bDeviceSubClass;
    499 
    500 	/** USB-IF protocol code for the device, qualified by the bDeviceClass and
    501 	 * bDeviceSubClass values */
    502 	uint8_t  bDeviceProtocol;
    503 
    504 	/** Maximum packet size for endpoint 0 */
    505 	uint8_t  bMaxPacketSize0;
    506 
    507 	/** USB-IF vendor ID */
    508 	uint16_t idVendor;
    509 
    510 	/** USB-IF product ID */
    511 	uint16_t idProduct;
    512 
    513 	/** Device release number in binary-coded decimal */
    514 	uint16_t bcdDevice;
    515 
    516 	/** Index of string descriptor describing manufacturer */
    517 	uint8_t  iManufacturer;
    518 
    519 	/** Index of string descriptor describing product */
    520 	uint8_t  iProduct;
    521 
    522 	/** Index of string descriptor containing device serial number */
    523 	uint8_t  iSerialNumber;
    524 
    525 	/** Number of possible configurations */
    526 	uint8_t  bNumConfigurations;
    527 };
    528 
    529 /** \ingroup desc
    530  * A structure representing the standard USB endpoint descriptor. This
    531  * descriptor is documented in section 9.6.6 of the USB 3.0 specification.
    532  * All multiple-byte fields are represented in host-endian format.
    533  */
    534 struct libusb_endpoint_descriptor {
    535 	/** Size of this descriptor (in bytes) */
    536 	uint8_t  bLength;
    537 
    538 	/** Descriptor type. Will have value
    539 	 * \ref libusb_descriptor_type::LIBUSB_DT_ENDPOINT LIBUSB_DT_ENDPOINT in
    540 	 * this context. */
    541 	uint8_t  bDescriptorType;
    542 
    543 	/** The address of the endpoint described by this descriptor. Bits 0:3 are
    544 	 * the endpoint number. Bits 4:6 are reserved. Bit 7 indicates direction,
    545 	 * see \ref libusb_endpoint_direction.
    546 	 */
    547 	uint8_t  bEndpointAddress;
    548 
    549 	/** Attributes which apply to the endpoint when it is configured using
    550 	 * the bConfigurationValue. Bits 0:1 determine the transfer type and
    551 	 * correspond to \ref libusb_transfer_type. Bits 2:3 are only used for
    552 	 * isochronous endpoints and correspond to \ref libusb_iso_sync_type.
    553 	 * Bits 4:5 are also only used for isochronous endpoints and correspond to
    554 	 * \ref libusb_iso_usage_type. Bits 6:7 are reserved.
    555 	 */
    556 	uint8_t  bmAttributes;
    557 
    558 	/** Maximum packet size this endpoint is capable of sending/receiving. */
    559 	uint16_t wMaxPacketSize;
    560 
    561 	/** Interval for polling endpoint for data transfers. */
    562 	uint8_t  bInterval;
    563 
    564 	/** For audio devices only: the rate at which synchronization feedback
    565 	 * is provided. */
    566 	uint8_t  bRefresh;
    567 
    568 	/** For audio devices only: the address if the synch endpoint */
    569 	uint8_t  bSynchAddress;
    570 
    571 	/** Extra descriptors. If libusbx encounters unknown endpoint descriptors,
    572 	 * it will store them here, should you wish to parse them. */
    573 	const unsigned char *extra;
    574 
    575 	/** Length of the extra descriptors, in bytes. */
    576 	int extra_length;
    577 };
    578 
    579 /** \ingroup desc
    580  * A structure representing the standard USB interface descriptor. This
    581  * descriptor is documented in section 9.6.5 of the USB 3.0 specification.
    582  * All multiple-byte fields are represented in host-endian format.
    583  */
    584 struct libusb_interface_descriptor {
    585 	/** Size of this descriptor (in bytes) */
    586 	uint8_t  bLength;
    587 
    588 	/** Descriptor type. Will have value
    589 	 * \ref libusb_descriptor_type::LIBUSB_DT_INTERFACE LIBUSB_DT_INTERFACE
    590 	 * in this context. */
    591 	uint8_t  bDescriptorType;
    592 
    593 	/** Number of this interface */
    594 	uint8_t  bInterfaceNumber;
    595 
    596 	/** Value used to select this alternate setting for this interface */
    597 	uint8_t  bAlternateSetting;
    598 
    599 	/** Number of endpoints used by this interface (excluding the control
    600 	 * endpoint). */
    601 	uint8_t  bNumEndpoints;
    602 
    603 	/** USB-IF class code for this interface. See \ref libusb_class_code. */
    604 	uint8_t  bInterfaceClass;
    605 
    606 	/** USB-IF subclass code for this interface, qualified by the
    607 	 * bInterfaceClass value */
    608 	uint8_t  bInterfaceSubClass;
    609 
    610 	/** USB-IF protocol code for this interface, qualified by the
    611 	 * bInterfaceClass and bInterfaceSubClass values */
    612 	uint8_t  bInterfaceProtocol;
    613 
    614 	/** Index of string descriptor describing this interface */
    615 	uint8_t  iInterface;
    616 
    617 	/** Array of endpoint descriptors. This length of this array is determined
    618 	 * by the bNumEndpoints field. */
    619 	const struct libusb_endpoint_descriptor *endpoint;
    620 
    621 	/** Extra descriptors. If libusbx encounters unknown interface descriptors,
    622 	 * it will store them here, should you wish to parse them. */
    623 	const unsigned char *extra;
    624 
    625 	/** Length of the extra descriptors, in bytes. */
    626 	int extra_length;
    627 };
    628 
    629 /** \ingroup desc
    630  * A collection of alternate settings for a particular USB interface.
    631  */
    632 struct libusb_interface {
    633 	/** Array of interface descriptors. The length of this array is determined
    634 	 * by the num_altsetting field. */
    635 	const struct libusb_interface_descriptor *altsetting;
    636 
    637 	/** The number of alternate settings that belong to this interface */
    638 	int num_altsetting;
    639 };
    640 
    641 /** \ingroup desc
    642  * A structure representing the standard USB configuration descriptor. This
    643  * descriptor is documented in section 9.6.3 of the USB 3.0 specification.
    644  * All multiple-byte fields are represented in host-endian format.
    645  */
    646 struct libusb_config_descriptor {
    647 	/** Size of this descriptor (in bytes) */
    648 	uint8_t  bLength;
    649 
    650 	/** Descriptor type. Will have value
    651 	 * \ref libusb_descriptor_type::LIBUSB_DT_CONFIG LIBUSB_DT_CONFIG
    652 	 * in this context. */
    653 	uint8_t  bDescriptorType;
    654 
    655 	/** Total length of data returned for this configuration */
    656 	uint16_t wTotalLength;
    657 
    658 	/** Number of interfaces supported by this configuration */
    659 	uint8_t  bNumInterfaces;
    660 
    661 	/** Identifier value for this configuration */
    662 	uint8_t  bConfigurationValue;
    663 
    664 	/** Index of string descriptor describing this configuration */
    665 	uint8_t  iConfiguration;
    666 
    667 	/** Configuration characteristics */
    668 	uint8_t  bmAttributes;
    669 
    670 	/** Maximum power consumption of the USB device from this bus in this
    671 	 * configuration when the device is fully opreation. Expressed in units
    672 	 * of 2 mA. */
    673 	uint8_t  MaxPower;
    674 
    675 	/** Array of interfaces supported by this configuration. The length of
    676 	 * this array is determined by the bNumInterfaces field. */
    677 	const struct libusb_interface *interface;
    678 
    679 	/** Extra descriptors. If libusbx encounters unknown configuration
    680 	 * descriptors, it will store them here, should you wish to parse them. */
    681 	const unsigned char *extra;
    682 
    683 	/** Length of the extra descriptors, in bytes. */
    684 	int extra_length;
    685 };
    686 
    687 /** \ingroup desc
    688  * A structure representing the superspeed endpoint companion
    689  * descriptor. This descriptor is documented in section 9.6.7 of
    690  * the USB 3.0 specification. All multiple-byte fields are represented in
    691  * host-endian format.
