libusb{,20}.3: Add libusb to mdoc.local and adjust LIBRARY section.
[dragonfly.git] / lib / libusb / libusb.3
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2.\" Copyright (c) 2009 Sylvestre Gallon
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9b0c1abe 27.\" $FreeBSD: head/lib/libusb/libusb.3 260315 2014-01-05 10:41:43Z hselasky $
1d96047e 28.\"
9b0c1abe 29.Dd January 5, 2014
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30.Dt LIBUSB 3
31.Os
32.Sh NAME
33.Nm libusb
34.Nd "USB access library"
35.Sh LIBRARY
a340784f 36.Lb libusb
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37.Sh SYNOPSIS
38.In libusb.h
39.Sh DESCRIPTION
40The
41.Nm
42library contains interfaces for directly managing a usb device.
43The current implementation supports v1.0 of the libusb API.
44.Sh LIBRARY INITIALISATION / DEINITIALISATION
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45.Ft int
46.Fn libusb_init libusb_context **ctx
47This function initialises libusb.
48It must be called at the beginning
49of the program, before other libusb routines are used.
50This function returns 0 on success or LIBUSB_ERROR on
51failure.
52.Pp
53.Ft void
54.Fn libusb_exit "libusb_context *ctx"
55Deinitialise libusb.
56Must be called at the end of the application.
57Other libusb routines may not be called after this function.
58.Pp
59.Ft const char *
60.Fn libusb_strerror "int code"
61Get the ASCII representation of the error given by the
62.Fa code
63argument.
64This function does not return NULL.
65.Pp
66.Ft const char *
67.Fn libusb_error_name "int code"
68Get the ASCII representation of the error enum given by the
69.Fa code
70argument.
71This function does not return NULL.
72.Pp
73.Ft void
74.Fn libusb_set_debug "libusb_context *ctx" "int level"
75Set the debug level to
76.Fa level .
77.Pp
78.Ft ssize_t
79.Fn libusb_get_device_list "libusb_context *ctx" "libusb_device ***list"
80Populate
81.Fa list
82with the list of usb devices available, adding a reference to each
83device in the list.
84All the list entries created by this
85function must have their reference counter
86decremented when you are done with them,
87and the list itself must be freed.
88This
89function returns the number of devices in the list or a LIBUSB_ERROR code.
90.Pp
91.Ft void
92.Fn libusb_free_device_list "libusb_device **list" "int unref_devices"
93Free the list of devices discovered by libusb_get_device_list.
94If
95.Fa unref_device
96is set to 1 all devices in the list have their reference
97counter decremented once.
98.Pp
99.Ft uint8_t
100.Fn libusb_get_bus_number "libusb_device *dev"
101Returns the number of the bus contained by the device
aa3e5c14 102.Fa dev .
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104.Ft int
105.Fn libusb_get_port_numbers "libusb_device *dev" "uint8_t *buf" "uint8_t bufsize"
106Stores, in the buffer
107.Fa buf
108of size
109.Fa bufsize ,
110the list of all port numbers from root for the device
111.Fa dev .
112.Pp
113.Ft int
114.Fn libusb_get_port_path "libusb_context *ctx" "libusb_device *dev" "uint8_t *buf" "uint8_t bufsize"
115Deprecated function equivalent to libusb_get_port_numbers.
116.Pp
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117.Ft uint8_t
118.Fn libusb_get_device_address "libusb_device *dev"
119Returns the device_address contained by the device
aa3e5c14 120.Fa dev .
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121.Pp
122.Ft enum libusb_speed
123.Fn libusb_get_device_speed "libusb_device *dev"
124Returns the wire speed at which the device is connected.
125See the LIBUSB_SPEED_XXX enums for more information.
126LIBUSB_SPEED_UNKNOWN is returned in case of unknown wire speed.
127.Pp
128.Ft int
129.Fn libusb_get_max_packet_size "libusb_device *dev" "unsigned char endpoint"
130Returns the wMaxPacketSize value on success, LIBUSB_ERROR_NOT_FOUND if the
131endpoint does not exist and LIBUSB_ERROR_OTHERS on other failure.
