Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #150
Difficulty: Easy
Oracle discontinued OpenSolaris after their acquisition of Sun Microsystems.
True or False?
Linux & Unix Commands - Search Man Pages

wait_event_lock_irq_cmd(9) [centos man page]

WAIT_EVENT_LOCK_IRQ_(9) 					   Driver Basics					   WAIT_EVENT_LOCK_IRQ_(9)

NAME
wait_event_lock_irq_cmd - sleep until a condition gets true. The condition is checked under the lock. This is expected to be called with the lock taken. SYNOPSIS
wait_event_lock_irq_cmd(wq, condition, lock, cmd); ARGUMENTS
wq the waitqueue to wait on condition a C expression for the event to wait for lock a locked spinlock_t, which will be released before cmd and schedule and reacquired afterwards. cmd a command which is invoked outside the critical section before sleep DESCRIPTION
The process is put to sleep (TASK_UNINTERRUPTIBLE) until the condition evaluates to true. The condition is checked each time the waitqueue wq is woken up. wake_up has to be called after changing any variable that could change the result of the wait condition. This is supposed to be called while holding the lock. The lock is dropped before invoking the cmd and going to sleep and is reacquired afterwards. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 WAIT_EVENT_LOCK_IRQ_(9)

Check Out this Related Man Page

sem_wait(2)							System Calls Manual						       sem_wait(2)

NAME
sem_wait, sem_trywait - lock a POSIX semaphore SYNOPSIS
DESCRIPTION
is used to lock a semaphore. The calling thread will not return from its call to until one of the following events occur: it successfully obtains a lock on the semaphore; it is interrupted by a signal or an error condition occurs. is used to lock a semaphore, if it is available. The value of the semaphore sem is checked at some unspecified time during the call. If the semaphore is available at the time its value is checked, the calling thread will atomically, with respect to the checking of the value, lock the semaphore. The thread will now own a lock on the semaphore; the call will return successfully. If the semaphore is unavailable at the time its value is checked, then the call returns -1 with errno set to EAGAIN. If the specified semaphore referred to by sem is a named semaphore, then this semaphore must have been opened by the calling process with The calling process must have both read and write permissions on the semaphore to perform these operations. The semaphore will be locked upon successful return and will stay locked until it is explicitly released by a call to To use this function, link in the realtime library by specifying on the compiler or linker command line. EXAMPLES
The following call to will lock the semaphore sem. The following call to will lock the semaphore sem, if it is available. RETURN VALUE
A successful call to will return 0 and the calling thread will then own a lock on the semaphore. Otherwise, the call to will return -1 with errno set to the appropriate value of the error condition. A successful call to will return 0, if the semaphore was available and the calling thread was able to lock the semaphore. Otherwise, the call to will return -1 with errno set to the appropriate value of the error condition. ERRORS
and fail and do not perform the requested operation if any of the following conditions are encountered: [EPERM] The calling process does not have the privileges necessary to lock the semaphore. [EAGAIN] The semaphore was not available and hence could not be locked by This error condition only occurs in [EINVAL] The argument sem does not refer to a valid semaphore. [EINTR] The function was interrupted by a signal SEE ALSO
sem_post(2), <semaphore.h>. STANDARDS CONFORMANCE
sem_wait(2)

15 More Discussions You Might Find Interesting

1. Fedora

Is UNIX an open source OS ?

Hi everyone, 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)
Discussion started by: sreyan32
21 Replies

2. UNIX for Beginners Questions & Answers

Weird 'find' results

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)
Discussion started by: bodisha
14 Replies

3. UNIX for Beginners Questions & Answers

Set hard block limit for user using quota

hi all, 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)
Discussion started by: robertkwild
0 Replies

4. UNIX for Beginners Questions & Answers

Best performance UNIX just for HOST Virtualization?

Hi everybody, Which Unix base OS have best performance for HOST virtualization? I tested SmartOS but it needs another OS to connect remotely! Thanks in advance. (11 Replies)
Discussion started by: mbzadegan
11 Replies

5. UNIX for Beginners Questions & Answers

How to increment version inside a file?

Hi All, 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 version: '3.1' services: ui: image: repo-srv.dev.io:5000/facebook/ui:0.0.2-QA1 $ So, I would like... (6 Replies)
Discussion started by: akshayupadhayay
6 Replies

6. Programming

DB2 convert digits to binary format

Dear Team 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)
Discussion started by: Perlbaby
2 Replies

7. UNIX for Advanced & Expert Users

Tar Command

hi folks, 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? Thanx Please use CODE tags as... (6 Replies)
Discussion started by: only
6 Replies

8. UNIX for Advanced & Expert Users

CentOS7 restoring file capabilities

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)
Discussion started by: rbatte1
4 Replies

9. Docker

Docker learning Phase-I

Hello All, 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)
Discussion started by: RavinderSingh13
7 Replies

10. UNIX for Advanced & Expert Users

Shopt -s histappend

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)
Discussion started by: cokedude
3 Replies

11. UNIX for Beginners Questions & Answers

Unsure why access time on a directory change isn't changing

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)
Discussion started by: bodisha
4 Replies

12. UNIX for Beginners Questions & Answers

CentOS 6 ran out of space, need to reclaim it

Hello everyone, 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 df -h Filesystem Size Used Avail Use% Mounted on... (27 Replies)
Discussion started by: DannyBoyCentOS
27 Replies

13. Shell Programming and Scripting

Controlling user input

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 echo "Ready?" sleep 2 ... (10 Replies)
Discussion started by: darwin_886
10 Replies

14. Shell Programming and Scripting

[TIP] Processing YAML files with yq

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. Example YAML-File: --- !ruby/object:Puppet::Node::Facts ... (1 Reply)
Discussion started by: stomp
1 Replies

15. What is on Your Mind?

Please Welcome Dave Munro to the Moderator Team!

Dear All, 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)
Discussion started by: Neo
6 Replies

Featured Tech Videos