usb4bsd: Pull up libusb and usbcontrol to FreeBSD current's.
[dragonfly.git] / lib / libusb / libusb.3
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1.\"
2.\" Copyright (c) 2009 Sylvestre Gallon
3.\"
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5.\"
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aa3e5c14 27.\" $FreeBSD: src/lib/libusb/libusb.3,v 1.27 2012/05/11 20:06:46 gjb Exp $
1d96047e 28.\"
aa3e5c14 29.Dd October 14, 2012
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30.Dt LIBUSB 3
31.Os
32.Sh NAME
33.Nm libusb
34.Nd "USB access library"
35.Sh LIBRARY
36USB access library
37.Pq libusb, -lusb
38.Sh SYNOPSIS
39.In libusb.h
40.Sh DESCRIPTION
41The
42.Nm
43library contains interfaces for directly managing a usb device.
44The current implementation supports v1.0 of the libusb API.
45.Sh LIBRARY INITIALISATION / DEINITIALISATION
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46.Ft int
47.Fn libusb_init libusb_context **ctx
48This function initialises libusb.
49It must be called at the beginning
50of the program, before other libusb routines are used.
51This function returns 0 on success or LIBUSB_ERROR on
52failure.
53.Pp
54.Ft void
55.Fn libusb_exit "libusb_context *ctx"
56Deinitialise libusb.
57Must be called at the end of the application.
58Other libusb routines may not be called after this function.
59.Pp
60.Ft const char *
61.Fn libusb_strerror "int code"
62Get the ASCII representation of the error given by the
63.Fa code
64argument.
65This function does not return NULL.
66.Pp
67.Ft const char *
68.Fn libusb_error_name "int code"
69Get the ASCII representation of the error enum given by the
70.Fa code
71argument.
72This function does not return NULL.
73.Pp
74.Ft void
75.Fn libusb_set_debug "libusb_context *ctx" "int level"
76Set the debug level to
77.Fa level .
78.Pp
79.Ft ssize_t
80.Fn libusb_get_device_list "libusb_context *ctx" "libusb_device ***list"
81Populate
82.Fa list
83with the list of usb devices available, adding a reference to each
84device in the list.
85All the list entries created by this
86function must have their reference counter
87decremented when you are done with them,
88and the list itself must be freed.
89This
90function returns the number of devices in the list or a LIBUSB_ERROR code.
91.Pp
92.Ft void
93.Fn libusb_free_device_list "libusb_device **list" "int unref_devices"
94Free the list of devices discovered by libusb_get_device_list.
95If
96.Fa unref_device
97is set to 1 all devices in the list have their reference
98counter decremented once.
99.Pp
100.Ft uint8_t
101.Fn libusb_get_bus_number "libusb_device *dev"
102Returns the number of the bus contained by the device
aa3e5c14 103.Fa dev .
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104.Pp
105.Ft uint8_t
106.Fn libusb_get_device_address "libusb_device *dev"
107Returns the device_address contained by the device
aa3e5c14 108.Fa dev .
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109.Pp
110.Ft enum libusb_speed
111.Fn libusb_get_device_speed "libusb_device *dev"
112Returns the wire speed at which the device is connected.
113See the LIBUSB_SPEED_XXX enums for more information.
114LIBUSB_SPEED_UNKNOWN is returned in case of unknown wire speed.
115.Pp
116.Ft int
117.Fn libusb_get_max_packet_size "libusb_device *dev" "unsigned char endpoint"
118Returns the wMaxPacketSize value on success, LIBUSB_ERROR_NOT_FOUND if the
119endpoint does not exist and LIBUSB_ERROR_OTHERS on other failure.
120.Pp
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121.Ft int
122.Fn libusb_get_max_iso_packet_size "libusb_device *dev" "unsigned char endpoint"
123Returns the packet size multiplied by the packet multiplier on success,
124LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist and
125LIBUSB_ERROR_OTHERS on other failure.
126.Pp
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127.Ft libusb_device *
128.Fn libusb_ref_device "libusb_device *dev"
129Increment the reference counter of the device
aa3e5c14 130.Fa dev .
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131.Pp
132.Ft void
133.Fn libusb_unref_device "libusb_device *dev"
134Decrement the reference counter of the device
aa3e5c14 135.Fa dev .
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136.Pp
137.Ft int
138.Fn libusb_open "libusb_device *dev" "libusb_device_handle **devh"
139Open a device and obtain a device_handle.