132.Pp
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133.Ft int
134.Fn libusb_get_max_iso_packet_size "libusb_device *dev" "unsigned char endpoint"
135Returns the packet size multiplied by the packet multiplier on success,
136LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist and
137LIBUSB_ERROR_OTHERS on other failure.
138.Pp
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139.Ft libusb_device *
140.Fn libusb_ref_device "libusb_device *dev"
141Increment the reference counter of the device
aa3e5c14 142.Fa dev .
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143.Pp
144.Ft void
145.Fn libusb_unref_device "libusb_device *dev"
146Decrement the reference counter of the device
aa3e5c14 147.Fa dev .
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148.Pp
149.Ft int
150.Fn libusb_open "libusb_device *dev" "libusb_device_handle **devh"
151Open a device and obtain a device_handle.
152Returns 0 on success,
153LIBUSB_ERROR_NO_MEM on memory allocation problems, LIBUSB_ERROR_ACCESS
154on permissions problems, LIBUSB_ERROR_NO_DEVICE if the device has been
155disconnected and a LIBUSB_ERROR code on other errors.
156.Pp
157.Ft libusb_device_handle *
158.Fn libusb_open_device_with_vid_pid "libusb_context *ctx" "uint16_t vid" "uint16_t pid"
159A convenience function to open a device by vendor and product IDs
160.Fa vid
161and
aa3e5c14 162.Fa pid .
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163Returns NULL on error.
164.Pp
165.Ft void
166.Fn libusb_close "libusb_device_handle *devh"
167Close a device handle.
168.Pp
169.Ft libusb_device *
170.Fn libusb_get_device "libusb_device_handle *devh"
171Get the device contained by devh.
172Returns NULL on error.
173.Pp
174.Ft int
175.Fn libusb_get_configuration "libusb_device_handle *devh" "int *config"
aa3e5c14 176Returns the value of the current configuration.
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177Returns 0
178on success, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
179and a LIBUSB_ERROR code on error.
180.Pp
181.Ft int
182.Fn libusb_set_configuration "libusb_device_handle *devh" "int config"
183Set the active configuration to
184.Fa config
185for the device contained by
aa3e5c14 186.Fa devh .
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187This function returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the requested
188configuration does not exist, LIBUSB_ERROR_BUSY if the interfaces are currently
189claimed, LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and a
190LIBUSB_ERROR code on failure.
191.Pp
192.Ft int
193.Fn libusb_claim_interface "libusb_device_handle *devh" "int interface_number"
194Claim an interface in a given libusb_handle
aa3e5c14 195.Fa devh .
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196This is a non-blocking function.
197It returns 0 on success, LIBUSB_ERROR_NOT_FOUND
198if the requested interface does not exist, LIBUSB_ERROR_BUSY if a program or
199driver has claimed the interface, LIBUSB_ERROR_NO_DEVICE if the device has
200been disconnected and a LIBUSB_ERROR code on failure.
201.Pp
202.Ft int
203.Fn libusb_release_interface "libusb_device_handle *devh" "int interface_number"
204This function releases an interface.
205All the claimed interfaces on a device must be released
206before closing the device.
207Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the
208interface was not claimed, LIBUSB_ERROR_NO_DEVICE if the device has been
209disconnected and LIBUSB_ERROR on failure.
210.Pp
211.Ft int
212.Fn libusb_set_interface_alt_setting "libusb_device_handle *dev" "int interface_number" "int alternate_setting"
213Activate an alternate setting for an interface.
214Returns 0 on success,
215LIBUSB_ERROR_NOT_FOUND if the interface was not claimed or the requested
216setting does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been
217disconnected and a LIBUSB_ERROR code on failure.
218.Pp
219.Ft int
220.Fn libusb_clear_halt "libusb_device_handle *devh" "unsigned char endpoint"
221Clear an halt/stall for a endpoint.
222Returns 0 on success, LIBUSB_ERROR_NOT_FOUND
223if the endpoint does not exist, LIBUSB_ERROR_NO_DEVICE if the device has been
224disconnected and a LIBUSB_ERROR code on failure.
