Sponsored Content
Full Discussion: Which is more expensive ?
Top Forums Programming Which is more expensive ? Post 302131738 by reborg on Monday 13th of August 2007 12:35:54 PM
Old 08-13-2007
I don't think there would be any real difference here, there might me a very marginal improvement in the second case due to the number of comparison you are doing, but would expect that to be marginal. You are after all incrementing the same number of times in both cases anc calling close() the same number of time.

Just curious, is this shutdown code or is it after forking that you are closing the open fds?
 

2 More Discussions You Might Find Interesting

1. Programming

calling pthread_self (on ubuntu), expensive?

Hi all, Is anyone aware of what operations are involved when a call to pthread_self() is made, obtaining the unique thread ID on a Ubuntu system (or even any Linux flavour)? Specifically, to retrieve the thread id, is there any locking required or atomic operations? I'm building an... (11 Replies)
Discussion started by: gorga
11 Replies

2. What is on Your Mind?

Very Expensive Running Shoes

You really should not need one third of the entire US budget to buy a pair of running shoes... even if they are name brand. What have these guys been smoking? It reminds me of the old joke... Customer: At those prices you aren't going to sell many shoes. Salesman: Ah, but all we need to do is... (4 Replies)
Discussion started by: Perderabo
4 Replies
SHUTDOWN(8)						      System Manager's Manual						       SHUTDOWN(8)

NAME
shutdown - graciously close the system down SYNOPSIS
shutdown [-hrRmk] [-x code] [time-specification [message]] DESCRIPTION
Shutdown is a program which allows a system operator to close down the system in an nice way. Shutdown informs the users why and when the system is going down. This warning is issued 10 minutes before shutdown time and every minute in the last 5 minutes. At this time (5 min- utes), shutdown creates a file /etc/nologin to prevent new users from logging in. Shutdown keeps a logfile of shutdowns. Every shutdown is registered in /usr/adm/wtmp, if this file exists. After these actions, a call is done to reboot(2) which actually brings the system down. Time-specification may be something like 15:00, 15.00, +15, or now for a shutdown at 3pm (twice), 15 minutes from now, or immediately. The message may be used to describe why the system is going down, it may also be typed on standard input with the -m option. OPTIONS
-h This flag prevents the system from rebooting after the shutdown. The system can now be powered off. This is the default. -r This flag indicates that the system should reboot after shutting down. -R Reboot the system by resetting it. Normally the kernel will try to return to the Boot Monitor. With -R the system will receive a hardware reset. -x code Halt the system and let the Monitor execute the given code as if typed at the monitor prompt. You can for instance use -x 'boot hd0' as a very fast way to reboot "from the top." -m Allows the operator to type a shutdown message on standard input, that will be added to the messages displayed on all terminals. -k This option gives the possibility of terminating an already started shutdown. This is only possible if shutdown time has not yet arrived. -C Check if the system crashed. This option is not used at shutdown time, but at reboot time. It tells if the file systems should be checked by testing if the last entry in the wtmp file is a shutdown entry. (A crude replacement for a file system clean flag.) FILES
/usr/adm/wtmp, /etc/nologin, /usr/adm/authlog SEE ALSO
reboot(2), wall(1), halt(8), boot(8). AUTHOR
Edvard Tuinder (v892231@si.hhs.NL) SHUTDOWN(8)
All times are GMT -4. The time now is 01:06 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy