2 .\" Copyright (c) 2008 Hans Petter Selasky
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
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35 .Nd "USB access library"
41 USB access library (libusb -lusb)
48 .Fn libusb20_tr_close "struct libusb20_transfer *xfer"
50 .Fn libusb20_tr_open "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no"
51 .Fn libusb20_tr_open_stream "struct libusb20_transfer *xfer" "uint32_t max_buf_size" "uint32_t max_frame_count" "uint8_t ep_no" "uint16_t stream_id"
52 .Ft struct libusb20_transfer*
53 .Fn libusb20_tr_get_pointer "struct libusb20_device *pdev" "uint16_t tr_index"
55 .Fn libusb20_tr_get_time_complete "struct libusb20_transfer *xfer"
57 .Fn libusb20_tr_get_actual_frames "struct libusb20_transfer *xfer"
59 .Fn libusb20_tr_get_actual_length "struct libusb20_transfer *xfer"
61 .Fn libusb20_tr_get_max_frames "struct libusb20_transfer *xfer"
63 .Fn libusb20_tr_get_max_packet_length "struct libusb20_transfer *xfer"
65 .Fn libusb20_tr_get_max_total_length "struct libusb20_transfer *xfer"
67 .Fn libusb20_tr_get_status "struct libusb20_transfer *xfer"
69 .Fn libusb20_tr_pending "struct libusb20_transfer *xfer"
71 .Fn libusb20_tr_callback_wrapper "struct libusb20_transfer *xfer"
73 .Fn libusb20_tr_clear_stall_sync "struct libusb20_transfer *xfer"
75 .Fn libusb20_tr_drain "struct libusb20_transfer *xfer"
77 .Fn libusb20_tr_set_buffer "struct libusb20_transfer *xfer" "void *buffer" "uint16_t fr_index"
79 .Fn libusb20_tr_set_callback "struct libusb20_transfer *xfer" "libusb20_tr_callback_t *cb"
81 .Fn libusb20_tr_set_flags "struct libusb20_transfer *xfer" "uint8_t flags"
83 .Fn libusb20_tr_get_length "struct libusb20_transfer *xfer" "uint16_t fr_index"
85 .Fn libusb20_tr_set_length "struct libusb20_transfer *xfer" "uint32_t length" "uint16_t fr_index"
87 .Fn libusb20_tr_set_priv_sc0 "struct libusb20_transfer *xfer" "void *sc0"
89 .Fn libusb20_tr_set_priv_sc1 "struct libusb20_transfer *xfer" "void *sc1"
91 .Fn libusb20_tr_set_timeout "struct libusb20_transfer *xfer" "uint32_t timeout"
93 .Fn libusb20_tr_set_total_frames "struct libusb20_transfer *xfer" "uint32_t nframes"
95 .Fn libusb20_tr_setup_bulk "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
97 .Fn libusb20_tr_setup_control "struct libusb20_transfer *xfer" "void *psetup" "void *pbuf" "uint32_t timeout"
99 .Fn libusb20_tr_setup_intr "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t timeout"
101 .Fn libusb20_tr_setup_isoc "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint61_t fr_index"
103 .Fn libusb20_tr_bulk_intr_sync "struct libusb20_transfer *xfer" "void *pbuf" "uint32_t length" "uint32_t *pactlen" "uint32_t timeout"
105 .Fn libusb20_tr_start "struct libusb20_transfer *xfer"
107 .Fn libusb20_tr_stop "struct libusb20_transfer *xfer"
109 .Fn libusb20_tr_submit "struct libusb20_transfer *xfer"
111 .Fn libusb20_tr_get_priv_sc0 "struct libusb20_transfer *xfer"
113 .Fn libusb20_tr_get_priv_sc1 "struct libusb20_transfer *xfer"
115 .Fn libusb20_dev_get_backend_name "struct libusb20_device *"
117 .Fn libusb20_dev_get_port_path "struct libusb20_device *pdev" "uint8_t *buf" "uint8_t bufsize"
119 .Fn libusb20_dev_get_info "struct libusb20_device *pdev" "struct usb_device_info *pinfo"
121 .Fn libusb20_dev_get_iface_desc "struct libusb20_device *pdev" "uint8_t iface_index" "char *buf" "uint8_t len"
123 .Fn libusb20_dev_get_desc "struct libusb20_device *pdev"