    692  */
    693 struct libusb_ss_endpoint_companion_descriptor {
    694 
    695 	/** Size of this descriptor (in bytes) */
    696 	uint8_t  bLength;
    697 
    698 	/** Descriptor type. Will have value
    699 	 * \ref libusb_descriptor_type::LIBUSB_DT_SS_ENDPOINT_COMPANION in
    700 	 * this context. */
    701 	uint8_t  bDescriptorType;
    702 
    703 
    704 	/** The maximum number of packets the endpoint can send or
    705 	 *  recieve as part of a burst. */
    706 	uint8_t  bMaxBurst;
    707 
    708 	/** In bulk EP:	bits 4:0 represents the	maximum	number of
    709 	 *  streams the	EP supports. In	isochronous EP:	bits 1:0
    710 	 *  represents the Mult	- a zero based value that determines
    711 	 *  the	maximum	number of packets within a service interval  */
    712 	uint8_t  bmAttributes;
    713 
    714 	/** The	total number of bytes this EP will transfer every
    715 	 *  service interval. valid only for periodic EPs. */
    716 	uint16_t wBytesPerInterval;
    717 };
    718 
    719 /** \ingroup desc
    720  * A generic representation of a BOS Device Capability descriptor. It is
    721  * advised to check bDevCapabilityType and call the matching
    722  * libusb_get_*_descriptor function to get a structure fully matching the type.
    723  */
    724 struct libusb_bos_dev_capability_descriptor {
    725 	/** Size of this descriptor (in bytes) */
    726 	uint8_t bLength;
    727 	/** Descriptor type. Will have value
    728 	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
    729 	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
    730 	uint8_t bDescriptorType;
    731 	/** Device Capability type */
    732 	uint8_t bDevCapabilityType;
    733 	/** Device Capability data (bLength - 3 bytes) */
    734 	uint8_t dev_capability_data
    735 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
    736 	[] /* valid C99 code */
    737 #else
    738 	[0] /* non-standard, but usually working code */
    739 #endif
    740 	;
    741 };
    742 
    743 /** \ingroup desc
    744  * A structure representing the Binary Device Object Store (BOS) descriptor.
    745  * This descriptor is documented in section 9.6.2 of the USB 3.0 specification.
    746  * All multiple-byte fields are represented in host-endian format.
    747  */
    748 struct libusb_bos_descriptor {
    749 	/** Size of this descriptor (in bytes) */
    750 	uint8_t  bLength;
    751 
    752 	/** Descriptor type. Will have value
    753 	 * \ref libusb_descriptor_type::LIBUSB_DT_BOS LIBUSB_DT_BOS
    754 	 * in this context. */
    755 	uint8_t  bDescriptorType;
    756 
    757 	/** Length of this descriptor and all of its sub descriptors */
    758 	uint16_t wTotalLength;
    759 
    760 	/** The number of separate device capability descriptors in
    761 	 * the BOS */
    762 	uint8_t  bNumDeviceCaps;
    763 
    764 	/** bNumDeviceCap Device Capability Descriptors */
    765 	struct libusb_bos_dev_capability_descriptor *dev_capability
    766 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
    767 	[] /* valid C99 code */
    768 #else
    769 	[0] /* non-standard, but usually working code */
    770 #endif
    771 	;
    772 };
    773 
    774 /** \ingroup desc
    775  * A structure representing the USB 2.0 Extension descriptor
    776  * This descriptor is documented in section 9.6.2.1 of the USB 3.0 specification.
    777  * All multiple-byte fields are represented in host-endian format.
    778  */
    779 struct libusb_usb_2_0_extension_descriptor {
    780 	/** Size of this descriptor (in bytes) */
    781 	uint8_t  bLength;
    782 
    783 	/** Descriptor type. Will have value
    784 	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
    785 	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
    786 	uint8_t  bDescriptorType;
    787 
    788 	/** Capability type. Will have value
    789 	 * \ref libusb_capability_type::LIBUSB_BT_USB_2_0_EXTENSION
    790 	 * LIBUSB_BT_USB_2_0_EXTENSION in this context. */
    791 	uint8_t  bDevCapabilityType;
    792 
    793 	/** Bitmap encoding of supported device level features.
    794 	 * A value of one in a bit location indicates a feature is
    795 	 * supported; a value of zero indicates it is not supported.
    796 	 * See \ref libusb_usb_2_0_extension_attributes. */
    797 	uint32_t  bmAttributes;
    798 };
    799 
    800 /** \ingroup desc
    801  * A structure representing the SuperSpeed USB Device Capability descriptor
    802  * This descriptor is documented in section 9.6.2.2 of the USB 3.0 specification.
    803  * All multiple-byte fields are represented in host-endian format.
    804  */
    805 struct libusb_ss_usb_device_capability_descriptor {
    806 	/** Size of this descriptor (in bytes) */
    807 	uint8_t  bLength;
    808 
    809 	/** Descriptor type. Will have value
    810 	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
    811 	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
    812 	uint8_t  bDescriptorType;
    813 
    814 	/** Capability type. Will have value
    815 	 * \ref libusb_capability_type::LIBUSB_BT_SS_USB_DEVICE_CAPABILITY
    816 	 * LIBUSB_BT_SS_USB_DEVICE_CAPABILITY in this context. */
    817 	uint8_t  bDevCapabilityType;
    818 
    819 	/** Bitmap encoding of supported device level features.
    820 	 * A value of one in a bit location indicates a feature is
    821 	 * supported; a value of zero indicates it is not supported.
    822 	 * See \ref libusb_ss_usb_device_capability_attributes. */
    823 	uint8_t  bmAttributes;
    824 
    825 	/** Bitmap encoding of the speed supported by this device when
    826 	 * operating in SuperSpeed mode. See \ref libusb_supported_speed. */
    827 	uint16_t wSpeedSupported;
    828 
    829 	/** The lowest speed at which all the functionality supported
    830 	 * by the device is available to the user. For example if the
    831 	 * device supports all its functionality when connected at
    832 	 * full speed and above then it sets this value to 1. */
    833 	uint8_t  bFunctionalitySupport;
    834 
    835 	/** U1 Device Exit Latency. */
    836 	uint8_t  bU1DevExitLat;
    837 
    838 	/** U2 Device Exit Latency. */
    839 	uint16_t bU2DevExitLat;
    840 };
    841 
    842 /** \ingroup desc
    843  * A structure representing the Container ID descriptor.
    844  * This descriptor is documented in section 9.6.2.3 of the USB 3.0 specification.
    845  * All multiple-byte fields, except UUIDs, are represented in host-endian format.
    846  */
    847 struct libusb_container_id_descriptor {
    848 	/** Size of this descriptor (in bytes) */
    849 	uint8_t  bLength;
    850 
    851 	/** Descriptor type. Will have value
    852 	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
    853 	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
    854 	uint8_t  bDescriptorType;
    855 
    856 	/** Capability type. Will have value
    857 	 * \ref libusb_capability_type::LIBUSB_BT_CONTAINER_ID
    858 	 * LIBUSB_BT_CONTAINER_ID in this context. */
    859 	uint8_t  bDevCapabilityType;
    860 
    861 	/** Reserved field */
    862 	uint8_t bReserved;
    863 
    864 	/** 128 bit UUID */
    865 	uint8_t  ContainerID[16];
    866 };
    867 
    868 /** \ingroup asyncio
    869  * Setup packet for control transfers. */
    870 struct libusb_control_setup {
    871 	/** Request type. Bits 0:4 determine recipient, see
    872 	 * \ref libusb_request_recipient. Bits 5:6 determine type, see
    873 	 * \ref libusb_request_type. Bit 7 determines data transfer direction, see
    874 	 * \ref libusb_endpoint_direction.