225.Pp
226.Ft int
227.Fn libusb_reset_device "libusb_device_handle *devh"
228Perform an USB port reset for an usb device.
229Returns 0 on success,
230LIBUSB_ERROR_NOT_FOUND if re-enumeration is required or if the device has
231been disconnected and a LIBUSB_ERROR code on failure.
232.Pp
233.Ft int
234.Fn libusb_check_connected "libusb_device_handle *devh"
235Test if the USB device is still connected.
236Returns 0 on success,
237LIBUSB_ERROR_NO_DEVICE if it has been disconnected and a LIBUSB_ERROR
238code on failure.
239.Pp
240.Ft int
241.Fn libusb_kernel_driver_active "libusb_device_handle *devh" "int interface"
242Determine if a driver is active on a interface.
243Returns 0 if no kernel driver is active
244and 1 if a kernel driver is active, LIBUSB_ERROR_NO_DEVICE
245if the device has been disconnected and a LIBUSB_ERROR code on failure.
246.Pp
247.Ft int
248.Fn libusb_get_driver "libusb_device_handle *devh" "int interface" "char *name" "int namelen"
249or
250.Ft int
251.Fn libusb_get_driver_np "libusb_device_handle *devh" "int interface" "char *name" "int namelen"
252Copy the name of the driver attached to the given
253.Fa device
254and
255.Fa interface
256into the buffer
257.Fa name
258of length
259.Fa namelen .
260Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if no kernel driver is attached
261to the given interface and LIBUSB_ERROR_INVALID_PARAM if the interface does
262not exist.
263This function is non-portable.
264The buffer pointed to by
265.Fa name
266is only zero terminated on success.
267.Pp
268.Ft int
269.Fn libusb_detach_kernel_driver "libusb_device_handle *devh" "int interface"
270or
271.Ft int
272.Fn libusb_detach_kernel_driver_np "libusb_device_handle *devh" "int interface"
273Detach a kernel driver from an interface.
274This is needed to claim an interface already claimed by a kernel driver.
275Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if no kernel driver was active,
276LIBUSB_ERROR_INVALID_PARAM if the interface does not exist,
277LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
278and a LIBUSB_ERROR code on failure.
279This function is non-portable.
280.Pp
281.Ft int
282.Fn libusb_attach_kernel_driver "libusb_device_handle *devh" "int interface"
283Re-attach an interface kernel driver that was previously detached.
284Returns 0 on success,
285LIBUSB_ERROR_INVALID_PARAM if the interface does not exist,
286LIBUSB_ERROR_NO_DEVICE
287if the device has been disconnected, LIBUSB_ERROR_BUSY if the driver cannot be
288attached because the interface is claimed by a program or driver and a
289LIBUSB_ERROR code on failure.
1d96047e 290.Sh USB DESCRIPTORS
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291.Ft int
292.Fn libusb_get_device_descriptor "libusb_device *dev" "libusb_device_descriptor *desc"
293Get the USB device descriptor for the device
aa3e5c14 294.Fa dev .
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295This is a non-blocking function.
296Returns 0 on success and a LIBUSB_ERROR code on
297failure.
298.Pp
299.Ft int
aa3e5c14 300.Fn libusb_get_active_config_descriptor "libusb_device *dev" "struct libusb_config_descriptor **config"
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301Get the USB configuration descriptor for the active configuration.
302Returns 0 on
303success, LIBUSB_ERROR_NOT_FOUND if the device is in
304an unconfigured state
305and a LIBUSB_ERROR code on error.
306.Pp
307.Ft int
308.Fn libusb_get_config_descriptor "libusb_device *dev" "uint8_t config_index" "libusb_config_descriptor **config"
309Get a USB configuration descriptor based on its index
222217a1 310.Fa idx .
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311Returns 0 on success, LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
312and a LIBUSB_ERROR code on error.
313.Pp
314.Ft int
315.Fn libusb_get_config_descriptor_by_value "libusb_device *dev" "uint8 bConfigurationValue" "libusb_config_descriptor **config"
316Get a USB configuration descriptor with a specific bConfigurationValue.
