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kfifo_to_user(9) [centos man page]

KFIFO_TO_USER(9)						    FIFO Buffer 						  KFIFO_TO_USER(9)

NAME
kfifo_to_user - copies data from the fifo into user space SYNOPSIS
kfifo_to_user(fifo, to, len, copied); ARGUMENTS
fifo address of the fifo to be used to where the data must be copied len the size of the destination buffer copied pointer to output variable to store the number of copied bytes DESCRIPTION
This macro copies at most len bytes from the fifo into the to buffer and returns -EFAULT/0. Note that with only one concurrent reader and one concurrent writer, you don't need extra locking to use these macro. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 KFIFO_TO_USER(9)

Check Out this Related Man Page

fifo(3tcl)                                                                                                                              fifo(3tcl)

NAME
fifo - Create and manipulate u-turn fifo channels SYNOPSIS
package require Tcl package require memchan fifo DESCRIPTION
fifo creates a stream-oriented in-memory channel and returns its handle. There is no restriction on the ultimate size of the channel, it will always grow as much as is necessary to accommodate the data written into it. In contrast to the channels generated by memchan a channel created here effectively represents an U-turn. All data written into it can be read out, but only in the same order. This also means that a fifo channel is not seekable. The channels created here can be transferred between interpreters in the same thread and between threads, but only as a whole. It is not possible to use them to create a bi- or unidirectional connection between two interpreters. Memory channels created by fifo provide two read-only options which can be queried via the standard fconfigure command. These are -length The value of this option is the number of bytes currently stored in the queried memory channel. -allocated The value of this option is the number of bytes currently allocated by the queried memory channel. This number is at least as big as the value of -length. As the channels generated by fifo grow as necessary they are always writable. This means that a writable fileevent-handler will fire con- tinuously. The channels are also readable if they contain more than zero bytes. Under this conditions a readable fileevent-handler will fire continu- ously. NOTES
One possible application of memory channels created by memchan or fifo is as temporary storage device to collect data coming in over a pipe or a socket. If part of the processing of the incoming data is to read and process header bytes or similar fifo are easier to use as they do not require seeking back and forth to switch between the assimilation of headers at the beginning and writing new data at the end. SEE ALSO
fifo2, memchan, null KEYWORDS
channel, fifo, i/o, in-memory channel, memchan, stream COPYRIGHT
Copyright (c) 1996-2003 Andreas Kupries <andreas_kupries@users.sourceforge.net> Memory channels 2.1 fifo(3tcl)
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