125 .Fn libusb20_dev_close "struct libusb20_device *pdev"
127 .Fn libusb20_dev_detach_kernel_driver "struct libusb20_device *pdev" "uint8_t iface_index"
129 .Fn libusb20_dev_set_config_index "struct libusb20_device *pdev" "uint8_t configIndex"
131 .Fn libusb20_dev_get_debug "struct libusb20_device *pdev"
133 .Fn libusb20_dev_get_fd "struct libusb20_device *pdev"
135 .Fn libusb20_dev_kernel_driver_active "struct libusb20_device *pdev" "uint8_t iface_index"
137 .Fn libusb20_dev_open "struct libusb20_device *pdev" "uint16_t transfer_max"
139 .Fn libusb20_dev_process "struct libusb20_device *pdev"
141 .Fn libusb20_dev_request_sync "struct libusb20_device *pdev" "struct LIBUSB20_CONTROL_SETUP_DECODED *setup" "void *data" "uint16_t *pactlen" "uint32_t timeout" "uint8_t flags"
143 .Fn libusb20_dev_req_string_sync "struct libusb20_device *pdev" "uint8_t index" "uint16_t langid" "void *ptr" "uint16_t len"
145 .Fn libusb20_dev_req_string_simple_sync "struct libusb20_device *pdev" "uint8_t index" "void *ptr" "uint16_t len"
147 .Fn libusb20_dev_reset "struct libusb20_device *pdev"
149 .Fn libusb20_dev_check_connected "struct libusb20_device *pdev"
151 .Fn libusb20_dev_set_power_mode "struct libusb20_device *pdev" "uint8_t power_mode"
153 .Fn libusb20_dev_get_power_mode "struct libusb20_device *pdev"
155 .Fn libusb20_dev_get_power_usage "struct libusb20_device *pdev"
157 .Fn libusb20_dev_set_alt_index "struct libusb20_device *pdev" "uint8_t iface_index" "uint8_t alt_index"
158 .Ft struct LIBUSB20_DEVICE_DESC_DECODED *
159 .Fn libusb20_dev_get_device_desc "struct libusb20_device *pdev"
160 .Ft struct libusb20_config *
161 .Fn libusb20_dev_alloc_config "struct libusb20_device *pdev" "uint8_t config_index"
162 .Ft struct libusb20_device *
163 .Fn libusb20_dev_alloc "void"
165 .Fn libusb20_dev_get_address "struct libusb20_device *pdev"
167 .Fn libusb20_dev_get_parent_address "struct libusb20_device *pdev"
169 .Fn libusb20_dev_get_parent_port "struct libusb20_device *pdev"
171 .Fn libusb20_dev_get_bus_number "struct libusb20_device *pdev"
173 .Fn libusb20_dev_get_mode "struct libusb20_device *pdev"
175 .Fn libusb20_dev_get_speed "struct libusb20_device *pdev"
177 .Fn libusb20_dev_get_config_index "struct libusb20_device *pdev"
179 .Fn libusb20_dev_free "struct libusb20_device *pdev"
181 .Fn libusb20_dev_set_debug "struct libusb20_device *pdev" "int debug"
183 .Fn libusb20_dev_wait_process "struct libusb20_device *pdev" "int timeout"
185 .Fn libusb20_be_get_template "struct libusb20_backend *pbe" "int *ptemp"
187 .Fn libusb20_be_set_template "struct libusb20_backend *pbe" "int temp"
189 .Fn libusb20_be_get_dev_quirk "struct libusb20_backend *pber" "uint16_t index" "struct libusb20_quirk *pq"
191 .Fn libusb20_be_get_quirk_name "struct libusb20_backend *pbe" "uint16_t index" "struct libusb20_quirk *pq"
193 .Fn libusb20_be_add_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
195 .Fn libusb20_be_remove_dev_quirk "struct libusb20_backend *pbe" "struct libusb20_quirk *pq"
196 .Ft struct libusb20_backend *
197 .Fn libusb20_be_alloc_default "void"
198 .Ft struct libusb20_backend *
199 .Fn libusb20_be_alloc_freebsd "void"
200 .Ft struct libusb20_backend *
201 .Fn libusb20_be_alloc_linux "void"
202 .Ft struct libusb20_device *
203 .Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
205 .Fn libusb20_be_dequeue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