    875 	 */
    876 	uint8_t  bmRequestType;
    877 
    878 	/** Request. If the type bits of bmRequestType are equal to
    879 	 * \ref libusb_request_type::LIBUSB_REQUEST_TYPE_STANDARD
    880 	 * "LIBUSB_REQUEST_TYPE_STANDARD" then this field refers to
    881 	 * \ref libusb_standard_request. For other cases, use of this field is
    882 	 * application-specific. */
    883 	uint8_t  bRequest;
    884 
    885 	/** Value. Varies according to request */
    886 	uint16_t wValue;
    887 
    888 	/** Index. Varies according to request, typically used to pass an index
    889 	 * or offset */
    890 	uint16_t wIndex;
    891 
    892 	/** Number of bytes to transfer */
    893 	uint16_t wLength;
    894 };
    895 
    896 #define LIBUSB_CONTROL_SETUP_SIZE (sizeof(struct libusb_control_setup))
    897 
    898 /* libusbx */
    899 
    900 struct libusb_context;
    901 struct libusb_device;
    902 struct libusb_device_handle;
    903 struct libusb_hotplug_callback;
    904 
    905 /** \ingroup lib
    906  * Structure providing the version of the libusbx runtime
    907  */
    908 struct libusb_version {
    909 	/** Library major version. */
    910 	const uint16_t major;
    911 
    912 	/** Library minor version. */
    913 	const uint16_t minor;
    914 
    915 	/** Library micro version. */
    916 	const uint16_t micro;
    917 
    918 	/** Library nano version. */
    919 	const uint16_t nano;
    920 
    921 	/** Library release candidate suffix string, e.g. "-rc4". */
    922 	const char *rc;
    923 
    924 	/** For ABI compatibility only. */
    925 	const char* describe;
    926 };
    927 
    928 /** \ingroup lib
    929  * Structure representing a libusbx session. The concept of individual libusbx
    930  * sessions allows for your program to use two libraries (or dynamically
    931  * load two modules) which both independently use libusb. This will prevent
    932  * interference between the individual libusbx users - for example
    933  * libusb_set_debug() will not affect the other user of the library, and
    934  * libusb_exit() will not destroy resources that the other user is still
    935  * using.
    936  *
    937  * Sessions are created by libusb_init() and destroyed through libusb_exit().
    938  * If your application is guaranteed to only ever include a single libusbx
    939  * user (i.e. you), you do not have to worry about contexts: pass NULL in
    940  * every function call where a context is required. The default context
    941  * will be used.
    942  *
    943  * For more information, see \ref contexts.
    944  */
    945 typedef struct libusb_context libusb_context;
    946 
    947 /** \ingroup dev
    948  * Structure representing a USB device detected on the system. This is an
    949  * opaque type for which you are only ever provided with a pointer, usually
    950  * originating from libusb_get_device_list().
    951  *
    952  * Certain operations can be performed on a device, but in order to do any
    953  * I/O you will have to first obtain a device handle using libusb_open().
    954  *
    955  * Devices are reference counted with libusb_ref_device() and
    956  * libusb_unref_device(), and are freed when the reference count reaches 0.
    957  * New devices presented by libusb_get_device_list() have a reference count of
    958  * 1, and libusb_free_device_list() can optionally decrease the reference count
    959  * on all devices in the list. libusb_open() adds another reference which is
    960  * later destroyed by libusb_close().
    961  */
    962 typedef struct libusb_device libusb_device;
    963 
    964 
    965 /** \ingroup dev
    966  * Structure representing a handle on a USB device. This is an opaque type for
    967  * which you are only ever provided with a pointer, usually originating from
    968  * libusb_open().
    969  *
    970  * A device handle is used to perform I/O and other operations. When finished
    971  * with a device handle, you should call libusb_close().
    972  */
    973 typedef struct libusb_device_handle libusb_device_handle;
    974 
    975 /** \ingroup dev
    976  * Speed codes. Indicates the speed at which the device is operating.
    977  */
    978 enum libusb_speed {
    979 	/** The OS doesn't report or know the device speed. */
    980 	LIBUSB_SPEED_UNKNOWN = 0,
    981 
    982 	/** The device is operating at low speed (1.5MBit/s). */
    983 	LIBUSB_SPEED_LOW = 1,
    984 
    985 	/** The device is operating at full speed (12MBit/s). */
    986 	LIBUSB_SPEED_FULL = 2,
    987 
    988 	/** The device is operating at high speed (480MBit/s). */
    989 	LIBUSB_SPEED_HIGH = 3,
    990 
    991 	/** The device is operating at super speed (5000MBit/s). */
    992 	LIBUSB_SPEED_SUPER = 4,
    993 };
    994 
    995 /** \ingroup dev
    996  * Supported speeds (wSpeedSupported) bitfield. Indicates what
    997  * speeds the device supports.
    998  */
    999 enum libusb_supported_speed {
   1000 	/** Low speed operation supported (1.5MBit/s). */
   1001 	LIBUSB_LOW_SPEED_OPERATION   = 1,
   1002 
   1003 	/** Full speed operation supported (12MBit/s). */
   1004 	LIBUSB_FULL_SPEED_OPERATION  = 2,
   1005 
   1006 	/** High speed operation supported (480MBit/s). */
   1007 	LIBUSB_HIGH_SPEED_OPERATION  = 4,
   1008 
   1009 	/** Superspeed operation supported (5000MBit/s). */
   1010 	LIBUSB_SUPER_SPEED_OPERATION = 8,
   1011 };
   1012 
   1013 /** \ingroup dev
   1014  * Masks for the bits of the
   1015  * \ref libusb_usb_2_0_extension_descriptor::bmAttributes "bmAttributes" field
   1016  * of the USB 2.0 Extension descriptor.
   1017  */
   1018 enum libusb_usb_2_0_extension_attributes {
   1019 	/** Supports Link Power Management (LPM) */
   1020 	LIBUSB_BM_LPM_SUPPORT = 2,
   1021 };
   1022 
   1023 /** \ingroup dev
   1024  * Masks for the bits of the
   1025  * \ref libusb_ss_usb_device_capability_descriptor::bmAttributes "bmAttributes" field
   1026  * field of the SuperSpeed USB Device Capability descriptor.
   1027  */
   1028 enum libusb_ss_usb_device_capability_attributes {
   1029 	/** Supports Latency Tolerance Messages (LTM) */
   1030 	LIBUSB_BM_LTM_SUPPORT = 2,
   1031 };
   1032 
   1033 /** \ingroup dev
   1034  * USB capability types
   1035  */
   1036 enum libusb_bos_type {
   1037 	/** Wireless USB device capability */
   1038 	LIBUSB_BT_WIRELESS_USB_DEVICE_CAPABILITY	= 1,
   1039 
   1040 	/** USB 2.0 extensions */
   1041 	LIBUSB_BT_USB_2_0_EXTENSION			= 2,
   1042 
   1043 	/** SuperSpeed USB device capability */
   1044 	LIBUSB_BT_SS_USB_DEVICE_CAPABILITY		= 3,
   1045 
   1046 	/** Container ID type */
   1047 	LIBUSB_BT_CONTAINER_ID				= 4,
   1048 };
   1049 
   1050 /** \ingroup misc
   1051  * Error codes. Most libusbx functions return 0 on success or one of these
   1052  * codes on failure.
   1053  * You can call libusb_error_name() to retrieve a string representation of an
   1054  * error code or libusb_strerror() to get an end-user suitable description of
   1055  * an error code.
