KFIFO_LEN(9) FIFO Buffer KFIFO_LEN(9)NAME
kfifo_len - returns the number of used elements in the fifo
address of the fifo to be used
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 KFIFO_LEN(9)
Check Out this Related Man Page
fifo - Create and manipulate u-turn fifo channels
package require Tcl
package require memchan
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 accomodate 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 transfered 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
The value of this option is the number of bytes currently stored in the queried memory channel.
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-
The channels are also readable if they contain more than zero bytes. Under this conditions a readable fileevent-handler will fire continu-
One possible application of memory channels created by memchan or fifo is as temporay 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.
fifo2, memchan, null
channel, fifo, i/o, in-memory channel, memchan, stream
Copyright (c) 1996-2003 Andreas Kupries <email@example.com>
Memory channels 2.1 fifo(n)
I know the following questions are noobish questions but I am asking them because I am confused about the basics of history behind UNIX and LINUX.
Ok onto business, my questions are-:
Was/Is UNIX ever an open source operating system ?
If UNIX was... (21 Replies)
Hello and thanks in advance for any help anyone can offer me
I'm trying to learn the find command and thought I was understanding it... Apparently I was wrong. I was doing compound searches and I started getting weird results with the -size test. I was trying to do a search on a 1G file owned by... (14 Replies)
i have installed quota on my centos 7 machine and its what im after (setting size limit on users, so they cant fill the hard drive)
i want to now make this part of my create user script for my sftp server so i want to do a echo and a read command so i capture the limit they enter... (0 Replies)
I need to write a shell script which opens a file and increments the version(text) within the file every time the script runs. For example:
$ cat docker_file.yml
So, I would like... (6 Replies)
We use DB2 v10.5 and using DBArtisan tool
Can someone please guide how to convert digits to binary numbers using db2 feature.
Ex> for number 9 , binary should be 1001 ( 8+1)
Any help appreciated. Thanks (2 Replies)
how to using tar with exclude directory and compress it using tar.Z
i only know how to exclude dir only with this command below:
tar -cvf /varios/restore/test.tar -X excludefile.txt /jfma/test1/
how to compress it using 1 command?
Please use CODE tags as... (6 Replies)
Quite an obscure question I think.
We have a rebuild process for remote sites that allows us to PXE rebuild a till (actually a PC with a touch screen and various fancy bits) running CentOS. The current CentOS5 tills work just fine with a tar image restore and some personalisation. Sadly,... (4 Replies)
I had recently learnt a bit of Docker(which provides containerization process).
Here are some of my learning points from it.
Let us start first with very basic question:
What is Docker:
Docker is a platform for sysadmins and developers to DEPLOY, DEVELOP and RUN applications ... (7 Replies)
What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend (3 Replies)
Hello... And thanks in advance for any help anyone can offer me
I was trying to work out the differences between displaying modify, access, and change times with the 'ls' command. Everything seems in order when I look at files, but the access time on a directory doesn't seem to change when I... (4 Replies)
I am having an issue here with CentOS release 6.6 (Final) that shows all of the space used up, but I can't tell where the space went.
Seemingly I am using up 100%, according to
Filesystem Size Used Avail Use% Mounted on... (27 Replies)
I'm trying to use a bash script for a psych experiment that involves listening to sound files and responding. If I have something like the code below, how can I make sure that a key press is assigned to RESPONSE only after the second echo statement?
for i in 1 2 3; do
... (10 Replies)
After the success of the jq - tool for parsing and manipulating JSON-Data someone wrote a tool called yq, which aims to be the same for YAML, what jq is for JSON. Seems to work fine. I'll definitely give it a chance in future.
... (1 Reply)
I am very pleased to announce that Dave Munro (gull04) is joining the Moderation Team, after being a very valuable member of UNIX.com for 15+ years.
Dave is an IT Consultant with 30 years of experience this year, has worked in many of the industry vertical market segments and has... (6 Replies)