Lines Matching +full:read +full:- +full:to +full:- +full:read

1 .. SPDX-License-Identifier: GPL-2.0
12 GPIO_V2_LINEINFO_CHANGED_READ - Read line info changed events for watched
18 ``int read(int chip_fd, void *buf, size_t count)``
27     The buffer to contain the :c:type:`events<gpio_v2_line_info_changed>`.
36 Read line info changed events for watched lines from the chip.
42     These events relate to changes in a line's request state or configuration,
43     not its value. Use gpio-v2-line-event-read.rst to receive events when a
46 A line must be watched using gpio-v2-get-lineinfo-watch-ioctl.rst to generate
51 from where they can be read by userspace at its convenience using `read()`.
55 The buffer may overflow if bursts of events occur quicker than they are read
59 Events read from the buffer are always in the same order that they were
63 To minimize the number of calls required to copy events from the kernel to
64 userspace, `read()` supports copying multiple events. The number of events
68 A `read()` will block if no event is available and the ``chip_fd`` has not
77 On success the number of bytes read, which will be a multiple of the size
80 On error -1 and the ``errno`` variable is set appropriately.
81 Common error codes are described in error-codes.rst.