   1056  */
   1057 enum libusb_error {
   1058 	/** Success (no error) */
   1059 	LIBUSB_SUCCESS = 0,
   1060 
   1061 	/** Input/output error */
   1062 	LIBUSB_ERROR_IO = -1,
   1063 
   1064 	/** Invalid parameter */
   1065 	LIBUSB_ERROR_INVALID_PARAM = -2,
   1066 
   1067 	/** Access denied (insufficient permissions) */
   1068 	LIBUSB_ERROR_ACCESS = -3,
   1069 
   1070 	/** No such device (it may have been disconnected) */
   1071 	LIBUSB_ERROR_NO_DEVICE = -4,
   1072 
   1073 	/** Entity not found */
   1074 	LIBUSB_ERROR_NOT_FOUND = -5,
   1075 
   1076 	/** Resource busy */
   1077 	LIBUSB_ERROR_BUSY = -6,
   1078 
   1079 	/** Operation timed out */
   1080 	LIBUSB_ERROR_TIMEOUT = -7,
   1081 
   1082 	/** Overflow */
   1083 	LIBUSB_ERROR_OVERFLOW = -8,
   1084 
   1085 	/** Pipe error */
   1086 	LIBUSB_ERROR_PIPE = -9,
   1087 
   1088 	/** System call interrupted (perhaps due to signal) */
   1089 	LIBUSB_ERROR_INTERRUPTED = -10,
   1090 
   1091 	/** Insufficient memory */
   1092 	LIBUSB_ERROR_NO_MEM = -11,
   1093 
   1094 	/** Operation not supported or unimplemented on this platform */
   1095 	LIBUSB_ERROR_NOT_SUPPORTED = -12,
   1096 
   1097 	/* NB: Remember to update LIBUSB_ERROR_COUNT below as well as the
   1098 	   message strings in strerror.c when adding new error codes here. */
   1099 
   1100 	/** Other error */
   1101 	LIBUSB_ERROR_OTHER = -99,
   1102 };
   1103 
   1104 /* Total number of error codes in enum libusb_error */
   1105 #define LIBUSB_ERROR_COUNT 14
   1106 
   1107 /** \ingroup asyncio
   1108  * Transfer status codes */
   1109 enum libusb_transfer_status {
   1110 	/** Transfer completed without error. Note that this does not indicate
   1111 	 * that the entire amount of requested data was transferred. */
   1112 	LIBUSB_TRANSFER_COMPLETED,
   1113 
   1114 	/** Transfer failed */
   1115 	LIBUSB_TRANSFER_ERROR,
   1116 
   1117 	/** Transfer timed out */
   1118 	LIBUSB_TRANSFER_TIMED_OUT,
   1119 
   1120 	/** Transfer was cancelled */
   1121 	LIBUSB_TRANSFER_CANCELLED,
   1122 
   1123 	/** For bulk/interrupt endpoints: halt condition detected (endpoint
   1124 	 * stalled). For control endpoints: control request not supported. */
   1125 	LIBUSB_TRANSFER_STALL,
   1126 
   1127 	/** Device was disconnected */
   1128 	LIBUSB_TRANSFER_NO_DEVICE,
   1129 
   1130 	/** Device sent more data than requested */
   1131 	LIBUSB_TRANSFER_OVERFLOW,
   1132 
   1133 	/* NB! Remember to update libusb_error_name()
   1134 	   when adding new status codes here. */
   1135 };
   1136 
   1137 /** \ingroup asyncio
   1138  * libusb_transfer.flags values */
   1139 enum libusb_transfer_flags {
   1140 	/** Report short frames as errors */
   1141 	LIBUSB_TRANSFER_SHORT_NOT_OK = 1<<0,
   1142 
   1143 	/** Automatically free() transfer buffer during libusb_free_transfer() */
   1144 	LIBUSB_TRANSFER_FREE_BUFFER = 1<<1,
   1145 
   1146 	/** Automatically call libusb_free_transfer() after callback returns.
   1147 	 * If this flag is set, it is illegal to call libusb_free_transfer()
   1148 	 * from your transfer callback, as this will result in a double-free
   1149 	 * when this flag is acted upon. */
   1150 	LIBUSB_TRANSFER_FREE_TRANSFER = 1<<2,
   1151 
   1152 	/** Terminate transfers that are a multiple of the endpoint's
   1153 	 * wMaxPacketSize with an extra zero length packet. This is useful
   1154 	 * when a device protocol mandates that each logical request is
   1155 	 * terminated by an incomplete packet (i.e. the logical requests are
   1156 	 * not separated by other means).
   1157 	 *
   1158 	 * This flag only affects host-to-device transfers to bulk and interrupt
   1159 	 * endpoints. In other situations, it is ignored.
   1160 	 *
   1161 	 * This flag only affects transfers with a length that is a multiple of
   1162 	 * the endpoint's wMaxPacketSize. On transfers of other lengths, this
   1163 	 * flag has no effect. Therefore, if you are working with a device that
   1164 	 * needs a ZLP whenever the end of the logical request falls on a packet
   1165 	 * boundary, then it is sensible to set this flag on <em>every</em>
   1166 	 * transfer (you do not have to worry about only setting it on transfers
   1167 	 * that end on the boundary).
   1168 	 *
   1169 	 * This flag is currently only supported on Linux.
   1170 	 * On other systems, libusb_submit_transfer() will return
   1171 	 * LIBUSB_ERROR_NOT_SUPPORTED for every transfer where this flag is set.
   1172 	 *
   1173 	 * Available since libusb-1.0.9.
   1174 	 */
   1175 	LIBUSB_TRANSFER_ADD_ZERO_PACKET = 1 << 3,
   1176 };
   1177 
   1178 /** \ingroup asyncio
   1179  * Isochronous packet descriptor. */
   1180 struct libusb_iso_packet_descriptor {
   1181 	/** Length of data to request in this packet */
   1182 	unsigned int length;
   1183 
   1184 	/** Amount of data that was actually transferred */
   1185 	unsigned int actual_length;
   1186 
   1187 	/** Status code for this packet */
   1188 	enum libusb_transfer_status status;
   1189 };
   1190 
   1191 struct libusb_transfer;
   1192 
   1193 /** \ingroup asyncio
   1194  * Asynchronous transfer callback function type. When submitting asynchronous
   1195  * transfers, you pass a pointer to a callback function of this type via the
   1196  * \ref libusb_transfer::callback "callback" member of the libusb_transfer
   1197  * structure. libusbx will call this function later, when the transfer has
   1198  * completed or failed. See \ref asyncio for more information.
   1199  * \param transfer The libusb_transfer struct the callback function is being
   1200  * notified about.
   1201  */
   1202 typedef void (LIBUSB_CALL *libusb_transfer_cb_fn)(struct libusb_transfer *transfer);
   1203 
   1204 /** \ingroup asyncio
   1205  * The generic USB transfer structure. The user populates this structure and
   1206  * then submits it in order to request a transfer. After the transfer has
   1207  * completed, the library populates the transfer with the results and passes
   1208  * it back to the user.
   1209  */
   1210 struct libusb_transfer {
   1211 	/** Handle of the device that this transfer will be submitted to */
   1212 	libusb_device_handle *dev_handle;
   1213 
   1214 	/** A bitwise OR combination of \ref libusb_transfer_flags. */
   1215 	uint8_t flags;
   1216 
   1217 	/** Address of the endpoint where this transfer will be sent. */
   1218 	unsigned char endpoint;
   1219 
   1220 	/** Type of the endpoint from \ref libusb_transfer_type */
   1221 	unsigned char type;
   1222 
   1223 	/** Timeout for this transfer in millseconds. A value of 0 indicates no
   1224 	 * timeout. */
   1225 	unsigned int timeout;
   1226 
   1227 	/** The status of the transfer. Read-only, and only for use within
   1228 	 * transfer callback function.
   1229 	 *
   1230 	 * If this is an isochronous transfer, this field may read COMPLETED even
   1231 	 * if there were errors in the frames. Use the
   1232 	 * \ref libusb_iso_packet_descriptor::status "status" field in each packet
   1233 	 * to determine if errors occurred. */
   1234 	enum libusb_transfer_status status;
   1235 
   1236 	/** Length of the data buffer */
   1237 	int length;
   1238 
   1239 	/** Actual length of data that was transferred. Read-only, and only for
   1240 	 * use within transfer callback function. Not valid for isochronous
   1241 	 * endpoint transfers. */
   1242 	int actual_length;
   1243 
   1244 	/** Callback function. This will be invoked when the transfer completes,
   1245 	 * fails, or is cancelled. */
   1246 	libusb_transfer_cb_fn callback;
   1247 
   1248 	/** User context data to pass to the callback function. */
   1249 	void *user_data;
   1250 
   1251 	/** Data buffer */
   1252 	unsigned char *buffer;
   1253 
   1254 	/** Number of isochronous packets. Only used for I/O with isochronous
   1255 	 * endpoints. */
   1256 	int num_iso_packets;
   1257 
   1258 	/** Isochronous packet descriptors, for isochronous transfers only. */
   1259 	struct libusb_iso_packet_descriptor iso_packet_desc
   1260 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
   1261 	[] /* valid C99 code */
   1262 #else
   1263 	[0] /* non-standard, but usually working code */
   1264 #endif
   1265 	;
   1266 };
   1267 
   1268 /** \ingroup misc
   1269  * Capabilities supported by an instance of libusb on the current running
   1270  * platform. Test if the loaded library supports a given capability by calling
   1271  * \ref libusb_has_capability().
   1272  */
   1273 enum libusb_capability {
   1274 	/** The libusb_has_capability() API is available. */
   1275 	LIBUSB_CAP_HAS_CAPABILITY = 0x0000,
   1276 	/** Hotplug support is available on this platform. */
   1277 	LIBUSB_CAP_HAS_HOTPLUG = 0x0001,
   1278 	/** The library can access HID devices without requiring user intervention.
   1279 	 * Note that before being able to actually access an HID device, you may
   1280 	 * still have to call additional libusbx functions such as
   1281 	 * \ref libusb_detach_kernel_driver(). */
   1282 	LIBUSB_CAP_HAS_HID_ACCESS = 0x0100,
   1283 	/** The library supports detaching of the default USB driver, using
   1284 	 * \ref libusb_detach_kernel_driver(), if one is set by the OS kernel */
   1285 	LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER = 0x0101
   1286 };
   1287 
   1288 /** \ingroup lib
   1289  *  Log message levels.