140Returns 0 on success,
141LIBUSB_ERROR_NO_MEM on memory allocation problems, LIBUSB_ERROR_ACCESS
142on permissions problems, LIBUSB_ERROR_NO_DEVICE if the device has been
143disconnected and a LIBUSB_ERROR code on other errors.
144.Pp
145.Ft libusb_device_handle *
146.Fn libusb_open_device_with_vid_pid "libusb_context *ctx" "uint16_t vid" "uint16_t pid"
147A convenience function to open a device by vendor and product IDs
148.Fa vid
149and
aa3e5c14 150.Fa pid .
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151Returns NULL on error.
152.Pp
153.Ft void
154.Fn libusb_close "libusb_device_handle *devh"
155Close a device handle.
156.Pp
157.Ft libusb_device *
158.Fn libusb_get_device "libusb_device_handle *devh"
159Get the device contained by devh.
160Returns NULL on error.
161.Pp
162.Ft int
163.Fn libusb_get_configuration "libusb_device_handle *devh" "int *config"
aa3e5c14 164Returns the value of the current configuration.
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165Returns 0
166on success, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
167and a LIBUSB_ERROR code on error.
168.Pp
169.Ft int
170.Fn libusb_set_configuration "libusb_device_handle *devh" "int config"
171Set the active configuration to
172.Fa config
173for the device contained by
aa3e5c14 174.Fa devh .
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175This function returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the requested
176configuration does not exist, LIBUSB_ERROR_BUSY if the interfaces are currently
177claimed, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and a
178LIBUSB_ERROR code on failure.
179.Pp
180.Ft int
181.Fn libusb_claim_interface "libusb_device_handle *devh" "int interface_number"
182Claim an interface in a given libusb_handle
aa3e5c14 183.Fa devh .
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184This is a non-blocking function.
185It returns 0 on success, LIBUSB_ERROR_NOT_FOUND
186if the requested interface does not exist, LIBUSB_ERROR_BUSY if a program or
187driver has claimed the interface, LIBUSB_ERROR_NO_DEVICE if the device has
188been disconnected and a LIBUSB_ERROR code on failure.
189.Pp
190.Ft int
191.Fn libusb_release_interface "libusb_device_handle *devh" "int interface_number"
192This function releases an interface.
193All the claimed interfaces on a device must be released
194before closing the device.
195Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the
196interface was not claimed, LIBUSB_ERROR_NO_DEVICE if the device has been
197disconnected and LIBUSB_ERROR on failure.
198.Pp
199.Ft int
200.Fn libusb_set_interface_alt_setting "libusb_device_handle *dev" "int interface_number" "int alternate_setting"
201Activate an alternate setting for an interface.
202Returns 0 on success,
203LIBUSB_ERROR_NOT_FOUND if the interface was not claimed or the requested
204setting does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been
205disconnected and a LIBUSB_ERROR code on failure.
206.Pp
207.Ft int
208.Fn libusb_clear_halt "libusb_device_handle *devh" "unsigned char endpoint"
209Clear an halt/stall for a endpoint.
210Returns 0 on success, LIBUSB_ERROR_NOT_FOUND
211if the endpoint does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been
212disconnected and a LIBUSB_ERROR code on failure.
213.Pp
214.Ft int
215.Fn libusb_reset_device "libusb_device_handle *devh"
216Perform an USB port reset for an usb device.
217Returns 0 on success,
218LIBUSB_ERROR_NOT_FOUND if re-enumeration is required or if the device has
219been disconnected and a LIBUSB_ERROR code on failure.
220.Pp
221.Ft int
222.Fn libusb_check_connected "libusb_device_handle *devh"
223Test if the USB device is still connected.
224Returns 0 on success,
225LIBUSB_ERROR_NO_DEVICE if it has been disconnected and a LIBUSB_ERROR
226code on failure.
227.Pp
228.Ft int
229.Fn libusb_kernel_driver_active "libusb_device_handle *devh" "int interface"
230Determine if a driver is active on a interface.
231Returns 0 if no kernel driver is active
232and 1 if a kernel driver is active, LIBUSB_ERROR_NO_DEVICE
233if the device has been disconnected and a LIBUSB_ERROR code on failure.
234.Pp
235.Ft int
236.Fn libusb_get_driver "libusb_device_handle *devh" "int interface" "char *name" "int namelen"
237or
238.Ft int
239.Fn libusb_get_driver_np "libusb_device_handle *devh" "int interface" "char *name" "int namelen"
240Copy the name of the driver attached to the given
241.Fa device
242and
243.Fa interface
244into the buffer
245.Fa name
246of length
247.Fa namelen .
248Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if no kernel driver is attached
249to the given interface and LIBUSB_ERROR_INVALID_PARAM if the interface does
250not exist.
251This function is non-portable.
252The buffer pointed to by
253.Fa name
254is only zero terminated on success.
255.Pp
256.Ft int
257.Fn libusb_detach_kernel_driver "libusb_device_handle *devh" "int interface"
258or
259.Ft int
260.Fn libusb_detach_kernel_driver_np "libusb_device_handle *devh" "int interface"
261Detach a kernel driver from an interface.
262This is needed to claim an interface already claimed by a kernel driver.
263Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if no kernel driver was active,
264LIBUSB_ERROR_INVALID_PARAM if the interface does not exist,
265LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
266and a LIBUSB_ERROR code on failure.
267This function is non-portable.
268.Pp
269.Ft int
270.Fn libusb_attach_kernel_driver "libusb_device_handle *devh" "int interface"
271Re-attach an interface kernel driver that was previously detached.
272Returns 0 on success,
273LIBUSB_ERROR_INVALID_PARAM if the interface does not exist,
274LIBUSB_ERROR_NO_DEVICE
275if the device has been disconnected, LIBUSB_ERROR_BUSY if the driver cannot be
276attached because the interface is claimed by a program or driver and a
277LIBUSB_ERROR code on failure.
1d96047e 278.Sh USB DESCRIPTORS
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279.Ft int
280.Fn libusb_get_device_descriptor "libusb_device *dev" "libusb_device_descriptor *desc"
281Get the USB device descriptor for the device
aa3e5c14 282.Fa dev .
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283This is a non-blocking function.
284Returns 0 on success and a LIBUSB_ERROR code on
285failure.
286.Pp
287.Ft int
aa3e5c14 288.Fn libusb_get_active_config_descriptor "libusb_device *dev" "struct libusb_config_descriptor **config"
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289Get the USB configuration descriptor for the active configuration.
290Returns 0 on
291success, LIBUSB_ERROR_NOT_FOUND if the device is in
292an unconfigured state
293and a LIBUSB_ERROR code on error.
294.Pp
295.Ft int
296.Fn libusb_get_config_descriptor "libusb_device *dev" "uint8_t config_index" "libusb_config_descriptor **config"
297Get a USB configuration descriptor based on its index
298.Fa idx.
299Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
300and a LIBUSB_ERROR code on error.
301.Pp
302.Ft int
303.Fn libusb_get_config_descriptor_by_value "libusb_device *dev" "uint8 bConfigurationValue" "libusb_config_descriptor **config"
304Get a USB configuration descriptor with a specific bConfigurationValue.
305This is
306a non-blocking function which does not send a request through the device.
307Returns 0
308on success, LIBUSB_ERROR_NOT_FOUND if the configuration
309does not exist and a
310LIBUSB_ERROR code on failure.
311.Pp
312.Ft void
313.Fn libusb_free_config_descriptor "libusb_config_descriptor *config"
314Free a configuration descriptor.
315.Pp
316.Ft int
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317.Fn libusb_get_string_descriptor "libusb_device_handle *devh" "uint8_t desc_idx" "uint16_t langid" "unsigned char *data" "int length"
318Retrieve a string descriptor in raw format.
319Returns the number of bytes actually transferred on success
320or a negative LIBUSB_ERROR code on failure.
321.Pp
322.Ft int
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323.Fn libusb_get_string_descriptor_ascii "libusb_device_handle *devh" "uint8_t desc_idx" "unsigned char *data" "int length"
324Retrieve a string descriptor in C style ASCII.
325Returns the positive number of bytes in the resulting ASCII string
326on success and a LIBUSB_ERROR code on failure.
327.Pp
328.Ft int
329.Fn libusb_parse_ss_endpoint_comp "const void *buf" "int len" "libusb_ss_endpoint_companion_descriptor **ep_comp"
330This function parses the USB 3.0 endpoint companion descriptor in host endian format pointed to by
331.Fa buf
332and having a length of
aa3e5c14 333.Fa len .
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334Typically these arguments are the extra and extra_length fields of the
335endpoint descriptor.
336On success the pointer to resulting descriptor is stored at the location given by
aa3e5c14 337.Fa ep_comp .
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338Returns zero on success and a LIBUSB_ERROR code on failure.
339On success the parsed USB 3.0 endpoint companion descriptor must be
340freed using the libusb_free_ss_endpoint_comp function.
341.Pp
342.Ft void
343.Fn libusb_free_ss_endpoint_comp "libusb_ss_endpoint_companion_descriptor *ep_comp"
344This function is NULL safe and frees a parsed USB 3.0 endpoint companion descriptor.
