Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

_lwp_ctl(2) [netbsd man page]

_LWP_CTL(2)						      BSD System Calls Manual						       _LWP_CTL(2)

_lwp_ctl -- prepare per-LWP communication area between kernel and userland LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <lwp.h> int _lwp_ctl(int features, struct lwpctl **address); DESCRIPTION
_lwp_ctl() prepares per-LWP communication area for the calling LWP, and maps it into the calling process' address space. It takes the fol- lowing arguments. features The bitwise-OR of the following flags. LWPCTL_FEATURE_CURCPU Request lc_curcpu. LWPCTL_FEATURE_PCTR Request lc_pctr. address The address to store a pointer to lwpctl structure for the calling LWP. The per-LWP communication area is described by an lwpctl structure. It has following members, depending on features. int lc_curcpu The integral identifier of the CPU on which the LWP is running, or LWPCTL_CPU_NONE when the LWP is not running on any CPU. It's updated by the kernel and should be considered as read-only for userland. It's available only if requested with the LWPCTL_FEATURE_CURCPU flag. int lc_pctr The integer which is incremented on every context switches to the LWP. It can be used to detect preemption of the LWP. (thus its name "preemption counter".) It's updated by the kernel and should be considered as read-only for userland. It's avail- able only if requested with the LWPCTL_FEATURE_PCTR flag. RETURN VALUES
_lwp_ctl() returns 0 on success. Otherwise, -1 is returned and errno is set to indicate the error. SEE ALSO
errno(2) BSD
May 5, 2008 BSD

Check Out this Related Man Page

KPREEMPT(9)						   BSD Kernel Developer's Manual					       KPREEMPT(9)

kpreempt -- control kernel preemption SYNOPSIS
#include <sys/systm.h> void kpreempt_disable(void); void kpreempt_enable(void); bool kpreempt_disabled(void); DESCRIPTION
These functions are used to control kernel preemption of the calling LWP. On architectures where kernel preemption is not supported natively, these functions may still be used. It should be noted that kernel preemption is also disabled when holding the interrupt priority level above IPL_NONE, e.g. using spl(9) or spinning mutex(9) calls or holding kernel_lock (indicating that the code is not MT safe). kpreempt_disable() disables kernel preemption of the calling LWP. Note that disabling kernel preemption can prevent LWPs with higher priori- ties from running. kpreempt_enable() enables kernel preemption of the calling LWP, which was previously disabled by kpreempt_disable(). kpreempt_disable() and kpreempt_enable() can be nested. kpreempt_disabled() returns true if preemption of the calling LWP is disabled. It is only for diagnostic purpose. SEE ALSO
intro(9), mutex(9), spl(9) BSD
February 16, 2010 BSD
Man Page

13 More Discussions You Might Find Interesting

1. Tips and Tutorials

Unix File Permissions

Introduction I have seen some misinformation regarding Unix file permissions. I will try to set the record straight. Take a look at this example of some output from ls: $ ls -ld /usr/bin /usr/bin/cat drwxrwxr-x 3 root bin 8704 Sep 23 2004 /usr/bin -r-xr-xr-x 1 bin bin ... (6 Replies)
Discussion started by: Perderabo
6 Replies

2. Shell Programming and Scripting

sorting left-justified numeric values

I have a file which looks roughly like this: 996 mmmmmmm 996 xxxxxxxxxxxxx 99600 ssssssssss 9964 fffffffffffff and would like to sort it numerically on the first field. I tried: sort -nr --key=1 .... The output I get is: 99600 ssssssssss 9964 ... (3 Replies)
Discussion started by: rovf
3 Replies

3. Programming

Memory Leaks

Suppose I have a main() function with only one malloc statement allocating say some 1 gb memory. Also say my system has 1 gb of ram. main() { malloc(1gb) return(0) } The program above exits without freeing the memory. In this case will the 1 gb of heap memory be returned... (9 Replies)
Discussion started by: rupeshkp728
9 Replies

4. Solaris

How to install PGX32 on Sparc 10 Ultra?

I'm trying to install a PGX32 video card on my Sparc 10 Ultra running Solaris 10. I've got the Oracle installation guide for it and I got as far as: "4. Insert the CD-ROM labeled “GFX OpenWindows for Solaris 2” into the drive." I don't have a CD-ROM by that name and a web search for that... (21 Replies)
Discussion started by: Michele31416
21 Replies

5. Shell Programming and Scripting

Better to Use Return Code or wc -l Output?

Hey All, Quick question... I'm writing a short script to check if a continuous port is running on a server. I'm using "ps -ef | grep -v grep | grep processName" and I was wondering if it was better/more reliable to just check the return code from the command or if its better to pipe to... (12 Replies)
Discussion started by: mrm5102
12 Replies

6. Shell Programming and Scripting

Vm versus physical linux server

Does anyone have a script that can be run to tell you if you are on either a VM Linux or a physical Linux server? (15 Replies)
Discussion started by: bigbenn
15 Replies

7. BSD

NetBSD 6.1.2: apm and admd not found

I installed NetBSD 6.1.2 amd64 and can't find the apm utility. Is it not in the base system? Is it necessary to recompile the default amd64 kernel to use apm? Or is there a new method for power management and suspend/resume? (2 Replies)
Discussion started by: bsdx
2 Replies

8. Shell Programming and Scripting

RFC - Korn shell prompt

Hi, I am learning shell scripting for the first time. I use AT&T Korn Shell, Version AJM 93u+ 2012-08-01, compiled from source on NetBSD. So far I have managed to set up what I think is a useful and pleasing shell prompt, which can be seen in the image attached to this post. The prompt is... (2 Replies)
Discussion started by: gezley
2 Replies

9. Shell Programming and Scripting

Make bold chars in UNIX

Hi all, I want to make the string as bold in unix. is there any way to acheive this? thanks in advance. (16 Replies)
Discussion started by: SekhaReddy
16 Replies

10. Shell Programming and Scripting

Adding a List of Times

Hey gang, I have a list of times I need to sum up. This list can vary from a few to a few thousand entries. Now I had found a closed reference to adding time titled "add up time with xx:yy format in bash how?" In it, the example works great for that formatted list of times... This is the reply code... (5 Replies)
Discussion started by: Brusimm
5 Replies

11. UNIX for Beginners Questions & Answers

BSD Unix Toolbox: 1000+ Commands for FreeBSD, OpenBSD, and NetBSD

Usually when I on the evening go to bed I take some interesting book with me. I read it for a while to get me down to sleep. Probably most people seek information from the Nett by googleing but I am so oldfashioned I prefer a real book ;) But what a book. The one I found and ordered is BSD Unix®... (0 Replies)
Discussion started by: fossiili
0 Replies

12. UNIX for Beginners Questions & Answers

Grandpa returning to UNIX

On the late 1960s I got short hands on experience with a russian "small" computer. It vas a copy of DEC's VAX ... and running some version of BSD-Unix. After that I worked in a university following the development of computing. After retire I started collecting old pc's and installing... (13 Replies)
Discussion started by: fossiili
13 Replies

13. UNIX for Beginners Questions & Answers

Grep command to show the number of results

Hi I wanted to know if there is an option in grep command to show the number of results (not the number of lines of findings). Thanks (14 Replies)
Discussion started by: abdossamad2003
14 Replies