   1290  *  - LIBUSB_LOG_LEVEL_NONE (0)    : no messages ever printed by the library (default)
   1291  *  - LIBUSB_LOG_LEVEL_ERROR (1)   : error messages are printed to stderr
   1292  *  - LIBUSB_LOG_LEVEL_WARNING (2) : warning and error messages are printed to stderr
   1293  *  - LIBUSB_LOG_LEVEL_INFO (3)    : informational messages are printed to stdout, warning
   1294  *    and error messages are printed to stderr
   1295  *  - LIBUSB_LOG_LEVEL_DEBUG (4)   : debug and informational messages are printed to stdout,
   1296  *    warnings and errors to stderr
   1297  */
   1298 enum libusb_log_level {
   1299 	LIBUSB_LOG_LEVEL_NONE = 0,
   1300 	LIBUSB_LOG_LEVEL_ERROR,
   1301 	LIBUSB_LOG_LEVEL_WARNING,
   1302 	LIBUSB_LOG_LEVEL_INFO,
   1303 	LIBUSB_LOG_LEVEL_DEBUG,
   1304 };
   1305 
   1306 int LIBUSB_CALL libusb_init(libusb_context **ctx);
   1307 void LIBUSB_CALL libusb_exit(libusb_context *ctx);
   1308 void LIBUSB_CALL libusb_set_debug(libusb_context *ctx, int level);
   1309 const struct libusb_version * LIBUSB_CALL libusb_get_version(void);
   1310 int LIBUSB_CALL libusb_has_capability(uint32_t capability);
   1311 const char * LIBUSB_CALL libusb_error_name(int errcode);
   1312 int LIBUSB_CALL libusb_setlocale(const char *locale);
   1313 const char * LIBUSB_CALL libusb_strerror(enum libusb_error errcode);
   1314 
   1315 ssize_t LIBUSB_CALL libusb_get_device_list(libusb_context *ctx,
   1316 	libusb_device ***list);
   1317 void LIBUSB_CALL libusb_free_device_list(libusb_device **list,
   1318 	int unref_devices);
   1319 libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev);
   1320 void LIBUSB_CALL libusb_unref_device(libusb_device *dev);
   1321 
   1322 int LIBUSB_CALL libusb_get_configuration(libusb_device_handle *dev,
   1323 	int *config);
   1324 int LIBUSB_CALL libusb_get_device_descriptor(libusb_device *dev,
   1325 	struct libusb_device_descriptor *desc);
   1326 int LIBUSB_CALL libusb_get_active_config_descriptor(libusb_device *dev,
   1327 	struct libusb_config_descriptor **config);
   1328 int LIBUSB_CALL libusb_get_config_descriptor(libusb_device *dev,
   1329 	uint8_t config_index, struct libusb_config_descriptor **config);
   1330 int LIBUSB_CALL libusb_get_config_descriptor_by_value(libusb_device *dev,
   1331 	uint8_t bConfigurationValue, struct libusb_config_descriptor **config);
   1332 void LIBUSB_CALL libusb_free_config_descriptor(
   1333 	struct libusb_config_descriptor *config);
   1334 int LIBUSB_CALL libusb_get_ss_endpoint_companion_descriptor(
   1335 	struct libusb_context *ctx,
   1336 	const struct libusb_endpoint_descriptor *endpoint,
   1337 	struct libusb_ss_endpoint_companion_descriptor **ep_comp);
   1338 void LIBUSB_CALL libusb_free_ss_endpoint_companion_descriptor(
   1339 	struct libusb_ss_endpoint_companion_descriptor *ep_comp);
   1340 int LIBUSB_CALL libusb_get_bos_descriptor(libusb_device_handle *handle,
   1341 	struct libusb_bos_descriptor **bos);
   1342 void LIBUSB_CALL libusb_free_bos_descriptor(struct libusb_bos_descriptor *bos);
   1343 int LIBUSB_CALL libusb_get_usb_2_0_extension_descriptor(
   1344 	struct libusb_context *ctx,
   1345 	struct libusb_bos_dev_capability_descriptor *dev_cap,
   1346 	struct libusb_usb_2_0_extension_descriptor **usb_2_0_extension);
   1347 void LIBUSB_CALL libusb_free_usb_2_0_extension_descriptor(
   1348 	struct libusb_usb_2_0_extension_descriptor *usb_2_0_extension);
   1349 int LIBUSB_CALL libusb_get_ss_usb_device_capability_descriptor(
   1350 	struct libusb_context *ctx,
   1351 	struct libusb_bos_dev_capability_descriptor *dev_cap,
   1352 	struct libusb_ss_usb_device_capability_descriptor **ss_usb_device_cap);
   1353 void LIBUSB_CALL libusb_free_ss_usb_device_capability_descriptor(
   1354 	struct libusb_ss_usb_device_capability_descriptor *ss_usb_device_cap);
   1355 int LIBUSB_CALL libusb_get_container_id_descriptor(struct libusb_context *ctx,
   1356 	struct libusb_bos_dev_capability_descriptor *dev_cap,
   1357 	struct libusb_container_id_descriptor **container_id);
   1358 void LIBUSB_CALL libusb_free_container_id_descriptor(
   1359 	struct libusb_container_id_descriptor *container_id);
   1360 uint8_t LIBUSB_CALL libusb_get_bus_number(libusb_device *dev);
   1361 uint8_t LIBUSB_CALL libusb_get_port_number(libusb_device *dev);
   1362 int LIBUSB_CALL libusb_get_port_numbers(libusb_device *dev, uint8_t* port_numbers, int port_numbers_len);
   1363 LIBUSB_DEPRECATED_FOR(libusb_get_port_numbers)
   1364 int LIBUSB_CALL libusb_get_port_path(libusb_context *ctx, libusb_device *dev, uint8_t* path, uint8_t path_length);
   1365 libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev);
   1366 uint8_t LIBUSB_CALL libusb_get_device_address(libusb_device *dev);
   1367 int LIBUSB_CALL libusb_get_device_speed(libusb_device *dev);
   1368 int LIBUSB_CALL libusb_get_max_packet_size(libusb_device *dev,
   1369 	unsigned char endpoint);
   1370 int LIBUSB_CALL libusb_get_max_iso_packet_size(libusb_device *dev,
   1371 	unsigned char endpoint);
   1372 
   1373 int LIBUSB_CALL libusb_open(libusb_device *dev, libusb_device_handle **handle);
   1374 void LIBUSB_CALL libusb_close(libusb_device_handle *dev_handle);
   1375 libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle);
   1376 
   1377 int LIBUSB_CALL libusb_set_configuration(libusb_device_handle *dev,
   1378 	int configuration);
   1379 int LIBUSB_CALL libusb_claim_interface(libusb_device_handle *dev,
   1380 	int interface_number);
   1381 int LIBUSB_CALL libusb_release_interface(libusb_device_handle *dev,
   1382 	int interface_number);
   1383 
   1384 libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
   1385 	libusb_context *ctx, uint16_t vendor_id, uint16_t product_id);
   1386 
   1387 int LIBUSB_CALL libusb_set_interface_alt_setting(libusb_device_handle *dev,
   1388 	int interface_number, int alternate_setting);
   1389 int LIBUSB_CALL libusb_clear_halt(libusb_device_handle *dev,
   1390 	unsigned char endpoint);
   1391 int LIBUSB_CALL libusb_reset_device(libusb_device_handle *dev);
   1392 
   1393 int LIBUSB_CALL libusb_kernel_driver_active(libusb_device_handle *dev,
   1394 	int interface_number);
   1395 int LIBUSB_CALL libusb_detach_kernel_driver(libusb_device_handle *dev,
   1396 	int interface_number);
   1397 int LIBUSB_CALL libusb_attach_kernel_driver(libusb_device_handle *dev,
   1398 	int interface_number);
   1399 int LIBUSB_CALL libusb_set_auto_detach_kernel_driver(
   1400 	libusb_device_handle *dev, int enable);
   1401 
   1402 /* async I/O */
   1403 
   1404 /** \ingroup asyncio
   1405  * Get the data section of a control transfer. This convenience function is here
   1406  * to remind you that the data does not start until 8 bytes into the actual
   1407  * buffer, as the setup packet comes first.