317This is
318a non-blocking function which does not send a request through the device.
319Returns 0
320on success, LIBUSB_ERROR_NOT_FOUND if the configuration
321does not exist and a
322LIBUSB_ERROR code on failure.
323.Pp
324.Ft void
325.Fn libusb_free_config_descriptor "libusb_config_descriptor *config"
326Free a configuration descriptor.
327.Pp
328.Ft int
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329.Fn libusb_get_string_descriptor "libusb_device_handle *devh" "uint8_t desc_idx" "uint16_t langid" "unsigned char *data" "int length"
330Retrieve a string descriptor in raw format.
331Returns the number of bytes actually transferred on success
332or a negative LIBUSB_ERROR code on failure.
333.Pp
334.Ft int
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335.Fn libusb_get_string_descriptor_ascii "libusb_device_handle *devh" "uint8_t desc_idx" "unsigned char *data" "int length"
336Retrieve a string descriptor in C style ASCII.
337Returns the positive number of bytes in the resulting ASCII string
338on success and a LIBUSB_ERROR code on failure.
339.Pp
340.Ft int
341.Fn libusb_parse_ss_endpoint_comp "const void *buf" "int len" "libusb_ss_endpoint_companion_descriptor **ep_comp"
342This function parses the USB 3.0 endpoint companion descriptor in host endian format pointed to by
343.Fa buf
344and having a length of
aa3e5c14 345.Fa len .
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346Typically these arguments are the extra and extra_length fields of the
347endpoint descriptor.
348On success the pointer to resulting descriptor is stored at the location given by
aa3e5c14 349.Fa ep_comp .
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350Returns zero on success and a LIBUSB_ERROR code on failure.
351On success the parsed USB 3.0 endpoint companion descriptor must be
352freed using the libusb_free_ss_endpoint_comp function.
353.Pp
354.Ft void
355.Fn libusb_free_ss_endpoint_comp "libusb_ss_endpoint_companion_descriptor *ep_comp"
356This function is NULL safe and frees a parsed USB 3.0 endpoint companion descriptor.
357.Pp
358.Ft int
359.Fn libusb_parse_bos_descriptor "const void *buf" "int len" "libusb_bos_descriptor **bos"
360This function parses a Binary Object Store, BOS, descriptor into host endian format pointed to by
361.Fa buf
362and having a length of
aa3e5c14 363.Fa len .
1d96047e 364On success the pointer to resulting descriptor is stored at the location given by
aa3e5c14 365.Fa bos .
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366Returns zero on success and a LIBUSB_ERROR code on failure.
367On success the parsed BOS descriptor must be freed using the
368libusb_free_bos_descriptor function.
369.Pp
370.Ft void
371.Fn libusb_free_bos_descriptor "libusb_bos_descriptor *bos"
372This function is NULL safe and frees a parsed BOS descriptor.
1d96047e 373.Sh USB ASYNCHRONOUS I/O
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374.Ft struct libusb_transfer *
375.Fn libusb_alloc_transfer "int iso_packets"
376Allocate a transfer with the number of isochronous packet descriptors
377specified by
378.Fa iso_packets .
379Returns NULL on error.
380.Pp
381.Ft void
382.Fn libusb_free_transfer "struct libusb_transfer *tr"
383Free a transfer.
384.Pp
385.Ft int
386.Fn libusb_submit_transfer "struct libusb_transfer *tr"
387This function will submit a transfer and returns immediately.
388Returns 0 on success, LIBUSB_ERROR_NO_DEVICE if
389the device has been disconnected and a
390LIBUSB_ERROR code on other failure.
391.Pp
392.Ft int
393.Fn libusb_cancel_transfer "struct libusb_transfer *tr"
394This function asynchronously cancels a transfer.
395Returns 0 on success and a LIBUSB_ERROR code on failure.
1d96047e 396.Sh USB SYNCHRONOUS I/O
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397.Ft int
398.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"
399Perform a USB control transfer.
400Returns the actual number of bytes
401transferred on success, in the range from and including zero up to and
402including
403.Fa wLength .
404On error a LIBUSB_ERROR code is returned, for example
405LIBUSB_ERROR_TIMEOUT if the transfer timed out, LIBUSB_ERROR_PIPE if the
406control request was not supported, LIBUSB_ERROR_NO_DEVICE if the
407device has been disconnected and another LIBUSB_ERROR code on other failures.
408The LIBUSB_ERROR codes are all negative.
409.Pp
410.Ft int
411.Fn libusb_bulk_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout"
412Perform an USB bulk transfer.
413A timeout value of zero means no timeout.
414The timeout value is given in milliseconds.
415Returns 0 on success, LIBUSB_ERROR_TIMEOUT
416if the transfer timed out, LIBUSB_ERROR_PIPE if the control request was not
417supported, LIBUSB_ERROR_OVERFLOW if the device offered more data,
418LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and
419a LIBUSB_ERROR code on other failure.
420.Pp
421.Ft int
422.Fn libusb_interrupt_transfer "struct libusb_device_handle *devh" "unsigned char endpoint" "unsigned char *data" "int length" "int *transferred" "unsigned int timeout"
423Perform an USB Interrupt transfer.
424A timeout value of zero means no timeout.
425The timeout value is given in milliseconds.
426Returns 0 on success, LIBUSB_ERROR_TIMEOUT
427if the transfer timed out, LIBUSB_ERROR_PIPE if the control request was not
428supported, LIBUSB_ERROR_OVERFLOW if the device offered more data,
429LIBUSB_ERROR_NO_DEVICE if the device has been disconnected and
430a LIBUSB_ERROR code on other failure.
1d96047e 431.Sh USB EVENTS
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432.Ft int
433.Fn libusb_try_lock_events "libusb_context *ctx"
434Try to acquire the event handling lock.
435Returns 0 if the lock was obtained and 1 if not.
436.Pp
437.Ft void
438.Fn libusb_lock_events "libusb_context *ctx"
439Acquire the event handling lock.
440This function is blocking.
441.Pp
442.Ft void
443.Fn libusb_unlock_events "libusb_context *ctx"
444Release the event handling lock.
445This will wake up any thread blocked
446on
aa3e5c14 447.Fn libusb_wait_for_event .
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448.Pp
449.Ft int
450.Fn libusb_event_handling_ok "libusb_context *ctx"
451Determine if it still OK for this thread to be doing event handling.
452Returns 1
453if event handling can start or continue.
454Returns 0 if this thread must give up
455the events lock.
456.Pp
457.Ft int
458.Fn libusb_event_handler_active "libusb_context *ctx"
459Determine if an active thread is handling events.
460Returns 1 if there is a thread handling events and 0 if there
461are no threads currently handling events.
462.Pp
463.Ft void
464.Fn libusb_lock_event_waiters "libusb_context *ctx"
465Acquire the event_waiters lock.
466This lock is designed to be obtained in the
467situation where you want to be aware when events are completed, but some other
468thread is event handling so calling libusb_handle_events() is not allowed.
469.Pp
470.Ft void
471.Fn libusb_unlock_event_waiters "libusb_context *ctx"
472Release the event_waiters lock.
473.Pp
474.Ft int
475.Fn libusb_wait_for_event "libusb_context *ctx" "struct timeval *tv"
476Wait for another thread to signal completion of an event.
477Must be called
478with the event waiters lock held, see libusb_lock_event_waiters().
479This will
480block until the timeout expires or a transfer completes or a thread releases
481the event handling lock through libusb_unlock_events().
482Returns 0 after a
483transfer completes or another thread stops event handling, and 1 if the
484timeout expired.
485.Pp
486.Ft int
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487.Fn libusb_handle_events_timeout_completed "libusb_context *ctx" "struct timeval *tv" "int *completed"
488Handle any pending events by checking if timeouts have expired and by
489checking the set of file descriptors for activity.
490If the
491.Fa completed
492argument is not equal to NULL, this function will
493loop until a transfer completion callback sets the variable pointed to
494by the
495.Fa completed
496argument to non-zero.