207 .Fn libusb20_be_enqueue_device "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
209 .Fn libusb20_be_free "struct libusb20_backend *pbe"
211 .Fn libusb20_me_get_1 "const struct libusb20_me_struct *me" "uint16_t off"
213 .Fn libusb20_me_get_2 "const struct libusb20_me_struct *me" "uint16_t off"
215 .Fn libusb20_me_encode "void *pdata" "uint16_t len" "const void *pdecoded"
217 .Fn libusb20_me_decode "const void *pdata" "uint16_t len" "void *pdecoded"
218 .Ft "const uint8_t *"
219 .Fn libusb20_desc_foreach "const struct libusb20_me_struct *me" "const uint8_t *pdesc"
221 .Fn libusb20_strerror "int code"
223 .Fn libusb20_error_name "int code"
230 library implements functions to be able to easily access and control
231 USB through the USB file system interface.
234 interfaces are specific to the
236 usb stack and are not available on other operating systems, portable
237 applications should consider using
241 .Sh USB TRANSFER OPERATIONS
244 .Fn libusb20_tr_close
245 will release all kernel resources associated with an USB
248 This function returns zero upon success.
250 Non-zero return values indicate a LIBUSB20_ERROR value.
255 will allocate kernel buffer resources according to
259 associated with an USB
261 and bind the transfer to the specified
264 is the minimum buffer size which the data transport layer has to support.
269 library will use wMaxPacketSize to compute the buffer size.
270 This can be useful for isochronous transfers.
271 The actual buffer size can be greater than
274 .Fn libusb20_tr_get_max_total_length .
278 is OR'ed with LIBUSB20_MAX_FRAME_PRE_SCALE the remaining part of the
279 argument is converted from milliseconds into the actual number of
280 frames rounded up, when this function returns.
281 This flag is only valid for ISOCHRONOUS transfers and has no effect
282 for other transfer types.
283 The actual number of frames setup is found by calling
284 .Fn libusb20_tr_get_max_frames .
286 This function returns zero upon success.
288 Non-zero return values indicate a LIBUSB20_ERROR value.
292 .Fn libusb20_tr_open_stream
295 except that a stream ID can be specified for BULK endpoints having
298 can be used to open stream ID zero.
302 .Fn libusb20_tr_get_pointer
303 will return a pointer to the allocated USB transfer according to the
309 This function returns NULL in case of failure.
313 .Fn libusb20_tr_get_time_complete
314 will return the completion time of an USB transfer in
315 millisecond units. This function is most useful for isochronous USB
316 transfers when doing echo cancelling.
320 .Fn libusb20_tr_get_actual_frames
321 will return the actual number of USB frames after an USB
322 transfer completed. A value of zero means that no data was transferred.
326 .Fn libusb20_tr_get_actual_length
327 will return the sum of the actual length for all
328 transferred USB frames for the given USB transfer.
332 .Fn libusb20_tr_get_max_frames
333 will return the maximum number of USB frames that were
334 allocated when an USB transfer was setup for the given USB transfer.
338 .Fn libusb20_tr_get_max_packet_length
339 will return the maximum packet length in bytes
340 associated with the given USB transfer.
342 The packet length can be used round up buffer sizes so that short USB
343 packets are avoided for proxy buffers.
348 .Fn libusb20_tr_get_max_total_length
349 will return the maximum value for the data length sum of all USB
350 frames associated with an USB transfer.