   1408  *
   1409  * Calling this function only makes sense from a transfer callback function,
   1410  * or situations where you have already allocated a suitably sized buffer at
   1411  * transfer->buffer.
   1412  *
   1413  * \param transfer a transfer
   1414  * \returns pointer to the first byte of the data section
   1415  */
   1416 static inline unsigned char *libusb_control_transfer_get_data(
   1417 	struct libusb_transfer *transfer)
   1418 {
   1419 	return transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE;
   1420 }
   1421 
   1422 /** \ingroup asyncio
   1423  * Get the control setup packet of a control transfer. This convenience
   1424  * function is here to remind you that the control setup occupies the first
   1425  * 8 bytes of the transfer data buffer.
   1426  *
   1427  * Calling this function only makes sense from a transfer callback function,
   1428  * or situations where you have already allocated a suitably sized buffer at
   1429  * transfer->buffer.
   1430  *
   1431  * \param transfer a transfer
   1432  * \returns a casted pointer to the start of the transfer data buffer
   1433  */
   1434 static inline struct libusb_control_setup *libusb_control_transfer_get_setup(
   1435 	struct libusb_transfer *transfer)
   1436 {
   1437 	return (struct libusb_control_setup *) transfer->buffer;
   1438 }
   1439 
   1440 /** \ingroup asyncio
   1441  * Helper function to populate the setup packet (first 8 bytes of the data
   1442  * buffer) for a control transfer. The wIndex, wValue and wLength values should
   1443  * be given in host-endian byte order.
   1444  *
   1445  * \param buffer buffer to output the setup packet into
   1446  * \param bmRequestType see the
   1447  * \ref libusb_control_setup::bmRequestType "bmRequestType" field of
   1448  * \ref libusb_control_setup
   1449  * \param bRequest see the
   1450  * \ref libusb_control_setup::bRequest "bRequest" field of
   1451  * \ref libusb_control_setup
   1452  * \param wValue see the
   1453  * \ref libusb_control_setup::wValue "wValue" field of
   1454  * \ref libusb_control_setup
   1455  * \param wIndex see the
   1456  * \ref libusb_control_setup::wIndex "wIndex" field of
   1457  * \ref libusb_control_setup
   1458  * \param wLength see the
   1459  * \ref libusb_control_setup::wLength "wLength" field of
   1460  * \ref libusb_control_setup
   1461  */
   1462 static inline void libusb_fill_control_setup(unsigned char *buffer,
   1463 	uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
   1464 	uint16_t wLength)
   1465 {
   1466 	struct libusb_control_setup *setup = (struct libusb_control_setup *) buffer;
   1467 	setup->bmRequestType = bmRequestType;
   1468 	setup->bRequest = bRequest;
   1469 	setup->wValue = libusb_cpu_to_le16(wValue);
   1470 	setup->wIndex = libusb_cpu_to_le16(wIndex);
   1471 	setup->wLength = libusb_cpu_to_le16(wLength);
   1472 }
   1473 
   1474 struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(int iso_packets);
   1475 int LIBUSB_CALL libusb_submit_transfer(struct libusb_transfer *transfer);
   1476 int LIBUSB_CALL libusb_cancel_transfer(struct libusb_transfer *transfer);
   1477 void LIBUSB_CALL libusb_free_transfer(struct libusb_transfer *transfer);
   1478 
   1479 /** \ingroup asyncio
   1480  * Helper function to populate the required \ref libusb_transfer fields
   1481  * for a control transfer.
   1482  *
   1483  * If you pass a transfer buffer to this function, the first 8 bytes will
   1484  * be interpreted as a control setup packet, and the wLength field will be
   1485  * used to automatically populate the \ref libusb_transfer::length "length"
   1486  * field of the transfer. Therefore the recommended approach is:
   1487  * -# Allocate a suitably sized data buffer (including space for control setup)
   1488  * -# Call libusb_fill_control_setup()
   1489  * -# If this is a host-to-device transfer with a data stage, put the data
   1490  *    in place after the setup packet
   1491  * -# Call this function
   1492  * -# Call libusb_submit_transfer()
   1493  *
   1494  * It is also legal to pass a NULL buffer to this function, in which case this
   1495  * function will not attempt to populate the length field. Remember that you
   1496  * must then populate the buffer and length fields later.
   1497  *
   1498  * \param transfer the transfer to populate
   1499  * \param dev_handle handle of the device that will handle the transfer
   1500  * \param buffer data buffer. If provided, this function will interpret the
   1501  * first 8 bytes as a setup packet and infer the transfer length from that.
   1502  * \param callback callback function to be invoked on transfer completion
   1503  * \param user_data user data to pass to callback function
   1504  * \param timeout timeout for the transfer in milliseconds
   1505  */
   1506 static inline void libusb_fill_control_transfer(
   1507 	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
   1508 	unsigned char *buffer, libusb_transfer_cb_fn callback, void *user_data,
   1509 	unsigned int timeout)
   1510 {
   1511 	struct libusb_control_setup *setup = (struct libusb_control_setup *) buffer;
   1512 	transfer->dev_handle = dev_handle;
   1513 	transfer->endpoint = 0;
   1514 	transfer->type = LIBUSB_TRANSFER_TYPE_CONTROL;
   1515 	transfer->timeout = timeout;
   1516 	transfer->buffer = buffer;
   1517 	if (setup)
   1518 		transfer->length = (int) (LIBUSB_CONTROL_SETUP_SIZE
   1519 			+ libusb_le16_to_cpu(setup->wLength));
   1520 	transfer->user_data = user_data;
   1521 	transfer->callback = callback;
   1522 }
   1523 
   1524 /** \ingroup asyncio
   1525  * Helper function to populate the required \ref libusb_transfer fields
   1526  * for a bulk transfer.
   1527  *
   1528  * \param transfer the transfer to populate
   1529  * \param dev_handle handle of the device that will handle the transfer
   1530  * \param endpoint address of the endpoint where this transfer will be sent
   1531  * \param buffer data buffer
   1532  * \param length length of data buffer
   1533  * \param callback callback function to be invoked on transfer completion
   1534  * \param user_data user data to pass to callback function
   1535  * \param timeout timeout for the transfer in milliseconds
   1536  */
   1537 static inline void libusb_fill_bulk_transfer(struct libusb_transfer *transfer,
   1538 	libusb_device_handle *dev_handle, unsigned char endpoint,
   1539 	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
   1540 	void *user_data, unsigned int timeout)
   1541 {
   1542 	transfer->dev_handle = dev_handle;
   1543 	transfer->endpoint = endpoint;
   1544 	transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
   1545 	transfer->timeout = timeout;
   1546 	transfer->buffer = buffer;
   1547 	transfer->length = length;
   1548 	transfer->user_data = user_data;
   1549 	transfer->callback = callback;
   1550 }
   1551 
   1552 /** \ingroup asyncio
   1553  * Helper function to populate the required \ref libusb_transfer fields
   1554  * for an interrupt transfer.
   1555  *
   1556  * \param transfer the transfer to populate
   1557  * \param dev_handle handle of the device that will handle the transfer
   1558  * \param endpoint address of the endpoint where this transfer will be sent
   1559  * \param buffer data buffer
   1560  * \param length length of data buffer
   1561  * \param callback callback function to be invoked on transfer completion
   1562  * \param user_data user data to pass to callback function
   1563  * \param timeout timeout for the transfer in milliseconds
   1564  */
   1565 static inline void libusb_fill_interrupt_transfer(
   1566 	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
   1567 	unsigned char endpoint, unsigned char *buffer, int length,
   1568 	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
   1569 {
   1570 	transfer->dev_handle = dev_handle;
   1571 	transfer->endpoint = endpoint;
   1572 	transfer->type = LIBUSB_TRANSFER_TYPE_INTERRUPT;
   1573 	transfer->timeout = timeout;
   1574 	transfer->buffer = buffer;
   1575 	transfer->length = length;
   1576 	transfer->user_data = user_data;
   1577 	transfer->callback = callback;
   1578 }
   1579 
   1580 /** \ingroup asyncio
   1581  * Helper function to populate the required \ref libusb_transfer fields
   1582  * for an isochronous transfer.
   1583  *
   1584  * \param transfer the transfer to populate
   1585  * \param dev_handle handle of the device that will handle the transfer
   1586  * \param endpoint address of the endpoint where this transfer will be sent
   1587  * \param buffer data buffer
   1588  * \param length length of data buffer
   1589  * \param num_iso_packets the number of isochronous packets
   1590  * \param callback callback function to be invoked on transfer completion
   1591  * \param user_data user data to pass to callback function
   1592  * \param timeout timeout for the transfer in milliseconds
   1593  */
   1594 static inline void libusb_fill_iso_transfer(struct libusb_transfer *transfer,
   1595 	libusb_device_handle *dev_handle, unsigned char endpoint,
   1596 	unsigned char *buffer, int length, int num_iso_packets,
   1597 	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
   1598 {
   1599 	transfer->dev_handle = dev_handle;
   1600 	transfer->endpoint = endpoint;
   1601 	transfer->type = LIBUSB_TRANSFER_TYPE_ISOCHRONOUS;
   1602 	transfer->timeout = timeout;
   1603 	transfer->buffer = buffer;
   1604 	transfer->length = length;
   1605 	transfer->num_iso_packets = num_iso_packets;
   1606 	transfer->user_data = user_data;
   1607 	transfer->callback = callback;
   1608 }
   1609 
   1610 /** \ingroup asyncio
   1611  * Convenience function to set the length of all packets in an isochronous
   1612  * transfer, based on the num_iso_packets field in the transfer structure.
   1613  *
   1614  * \param transfer a transfer
   1615  * \param length the length to set in each isochronous packet descriptor
   1616  * \see libusb_get_max_packet_size()
   1617  */
   1618 static inline void libusb_set_iso_packet_lengths(
   1619 	struct libusb_transfer *transfer, unsigned int length)
   1620 {
   1621 	int i;
   1622 	for (i = 0; i < transfer->num_iso_packets; i++)
   1623 		transfer->iso_packet_desc[i].length = length;
   1624 }
   1625 
   1626 /** \ingroup asyncio
   1627  * Convenience function to locate the position of an isochronous packet
   1628  * within the buffer of an isochronous transfer.
   1629  *
   1630  * This is a thorough function which loops through all preceding packets,
   1631  * accumulating their lengths to find the position of the specified packet.
   1632  * Typically you will assign equal lengths to each packet in the transfer,
   1633  * and hence the above method is sub-optimal. You may wish to use
   1634  * libusb_get_iso_packet_buffer_simple() instead.
   1635  *
   1636  * \param transfer a transfer
   1637  * \param packet the packet to return the address of
   1638  * \returns the base address of the packet buffer inside the transfer buffer,
   1639  * or NULL if the packet does not exist.
   1640  * \see libusb_get_iso_packet_buffer_simple()
   1641  */
   1642 static inline unsigned char *libusb_get_iso_packet_buffer(
   1643 	struct libusb_transfer *transfer, unsigned int packet)
   1644 {
   1645 	int i;
   1646 	size_t offset = 0;
   1647 	int _packet;
   1648 
   1649 	/* oops..slight bug in the API. packet is an unsigned int, but we use
   1650 	 * signed integers almost everywhere else. range-check and convert to
   1651 	 * signed to avoid compiler warnings. FIXME for libusb-2. */
   1652 	if (packet > INT_MAX)
   1653 		return NULL;
   1654 	_packet = (int) packet;
   1655 
   1656 	if (_packet >= transfer->num_iso_packets)
   1657 		return NULL;
   1658 
   1659 	for (i = 0; i < _packet; i++)
   1660 		offset += transfer->iso_packet_desc[i].length;
   1661 
   1662 	return transfer->buffer + offset;
   1663 }
   1664 
   1665 /** \ingroup asyncio
   1666  * Convenience function to locate the position of an isochronous packet
   1667  * within the buffer of an isochronous transfer, for transfers where each
   1668  * packet is of identical size.
   1669  *
   1670  * This function relies on the assumption that every packet within the transfer
   1671  * is of identical size to the first packet. Calculating the location of
   1672  * the packet buffer is then just a simple calculation:
   1673  * <tt>buffer + (packet_size * packet)</tt>
   1674  *
   1675  * Do not use this function on transfers other than those that have identical
   1676  * packet lengths for each packet.
   1677  *
   1678  * \param transfer a transfer
   1679  * \param packet the packet to return the address of
   1680  * \returns the base address of the packet buffer inside the transfer buffer,
   1681  * or NULL if the packet does not exist.
   1682  * \see libusb_get_iso_packet_buffer()
   1683  */
   1684 static inline unsigned char *libusb_get_iso_packet_buffer_simple(
   1685 	struct libusb_transfer *transfer, unsigned int packet)
   1686 {
   1687 	int _packet;
   1688 
   1689 	/* oops..slight bug in the API. packet is an unsigned int, but we use
   1690 	 * signed integers almost everywhere else. range-check and convert to
   1691 	 * signed to avoid compiler warnings. FIXME for libusb-2. */
   1692 	if (packet > INT_MAX)
   1693 		return NULL;
   1694 	_packet = (int) packet;
   1695 
   1696 	if (_packet >= transfer->num_iso_packets)
   1697 		return NULL;
   1698 
   1699 	return transfer->buffer + ((int) transfer->iso_packet_desc[0].length * _packet);
   1700 }
   1701 
   1702 /* sync I/O */
   1703 
   1704 int LIBUSB_CALL libusb_control_transfer(libusb_device_handle *dev_handle,
   1705 	uint8_t request_type, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
   1706 	unsigned char *data, uint16_t wLength, unsigned int timeout);
   1707 
   1708 int LIBUSB_CALL libusb_bulk_transfer(libusb_device_handle *dev_handle,
   1709 	unsigned char endpoint, unsigned char *data, int length,
   1710 	int *actual_length, unsigned int timeout);
   1711 
   1712 int LIBUSB_CALL libusb_interrupt_transfer(libusb_device_handle *dev_handle,
   1713 	unsigned char endpoint, unsigned char *data, int length,
   1714 	int *actual_length, unsigned int timeout);
   1715 
   1716 /** \ingroup desc
   1717  * Retrieve a descriptor from the default control pipe.
   1718  * This is a convenience function which formulates the appropriate control
   1719  * message to retrieve the descriptor.
   1720  *
   1721  * \param dev a device handle
   1722  * \param desc_type the descriptor type, see \ref libusb_descriptor_type
   1723  * \param desc_index the index of the descriptor to retrieve
   1724  * \param data output buffer for descriptor
   1725  * \param length size of data buffer
   1726  * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
   1727  */
   1728 static inline int libusb_get_descriptor(libusb_device_handle *dev,
   1729 	uint8_t desc_type, uint8_t desc_index, unsigned char *data, int length)
   1730 {
   1731 	return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
   1732 		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t) ((desc_type << 8) | desc_index),
   1733 		0, data, (uint16_t) length, 1000);
   1734 }
   1735 
   1736 /** \ingroup desc
   1737  * Retrieve a descriptor from a device.
   1738  * This is a convenience function which formulates the appropriate control
   1739  * message to retrieve the descriptor. The string returned is Unicode, as
   1740  * detailed in the USB specifications.
