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