345.Pp
346.Ft int
347.Fn libusb_parse_bos_descriptor "const void *buf" "int len" "libusb_bos_descriptor **bos"
348This function parses a Binary Object Store, BOS, descriptor into host endian format pointed to by
349.Fa buf
350and having a length of
aa3e5c14 351.Fa len .
1d96047e 352On success the pointer to resulting descriptor is stored at the location given by
aa3e5c14 353.Fa bos .
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354Returns zero on success and a LIBUSB_ERROR code on failure.
355On success the parsed BOS descriptor must be freed using the
356libusb_free_bos_descriptor function.
357.Pp
358.Ft void
359.Fn libusb_free_bos_descriptor "libusb_bos_descriptor *bos"
360This function is NULL safe and frees a parsed BOS descriptor.
1d96047e 361.Sh USB ASYNCHRONOUS I/O
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362.Ft struct libusb_transfer *
363.Fn libusb_alloc_transfer "int iso_packets"
364Allocate a transfer with the number of isochronous packet descriptors
365specified by
366.Fa iso_packets .
367Returns NULL on error.
368.Pp
369.Ft void
370.Fn libusb_free_transfer "struct libusb_transfer *tr"
371Free a transfer.
372.Pp
373.Ft int
374.Fn libusb_submit_transfer "struct libusb_transfer *tr"
375This function will submit a transfer and returns immediately.
376Returns 0 on success, LIBUSB_ERROR_NO_DEVICE if
377the device has been disconnected and a
378LIBUSB_ERROR code on other failure.
379.Pp
380.Ft int
381.Fn libusb_cancel_transfer "struct libusb_transfer *tr"
382This function asynchronously cancels a transfer.
383Returns 0 on success and a LIBUSB_ERROR code on failure.
1d96047e 384.Sh USB SYNCHRONOUS I/O
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385.Ft int
386.Fn libusb_control_transfer "libusb_device_handle *devh" "uint8_t bmRequestType" "uint8_t bRequest" "uint16_t wValue" "uint16_t wIndex" "unsigned char *data" "uint16_t wLength" "unsigned int timeout"
387Perform a USB control transfer.
388Returns the actual number of bytes
389transferred on success, in the range from and including zero up to and
390including
391.Fa wLength .
392On error a LIBUSB_ERROR code is returned, for example
393LIBUSB_ERROR_TIMEOUT if the transfer timed out, LIBUSB_ERROR_PIPE if the
394control request was not supported, LIBUSB_ERROR_NO_DEVICE if the
395device has been disconnected and another LIBUSB_ERROR code on other failures.
396The LIBUSB_ERROR codes are all negative.
397.Pp
398.Ft int
399.Fn libusb_bulk_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout"
400Perform an USB bulk transfer.
401A timeout value of zero means no timeout.
402The timeout value is given in milliseconds.
403Returns 0 on success, LIBUSB_ERROR_TIMEOUT
404if the transfer timed out, LIBUSB_ERROR_PIPE if the control request was not
405supported, LIBUSB_ERROR_OVERFLOW if the device offered more data,
406LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and
407a LIBUSB_ERROR code on other failure.
408.Pp
409.Ft int
410.Fn libusb_interrupt_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout"
411Perform an USB Interrupt transfer.
412A timeout value of zero means no timeout.
413The timeout value is given in milliseconds.
414Returns 0 on success, LIBUSB_ERROR_TIMEOUT
415if the transfer timed out, LIBUSB_ERROR_PIPE if the control request was not
416supported, LIBUSB_ERROR_OVERFLOW if the device offered more data,
417LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and
418a LIBUSB_ERROR code on other failure.
1d96047e 419.Sh USB EVENTS
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420.Ft int
421.Fn libusb_try_lock_events "libusb_context *ctx"
422Try to acquire the event handling lock.
423Returns 0 if the lock was obtained and 1 if not.
424.Pp
425.Ft void
426.Fn libusb_lock_events "libusb_context *ctx"
427Acquire the event handling lock.
428This function is blocking.
429.Pp
430.Ft void
431.Fn libusb_unlock_events "libusb_context *ctx"
432Release the event handling lock.
433This will wake up any thread blocked
434on
aa3e5c14 435.Fn libusb_wait_for_event .
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436.Pp
437.Ft int
438.Fn libusb_event_handling_ok "libusb_context *ctx"
439Determine if it still OK for this thread to be doing event handling.
440Returns 1
441if event handling can start or continue.
442Returns 0 if this thread must give up
443the events lock.
444.Pp
445.Ft int
446.Fn libusb_event_handler_active "libusb_context *ctx"
447Determine if an active thread is handling events.
448Returns 1 if there is a thread handling events and 0 if there
449are no threads currently handling events.
450.Pp
451.Ft void
452.Fn libusb_lock_event_waiters "libusb_context *ctx"
453Acquire the event_waiters lock.
454This lock is designed to be obtained in the
455situation where you want to be aware when events are completed, but some other
456thread is event handling so calling libusb_handle_events() is not allowed.
457.Pp
458.Ft void
459.Fn libusb_unlock_event_waiters "libusb_context *ctx"
460Release the event_waiters lock.
461.Pp
462.Ft int
463.Fn libusb_wait_for_event "libusb_context *ctx" "struct timeval *tv"
464Wait for another thread to signal completion of an event.
465Must be called
466with the event waiters lock held, see libusb_lock_event_waiters().
467This will
468block until the timeout expires or a transfer completes or a thread releases
469the event handling lock through libusb_unlock_events().
470Returns 0 after a
471transfer completes or another thread stops event handling, and 1 if the
472timeout expired.
473.Pp
474.Ft int
475.Fn libusb_handle_events_timeout "libusb_context *ctx" "struct timeval *tv"
476Handle any pending events by checking if timeouts have expired and by
477checking the set of file descriptors for activity.
478Returns 0 on success, or a
479LIBUSB_ERROR code on failure.
480.Pp
481.Ft int
482.Fn libusb_handle_events "libusb_context *ctx"
483Handle any pending events in blocking mode with a sensible timeout.
484Returns 0
485on success and a LIBUSB_ERROR code on failure.
486.Pp
487.Ft int
488.Fn libusb_handle_events_locked "libusb_context *ctx" "struct timeval *tv"
aa3e5c14 489Handle any pending events by polling file descriptors, without checking if
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490another thread is already doing so.
491Must be called with the event lock held.
492.Pp
493.Ft int
494.Fn libusb_get_next_timeout "libusb_context *ctx" "struct timeval *tv"
495Determine the next internal timeout that libusb needs to handle.
496Returns 0
497if there are no pending timeouts, 1 if a timeout was returned, or a LIBUSB_ERROR
498code on failure.
499.Pp
500.Ft void
501.Fn libusb_set_pollfd_notifiers "libusb_context *ctx" "libusb_pollfd_added_cb added_cb" "libusb_pollfd_removed_cb remove_cb" "void *user_data"
502Register notification functions for file descriptor additions/removals.
503These functions will be invoked for every new or removed file descriptor
504that libusb uses as an event source.
505.Pp
506.Ft const struct libusb_pollfd **
507.Fn libusb_get_pollfds "libusb_context *ctx"
508Retrive a list of file descriptors that should be polled by your main loop as
509libusb event sources.
510Returns a NULL-terminated list on success or NULL on failure.
511.Sh LIBUSB VERSION 0.1 COMPATIBILITY
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512The library is also compliant with LibUSB version 0.1.12.
513.Pp
514.Fn usb_open
515.Fn usb_close
516.Fn usb_get_string
517.Fn usb_get_string_simple
518.Fn usb_get_descriptor_by_endpoint
519.Fn usb_get_descriptor
520.Fn usb_parse_descriptor
521.Fn usb_parse_configuration
522.Fn usb_destroy_configuration
523.Fn usb_fetch_and_parse_descriptors
524.Fn usb_bulk_write
525.Fn usb_bulk_read
526.Fn usb_interrupt_write
527.Fn usb_interrupt_read
528.Fn usb_control_msg
529.Fn usb_set_configuration
530.Fn usb_claim_interface
531.Fn usb_release_interface
532.Fn usb_set_altinterface
533.Fn usb_resetep
534.Fn usb_clear_halt
535.Fn usb_reset
536.Fn usb_strerror
537.Fn usb_init
538.Fn usb_set_debug
539.Fn usb_find_busses
540.Fn usb_find_devices
541.Fn usb_device
542.Fn usb_get_busses
543.Fn usb_check_connected
544.Fn usb_get_driver_np
545.Fn usb_detach_kernel_driver_np
546.Sh SEE ALSO
547.Xr libusb20 3 ,
548.Xr usb 4 ,
549.Xr usbconfig 8 ,
550.Xr usbdump 8
551.Pp
552.Pa http://libusb.sourceforge.net/
553.Sh HISTORY
554.Nm
555support first appeared in
556.Fx 8.0 .