351 In case of control transfers the value returned does not include the
352 length of the SETUP packet, 8 bytes, which is part of frame zero.
353 The returned value of this function is always aligned to the maximum
354 packet size, wMaxPacketSize, of the endpoint which the USB transfer is
359 .Fn libusb20_tr_get_status
360 will return the status of an USB transfer.
362 Status values are defined by a set of LIBUSB20_TRANSFER_XXX enums.
366 .Fn libusb20_tr_pending
367 will return non-zero if the given USB transfer is
368 pending for completion.
370 Else this function returns zero.
374 .Fn libusb20_tr_callback_wrapper
375 This is an internal function used to wrap asynchronous USB callbacks.
379 .Fn libusb20_tr_clear_stall_sync
380 This is an internal function used to synchronously clear the stall on
381 the given USB transfer.
383 Please see the USB specification for more information on stall
386 If the given USB transfer is pending when this function is called, the
387 USB transfer will complete with an error after that this function has
392 .Fn libusb20_tr_drain
393 will stop the given USB transfer and will not return
394 until the USB transfer has been stopped in hardware.
398 .Fn libusb20_tr_set_buffer
401 pointer for the given USB transfer and
404 Typically the frame index is zero.
409 .Fn libusb20_tr_set_callback
410 is used to set the USB callback for asynchronous USB
413 The callback type is defined by libusb20_tr_callback_t.
417 .Fn libusb20_tr_set_flags
418 is used to set various USB flags for the given USB transfer.
419 .Bl -tag -width "LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK"
420 .It LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK
421 Report a short frame as error.
422 .It LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK
423 Multiple short frames are not allowed.
424 .It LIBUSB20_TRANSFER_FORCE_SHORT
425 All transmitted frames are short terminated.
426 .It LIBUSB20_TRANSFER_DO_CLEAR_STALL
427 Will do a clear-stall before starting the transfer.
432 .Fn libusb20_tr_get_length
433 returns the length of the given USB frame by index.
434 After an USB transfer is complete the USB frame length will get updated to the actual transferred length.
438 .Fn libusb20_tr_set_length
439 sets the length of the given USB frame by index.
443 .Fn libusb20_tr_set_priv_sc0
444 sets private driver pointer number zero.
448 .Fn libusb20_tr_set_priv_sc1
449 sets private driver pointer number one.
453 .Fn libusb20_tr_set_timeout
454 sets the timeout for the given USB transfer.
456 A timeout value of zero means no timeout.
458 The timeout is given in milliseconds.
462 .Fn libusb20_tr_set_total_frames
463 sets the total number of frames that should be executed when the USB transfer is submitted.
465 The total number of USB frames must be less than the maximum number of USB frames associated with the given USB transfer.
469 .Fn libusb20_tr_setup_bulk
470 is a helper function for setting up a single frame USB BULK transfer.
474 .Fn libusb20_tr_setup_control
475 is a helper function for setting up a single or dual
476 frame USB CONTROL transfer depending on the control transfer length.
480 .Fn libusb20_tr_setup_intr
481 is a helper function for setting up a single frame USB INTERRUPT transfer.
485 .Fn libusb20_tr_setup_isoc
486 is a helper function for setting up a multi frame USB ISOCHRONOUS transfer.
490 .Fn libusb20_tr_bulk_intr_sync
491 will perform a synchronous BULK or INTERRUPT transfer having length given by the
493 argument and buffer pointer given by the
495 argument on the USB transfer given by the
501 argument is non-NULL the actual transfer length will be stored at the given pointer destination.
505 argument is non-zero the transfer will timeout after the given value in milliseconds.
507 This function does not change the transfer flags, like short packet not ok.
509 This function returns zero on success else a LIBUSB20_TRANSFER_XXX value is returned.
513 .Fn libusb20_tr_start
514 will get the USB transfer started, if not already
517 This function will not get the transfer queued in hardware.
519 This function is non-blocking.
524 will get the USB transfer stopped, if not already stopped.
526 This function is non-blocking, which means that the actual stop can
527 happen after the return of this function.
531 .Fn libusb20_tr_submit
532 will get the USB transfer queued in hardware.
537 .Fn libusb20_tr_get_priv_sc0
538 returns private driver pointer number zero associated
539 with an USB transfer.
544 .Fn libusb20_tr_get_priv_sc1
545 returns private driver pointer number one associated
546 with an USB transfer.
549 .Sh USB DEVICE OPERATIONS
552 .Fn libusb20_dev_get_backend_name
553 returns a zero terminated string describing the backend used.
557 .Fn libusb20_dev_get_port_path
558 retrieves the list of USB port numbers which the datastream for a given USB device follows.
559 The first port number is the Root HUB port number.
560 Then children port numbers follow.
561 The Root HUB device itself has a port path length of zero.
562 Valid port numbers start at one and range until and including 255.
563 Typically there should not be more than 16 levels, due to electrical and protocol limitations.
564 This functions returns the number of actual port levels upon success
565 else a LIBUSB20_ERROR value is returned which are always negative.
566 If the actual number of port levels is greater than the maximum
567 specified, a LIBUSB20_ERROR value is returned.
571 .Fn libusb20_dev_get_info
572 retrieves the BSD specific usb_device_info structure into the memory location given by
574 The USB device given by
576 must be opened before this function will succeed.
577 This function returns zero on success else a LIBUSB20_ERROR value is returned.
581 .Fn libusb20_dev_get_iface_desc
582 retrieves the kernel interface description for the given USB
584 The format of the USB interface description is: "drivername<unit>: <description>"
585 The description string is always zero terminated.
586 A zero length string is written in case no driver is attached to the given interface.
587 The USB device given by
589 must be opened before this function will succeed.
590 This function returns zero on success else a LIBUSB20_ERROR value is returned.
594 .Fn libusb20_dev_get_desc
595 returns a zero terminated string describing the given USB device.
596 The format of the string is: "drivername<unit>: <description>"
600 .Fn libusb20_dev_close
601 will close the given USB device.
603 This function returns zero on success else a LIBUSB20_ERROR value is
608 .Fn libusb20_dev_detach_kernel_driver
609 will try to detach the kernel driver for the USB interface given by
612 This function returns zero on success else a LIBUSB20_ERROR value is
617 .Fn libusb20_dev_set_config_index
618 will try to set the configuration index on an USB
621 The first configuration index is zero.
623 The un-configure index is 255.
625 This function returns zero on success else a LIBUSB20_ERROR value is returned.
629 .Fn libusb20_dev_get_debug
630 returns the debug level of an USB device.
634 .Fn libusb20_dev_get_fd
635 returns the file descriptor of the given USB device.
637 A negative value is returned when no file descriptor is present.
639 The file descriptor can be used for polling purposes.
643 .Fn libusb20_dev_kernel_driver_active
644 returns zero if a kernel driver is active on the given USB interface.
646 Else a LIBUSB20_ERROR value is returned.
650 .Fn libusb20_dev_open
651 opens an USB device so that setting up USB transfers
654 The number of USB transfers can be zero which means only control
655 transfers are allowed.
657 This function returns zero on success else a LIBUSB20_ERROR value is
660 A return value of LIBUSB20_ERROR_BUSY means that the device is already
665 .Fn libusb20_dev_process
666 is called to sync kernel USB transfers with userland USB
669 This function returns zero on success else a LIBUSB20_ERROR value is
670 returned typically indicating that the given USB device has been
675 .Fn libusb20_dev_request_sync
676 will perform a synchronous control request on the given
679 Before this call will succeed the USB device must be opened.
682 is a pointer to a decoded and host endian SETUP packet.
684 is a pointer to a data transfer buffer associated with the control transaction. This argument can be NULL.
686 is a pointer to a variable that will hold the actual transfer length after the control transaction is complete.
688 is the transaction timeout given in milliseconds.