   1741  *
   1742  * \param dev a device handle
   1743  * \param desc_index the index of the descriptor to retrieve
   1744  * \param langid the language ID for the string descriptor
   1745  * \param data output buffer for descriptor
   1746  * \param length size of data buffer
   1747  * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
   1748  * \see libusb_get_string_descriptor_ascii()
   1749  */
   1750 static inline int libusb_get_string_descriptor(libusb_device_handle *dev,
   1751 	uint8_t desc_index, uint16_t langid, unsigned char *data, int length)
   1752 {
   1753 	return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
   1754 		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t)((LIBUSB_DT_STRING << 8) | desc_index),
   1755 		langid, data, (uint16_t) length, 1000);
   1756 }
   1757 
   1758 int LIBUSB_CALL libusb_get_string_descriptor_ascii(libusb_device_handle *dev,
   1759 	uint8_t desc_index, unsigned char *data, int length);
   1760 
   1761 /* polling and timeouts */
   1762 
   1763 int LIBUSB_CALL libusb_try_lock_events(libusb_context *ctx);
   1764 void LIBUSB_CALL libusb_lock_events(libusb_context *ctx);
   1765 void LIBUSB_CALL libusb_unlock_events(libusb_context *ctx);
   1766 int LIBUSB_CALL libusb_event_handling_ok(libusb_context *ctx);
   1767 int LIBUSB_CALL libusb_event_handler_active(libusb_context *ctx);
   1768 void LIBUSB_CALL libusb_lock_event_waiters(libusb_context *ctx);
   1769 void LIBUSB_CALL libusb_unlock_event_waiters(libusb_context *ctx);
   1770 int LIBUSB_CALL libusb_wait_for_event(libusb_context *ctx, struct timeval *tv);
   1771 
   1772 int LIBUSB_CALL libusb_handle_events_timeout(libusb_context *ctx,
   1773 	struct timeval *tv);
   1774 int LIBUSB_CALL libusb_handle_events_timeout_completed(libusb_context *ctx,
   1775 	struct timeval *tv, int *completed);
   1776 int LIBUSB_CALL libusb_handle_events(libusb_context *ctx);
   1777 int LIBUSB_CALL libusb_handle_events_completed(libusb_context *ctx, int *completed);
   1778 int LIBUSB_CALL libusb_handle_events_locked(libusb_context *ctx,
   1779 	struct timeval *tv);
   1780 int LIBUSB_CALL libusb_pollfds_handle_timeouts(libusb_context *ctx);
   1781 int LIBUSB_CALL libusb_get_next_timeout(libusb_context *ctx,
   1782 	struct timeval *tv);
   1783 
   1784 /** \ingroup poll
   1785  * File descriptor for polling
   1786  */
   1787 struct libusb_pollfd {
   1788 	/** Numeric file descriptor */
   1789 	int fd;
   1790 
   1791 	/** Event flags to poll for from <poll.h>. POLLIN indicates that you
   1792 	 * should monitor this file descriptor for becoming ready to read from,
   1793 	 * and POLLOUT indicates that you should monitor this file descriptor for
   1794 	 * nonblocking write readiness. */
   1795 	short events;
   1796 };
   1797 
   1798 /** \ingroup poll
   1799  * Callback function, invoked when a new file descriptor should be added
   1800  * to the set of file descriptors monitored for events.
   1801  * \param fd the new file descriptor
   1802  * \param events events to monitor for, see \ref libusb_pollfd for a
   1803  * description
   1804  * \param user_data User data pointer specified in
   1805  * libusb_set_pollfd_notifiers() call
   1806  * \see libusb_set_pollfd_notifiers()
   1807  */
   1808 typedef void (LIBUSB_CALL *libusb_pollfd_added_cb)(int fd, short events,
   1809 	void *user_data);
   1810 
   1811 /** \ingroup poll
   1812  * Callback function, invoked when a file descriptor should be removed from
   1813  * the set of file descriptors being monitored for events. After returning
   1814  * from this callback, do not use that file descriptor again.
   1815  * \param fd the file descriptor to stop monitoring
   1816  * \param user_data User data pointer specified in
   1817  * libusb_set_pollfd_notifiers() call
   1818  * \see libusb_set_pollfd_notifiers()
   1819  */
   1820 typedef void (LIBUSB_CALL *libusb_pollfd_removed_cb)(int fd, void *user_data);
   1821 
   1822 const struct libusb_pollfd ** LIBUSB_CALL libusb_get_pollfds(
   1823 	libusb_context *ctx);
   1824 void LIBUSB_CALL libusb_set_pollfd_notifiers(libusb_context *ctx,
   1825 	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
   1826 	void *user_data);
   1827 
   1828 /** \ingroup hotplug
   1829  * Callback handle.
   1830  *
   1831  * Callbacks handles are generated by libusb_hotplug_register_callback()
   1832  * and can be used to deregister callbacks. Callback handles are unique
   1833  * per libusb_context and it is safe to call libusb_hotplug_deregister_callback()
   1834  * on an already deregisted callback.
   1835  *
   1836  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1837  *
   1838  * For more information, see \ref hotplug.
   1839  */
   1840 typedef int libusb_hotplug_callback_handle;
   1841 
   1842 /** \ingroup hotplug
   1843  *
   1844  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1845  *
   1846  * Flags for hotplug events */
   1847 typedef enum {
   1848 	/** Arm the callback and fire it for all matching currently attached devices. */
   1849 	LIBUSB_HOTPLUG_ENUMERATE = 1,
   1850 } libusb_hotplug_flag;
   1851 
   1852 /** \ingroup hotplug
   1853  *
   1854  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1855  *
   1856  * Hotplug events */
   1857 typedef enum {
   1858 	/** A device has been plugged in and is ready to use */
   1859 	LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED = 0x01,
   1860 
   1861 	/** A device has left and is no longer available.
   1862 	 * It is the user's responsibility to call libusb_close on any handle associated with a disconnected device.
   1863 	 * It is safe to call libusb_get_device_descriptor on a device that has left */
   1864 	LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT    = 0x02,
   1865 } libusb_hotplug_event;
   1866 
   1867 /** \ingroup hotplug
   1868  * Wildcard matching for hotplug events */
   1869 #define LIBUSB_HOTPLUG_MATCH_ANY -1
   1870 
   1871 /** \ingroup hotplug
   1872  * Hotplug callback function type. When requesting hotplug event notifications,
   1873  * you pass a pointer to a callback function of this type.
   1874  *
   1875  * This callback may be called by an internal event thread and as such it is
   1876  * recommended the callback do minimal processing before returning.
   1877  *
   1878  * libusbx will call this function later, when a matching event had happened on
   1879  * a matching device. See \ref hotplug for more information.
   1880  *
   1881  * It is safe to call either libusb_hotplug_register_callback() or
   1882  * libusb_hotplug_deregister_callback() from within a callback function.
   1883  *
   1884  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1885  *
   1886  * \param libusb_context context of this notification
   1887  * \param device         libusb_device this event occurred on
   1888  * \param event          event that occurred
   1889  * \param user_data      user data provided when this callback was registered
   1890  * \returns bool whether this callback is finished processing events.
   1891  *                       returning 1 will cause this callback to be deregistered
   1892  */
   1893 typedef int (LIBUSB_CALL *libusb_hotplug_callback_fn)(libusb_context *ctx,
   1894 						libusb_device *device,
   1895 						libusb_hotplug_event event,
   1896 						void *user_data);
   1897 
   1898 /** \ingroup hotplug
   1899  * Register a hotplug callback function
   1900  *
   1901  * Register a callback with the libusb_context. The callback will fire
   1902  * when a matching event occurs on a matching device. The callback is
   1903  * armed until either it is deregistered with libusb_hotplug_deregister_callback()
   1904  * or the supplied callback returns 1 to indicate it is finished processing events.
   1905  *
   1906  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1907  *
   1908  * \param[in] ctx context to register this callback with
   1909  * \param[in] events bitwise or of events that will trigger this callback. See \ref
   1910  *            libusb_hotplug_event
   1911  * \param[in] flags hotplug callback flags. See \ref libusb_hotplug_flag
   1912  * \param[in] vendor_id the vendor id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
   1913  * \param[in] product_id the product id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
   1914  * \param[in] dev_class the device class to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
   1915  * \param[in] cb_fn the function to be invoked on a matching event/device
   1916  * \param[in] user_data user data to pass to the callback function
   1917  * \param[out] handle pointer to store the handle of the allocated callback (can be NULL)
   1918  * \returns LIBUSB_SUCCESS on success LIBUSB_ERROR code on failure
   1919  */
   1920 int LIBUSB_CALL libusb_hotplug_register_callback(libusb_context *ctx,
   1921 						libusb_hotplug_event events,
   1922 						libusb_hotplug_flag flags,
   1923 						int vendor_id, int product_id,
   1924 						int dev_class,
   1925 						libusb_hotplug_callback_fn cb_fn,
   1926 						void *user_data,
   1927 						libusb_hotplug_callback_handle *handle);
   1928 
   1929 /** \ingroup hotplug
   1930  * Deregisters a hotplug callback.
   1931  *
   1932  * Deregister a callback from a libusb_context. This function is safe to call from within
   1933  * a hotplug callback.
   1934  *
   1935  * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102
   1936  *
   1937  * \param[in] ctx context this callback is registered with
   1938  * \param[in] handle the handle of the callback to deregister
   1939  */
   1940 void LIBUSB_CALL libusb_hotplug_deregister_callback(libusb_context *ctx,
   1941 						libusb_hotplug_callback_handle handle);
   1942 
   1943 #ifdef __cplusplus
   1944 }
   1945 #endif
   1946 
   1947 #ifdef _MSC_VER
   1948 #pragma warning(pop)
   1949 #endif
   1950 
   1951 #endif
   1952