497If the
498.Fa tv
499argument is not equal to NULL, this function will return
500LIBUSB_ERROR_TIMEOUT after the given timeout.
501Returns 0 on success, or a LIBUSB_ERROR code on failure or timeout.
502.Pp
503.Ft int
504.Fn libusb_handle_events_completed "libusb_context *ctx" "int *completed"
505Handle any pending events by checking the set of file descriptors for activity.
506If the
507.Fa completed
508argument is not equal to NULL, this function will
509loop until a transfer completion callback sets the variable pointed to
510by the
511.Fa completed
512argument to non-zero.
513Returns 0 on success, or a LIBUSB_ERROR code on failure.
514.Pp
515.Ft int
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516.Fn libusb_handle_events_timeout "libusb_context *ctx" "struct timeval *tv"
517Handle any pending events by checking if timeouts have expired and by
518checking the set of file descriptors for activity.
519Returns 0 on success, or a
9b0c1abe 520LIBUSB_ERROR code on failure or timeout.
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521.Pp
522.Ft int
523.Fn libusb_handle_events "libusb_context *ctx"
524Handle any pending events in blocking mode with a sensible timeout.
525Returns 0
526on success and a LIBUSB_ERROR code on failure.
527.Pp
528.Ft int
529.Fn libusb_handle_events_locked "libusb_context *ctx" "struct timeval *tv"
aa3e5c14 530Handle any pending events by polling file descriptors, without checking if
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531another thread is already doing so.
532Must be called with the event lock held.
533.Pp
534.Ft int
535.Fn libusb_get_next_timeout "libusb_context *ctx" "struct timeval *tv"
536Determine the next internal timeout that libusb needs to handle.
537Returns 0
538if there are no pending timeouts, 1 if a timeout was returned, or a LIBUSB_ERROR
9b0c1abe 539code on failure or timeout.
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540.Pp
541.Ft void
542.Fn libusb_set_pollfd_notifiers "libusb_context *ctx" "libusb_pollfd_added_cb added_cb" "libusb_pollfd_removed_cb remove_cb" "void *user_data"
543Register notification functions for file descriptor additions/removals.
544These functions will be invoked for every new or removed file descriptor
545that libusb uses as an event source.
546.Pp
547.Ft const struct libusb_pollfd **
548.Fn libusb_get_pollfds "libusb_context *ctx"
34bf0d2d 549Retrieve a list of file descriptors that should be polled by your main loop as
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550libusb event sources.
551Returns a NULL-terminated list on success or NULL on failure.
552.Sh LIBUSB VERSION 0.1 COMPATIBILITY
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553The library is also compliant with LibUSB version 0.1.12.
554.Pp
555.Fn usb_open
556.Fn usb_close
557.Fn usb_get_string
558.Fn usb_get_string_simple
559.Fn usb_get_descriptor_by_endpoint
560.Fn usb_get_descriptor
561.Fn usb_parse_descriptor
562.Fn usb_parse_configuration
563.Fn usb_destroy_configuration
564.Fn usb_fetch_and_parse_descriptors
565.Fn usb_bulk_write
566.Fn usb_bulk_read
567.Fn usb_interrupt_write
568.Fn usb_interrupt_read
569.Fn usb_control_msg
570.Fn usb_set_configuration
571.Fn usb_claim_interface
572.Fn usb_release_interface
573.Fn usb_set_altinterface
574.Fn usb_resetep
575.Fn usb_clear_halt
576.Fn usb_reset
577.Fn usb_strerror
578.Fn usb_init
579.Fn usb_set_debug
580.Fn usb_find_busses
581.Fn usb_find_devices
582.Fn usb_device
583.Fn usb_get_busses
584.Fn usb_check_connected
585.Fn usb_get_driver_np
586.Fn usb_detach_kernel_driver_np
587.Sh SEE ALSO
588.Xr libusb20 3 ,
589.Xr usb 4 ,
590.Xr usbconfig 8 ,
591.Xr usbdump 8
592.Pp
593.Pa http://libusb.sourceforge.net/
594.Sh HISTORY
595.Nm
596support first appeared in
597.Fx 8.0 .