689 A timeout of zero means no timeout.
691 is used to specify transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK.
693 This function returns zero on success else a LIBUSB20_ERROR value is
698 .Fn libusb20_dev_req_string_sync
699 will synchronously request an USB string by language ID
700 and string index into the given buffer limited by a maximum length.
702 This function returns zero on success else a LIBUSB20_ERROR value is
707 .Fn libusb20_dev_req_string_simple_sync
708 will synchronously request an USB string using the
709 default language ID and convert the string into ASCII before storing
710 the string into the given buffer limited by a maximum length which
711 includes the terminating zero.
713 This function returns zero on success else a LIBUSB20_ERROR value is
719 .Fn libusb20_dev_reset
720 will try to BUS reset the given USB device and restore
721 the last set USB configuration.
723 This function returns zero on success else a LIBUSB20_ERROR value is
729 .Fn libusb20_dev_check_connected
730 will check if an opened USB device is still connected.
732 This function returns zero if the device is still connected else a LIBUSB20_ERROR value is returned.
737 .Fn libusb20_dev_set_power_mode
738 sets the power mode of the USB device.
741 .Bl -tag -width "LIBUSB20_POWER_OFF"
742 .It LIBUSB20_POWER_OFF
743 .It LIBUSB20_POWER_ON
744 .It LIBUSB20_POWER_SAVE
745 .It LIBUSB20_POWER_SUSPEND
746 .It LIBUSB20_POWER_RESUME
750 This function returns zero on success else a LIBUSB20_ERROR value is
755 .Fn libusb20_dev_get_power_mode
756 returns the currently selected power mode for the given
761 .Fn libusb20_dev_get_power_usage
762 returns the reported power usage in milliamps for the given USB device.
763 A power usage of zero typically means that the device is self powered.
767 .Fn libusb20_dev_set_alt_index
768 will try to set the given alternate index for the given
771 This function returns zero on success else a LIBUSB20_ERROR value is
776 .Fn libusb20_dev_get_device_desc
777 returns a pointer to the decoded and host endian version
778 of the device descriptor.
780 The USB device need not be opened when calling this function.
784 .Fn libusb20_dev_alloc_config
785 will read out and decode the USB config descriptor for
786 the given USB device and config index. This function returns a pointer
787 to the decoded configuration which must eventually be passed to
788 free(). NULL is returned in case of failure.
792 .Fn libusb20_dev_alloc
793 is an internal function to allocate a new USB device.
797 .Fn libusb20_dev_get_address
798 returns the internal and not necessarily the real
799 hardware address of the given USB device.
800 Valid addresses start at one.
804 .Fn libusb20_dev_get_parent_address
805 returns the internal and not necessarily the real hardware address of
806 the given parent USB HUB device.
807 This value is zero for the root HUB which usually has a device address
809 Valid addresses start at one.
813 .Fn libusb20_dev_get_parent_port
814 returns the port number on the parent USB HUB device.
815 This value is zero for the root HUB which usually has a device address
817 Valid port numbers start at one.
821 .Fn libusb20_dev_get_bus_number
822 returns the internal bus number which the given USB
824 Valid bus numbers start at zero.
828 .Fn libusb20_dev_get_mode
829 returns the current operation mode of the USB entity.
831 Valid return values are:
832 .Bl -tag -width "LIBUSB20_MODE_DEVICE"
833 .It LIBUSB20_MODE_HOST
834 .It LIBUSB20_MODE_DEVICE
839 .Fn libusb20_dev_get_speed
840 returns the current speed of the given USB device.
842 .Bl -tag -width "LIBUSB20_SPEED_VARIABLE"
843 .It LIBUSB20_SPEED_UNKNOWN
844 .It LIBUSB20_SPEED_LOW
845 .It LIBUSB20_SPEED_FULL
846 .It LIBUSB20_SPEED_HIGH
847 .It LIBUSB20_SPEED_VARIABLE
848 .It LIBUSB20_SPEED_SUPER
853 .Fn libusb20_dev_get_config_index
854 returns the currently selected config index for the given
859 .Fn libusb20_dev_free
860 will free the given USB device and all associated USB
865 .Fn libusb20_dev_set_debug
866 will set the debug level for the given USB device.
