ndelay_off(3) Library Functions Manual ndelay_off(3)NAME
ndelay_off - put file descriptor in non-blocking mode
SYNTAX
#include <ndelay.h>
extern int ndelay_off(int fd);
DESCRIPTION
ndelay_off puts a file descriptor in blocking mode. Reading from and writing to blocking network sockets, FIFOs or device files will pos-
sibly not return immediately but wait on more input or buffer space for output.
If an error occurred, ndelay_off will return nonzero and set errno accordingly.
SEE ALSO fcntl(2), ndelay_on(3)ndelay_off(3)
Check Out this Related Man Page
io_nonblock(3) Library Functions Manual io_nonblock(3)NAME
io_nonblock - switch to non-blocking I/O
SYNTAX
#include <io.h>
void io_nonblock(int64 fd);
DESCRIPTION
io_nonblock puts UNIX descriptor fd into ``non-blocking mode.'' Calling io_nonblock(fd) before io_fd(fd) makes io_tryread and io_trywrite
faster and more efficient.
Actually, current UNIX kernels do not support non-blocking descriptors; they support non-blocking open files. Furthermore, many programs
will break if they encounter non-blocking mode. This means that you must not use io_nonblock for a descriptor inherited from another pro-
gram.
io_nonblock has no return value; it always succeeds. If d is not the number of a UNIX descriptor, io_nonblock has no effect.
If io_fd is given a descriptor in blocking mode, io_tryread and io_trywrite go through the following contortions to avoid blocking:
1 Stop if poll says that the descriptor is not ready. Otherwise there's a good chance, but not a guarantee: even if poll says the descrip-
tor is ready, the descriptor might not be ready a moment later. (Furthermore, poll can fail on some systems.)
2 Catch SIGALRM. SIGALRM must not be blocked, and must not be used elsewhere in the program.
3 Set an interval timer so that any blocking call will be interrupted by SIGALRM within 10 milliseconds. (Current UNIX kernels do not
allow any shorter interval.) Of course, this may still mean a 10-millisecond delay.
If io_fd is given a descriptor in non-blocking mode (or a descriptor for a regular disk file), io_tryread and io_trywrite avoid these con-
tortions.
SEE ALSO io_wait(3), io_canwrite(3)io_nonblock(3)
I have a huge matrix file containing some 1.5 million rows and 6000 columns. The matrix looks something like this:
1 2 3
4 5 6
7 8 9
3 4 5
I want to add all the numbers in the columns of this matrix and display the result to my stdout. This means that the numbers in the first column are:
... (2 Replies)
Hi,
Just trying to get to grips with sed and awk for some reporting for work and I need some assistance:
I have a file that lists policy names on the first line and then on the second line whether the policy is active or not.
Policy Name: Policy1
Active: yes
Policy... (8 Replies)
version info :
vi availabe with RHEL 5.4
I have a text file with 10,000 lines. I want to copy lines from 5000th line to 7000th and redirect to a file. Any idea how I can do this?
Note:
The above scenario is just an example. In my actual requirement, the file has 14 million lines and I want... (9 Replies)
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)
Hello,
I couldn't find an actual introduction thread, so I decided to just put this here.
I go by d0wngrade online. I have been programming in multiple languages for about 15+ years. I started with standard web design languages like HTML and CSS, but I then advanced from design to development... (2 Replies)
Hi guys...
The first active code line in AudioScope.sh is set -u .
This causes a complete exit if a variable is used/found but has not been allocated at the start of the program.
However, apart from writing code to do the task, is there a switch to to check which variables have been... (17 Replies)
Hi.
In thread https://www.unix.com/shell-programming-and-scripting/267833-grouping-counting.html rovf and I had a mini-discussion on grep and awk.
Here is a demo script that compares the awk and grep approaches for this single problem:
#!/usr/bin/env bash
# @(#) s2 Demonstrate group... (1 Reply)
Hello,
I have to fish out some specific columns from a file based on the header value. I have the list of columns I need in a different file. I thought I could read in the list of headers I need,
# file with header names of required columns in required order
headers_file=$2
# read contents... (11 Replies)
For those interested in installing dash shell on OSX Lion to help test POSIX compliancy of shell scripts, it is quite easy. I did it like this:
If you don't have gcc on your system:
0. Download and install the Command Line Tools for Xcode package from Sign In - Apple *
1. Download the dash... (2 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 data of an excel files as given below,
file1
org1_1 1 1 2.5 100
org1_2 1 2 5.5 98
org1_3 1 3 7.2 88
file2
org2_1 1 1 2.5 100
org2_2 1 2 5.5 56
org2_3 1 3 7.2 70
I have multiple excel files as above shown.
I have to copy column 1, column 4 and paste into a new excel file as... (26 Replies)
Dear All,
Taking a break from Vue.js coding for the site, SEO and YT videos; and hopefully addressing some well deserved criticism from some here that I have been too focused on the visual aspects of the forums versus the substance and the community....
While the "current generation... (9 Replies)
Hi all...
Well guys and gals, I jumped in at the deep end and found things that PERL cannot do by default.
Many tricky terminal escape codes are not catered for so I had to create workarounds.
One thing I searched for was this:
Passing perl variable to shell command
AND, @Neo this was... (15 Replies)