870 .Fn libusb20_dev_wait_process
871 will wait until a pending USB transfer has completed on
872 the given USB device.
874 A timeout value can be specified which is passed on to the
878 .Sh USB BACKEND OPERATIONS
880 .Fn libusb20_be_get_template
881 will return the currently selected global USB device
882 side mode template into the integer pointer
884 This function returns zero on success else a LIBUSB20_ERROR value is
889 .Fn libusb20_be_set_template
890 will set the global USB device side mode template to
892 The new template is not activated until after the next USB
894 The template number decides how the USB device will present itself to
895 the USB Host, like Mass Storage Device, USB Ethernet Device. Also see
899 This function returns zero on success else a LIBUSB20_ERROR value is
904 .Fn libusb20_be_get_dev_quirk
905 will return the device quirk according to
907 into the libusb20_quirk structure pointed to by
909 This function returns zero on success else a LIBUSB20_ERROR value is
912 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
917 .Fn libusb20_be_get_quirk_name
918 will return the quirk name according to
920 into the libusb20_quirk structure pointed to by
922 This function returns zero on success else a LIBUSB20_ERROR value is
925 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
930 .Fn libusb20_be_add_dev_quirk
931 will add the libusb20_quirk structure pointed to by the
933 argument into the device quirk list.
935 This function returns zero on success else a LIBUSB20_ERROR value is
938 If the given quirk cannot be added LIBUSB20_ERROR_NO_MEM is
943 .Fn libusb20_be_remove_dev_quirk
944 will remove the quirk matching the libusb20_quirk structure pointed to by the
946 argument from the device quirk list.
948 This function returns zero on success else a LIBUSB20_ERROR value is
951 If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
956 .Fn libusb20_be_alloc_default
957 .Fn libusb20_be_alloc_freebsd
958 .Fn libusb20_be_alloc_linux
959 These functions are used to allocate a specific USB backend or the
960 operating system default USB backend. Allocating a backend is a way to
961 scan for currently present USB devices.
965 .Fn libusb20_be_device_foreach
966 is used to iterate USB devices present in a USB backend.
968 The starting value of
972 This function returns the next USB device in the list.
974 If NULL is returned the end of the USB device list has been reached.
978 .Fn libusb20_be_dequeue_device
979 will dequeue the given USB device pointer from the
980 backend USB device list.
982 Dequeued USB devices will not be freed when the backend is freed.
986 .Fn libusb20_be_enqueue_device
987 will enqueue the given USB device pointer in the backend USB device list.
989 Enqueued USB devices will get freed when the backend is freed.
994 will free the given backend and all USB devices in its device list.
997 .Sh USB DESCRIPTOR PARSING
999 .Fn libusb20_me_get_1 pie offset
1000 This function will return a byte at the given byte offset of a message
1003 This function is safe against invalid offsets.
1007 .Fn libusb20_me_get_2 pie offset
1008 This function will return a little endian 16-bit value at the given byte offset of a message
1011 This function is safe against invalid offsets.
1015 .Fn libusb20_me_encode pbuf len pdecoded
1016 This function will encode a so-called *DECODED structure into binary
1019 The total encoded length that will fit in the given buffer is
1022 If the buffer pointer is NULL no data will be written to the buffer
1027 .Fn libusb20_me_decode pbuf len pdecoded
1028 This function will decode a binary structure into a so-called *DECODED
1031 The total decoded length is returned.
1033 The buffer pointer cannot be NULL.
1038 .Fn libusb20_strerror "int code"
1039 Get the ASCII representation of the error given by the
1042 This function does not return NULL.
1045 .Fn libusb20_error_name "int code"
1046 Get the ASCII representation of the error enum given by the
1049 This function does not return NULL.
1067 API derives from the libusb project at sourceforge.