In one of my interview, interviewer asked the following question on deep copy constructor:
When we are externally overloading the copy constructor is there any optimization strategies when we are using several copy constructors.
My setup is Ubuntu 10.04, eclipse 3.5.2 I have created the source for a shared object and a test program to test it. The program executes dlopen() and I get back a valid library handle. I can use that handle and dlsym() to get the address of my C exported functions just as I expect. I recently added a change to have the so instantiate an object at load time by using a __attribute__ ((constructor)) function named so_init(). I also added a main() function (one wasn't required before). Adding a bunch of printf()s and using the debugger in eclipse I watch the code run and the so_init() and main() functions are never called. As far as I can tell, eclipse has -shared, -fPIC and -Wl setup and specified correctly. Am I missing a compile/link flag? Is there some magic I need in the so_main.cpp to get this working. I have this written as dual source code. The same code works quite nicely in Windows which calls dllMain() as expected.
View 4 Replies View RelatedIn my project,Login window is created as a Dialog box.So when i tried to call the constructor of Login from Main it was generating an error regarding the arguments passed.I have not used any arguments when i called. when i looked at the code, the function was declared as public Login(java.awt.Frame parent,boolean modal)so when i call it from main(),what am i supposed to do ?
View 3 Replies View Relatedthe compiler (g++ 4.4.5) does not recognize PRE as a type in the following code:
Code:
enum mode {PRE, IN, POST};
class tree
[code]...
I wrote a little Bash script which accepts two values -- sender address and recipient address -- and finds any instances of mail sent from sender to recipient in /var/log/maillog. The script works fine, but it seems to be very inefficient. I'm just wondering how I can optimize it.
Code:
Example:
Code:
Again, it seems to work fine, but the script greps through /var/log/maillog three times -- first to find the sender; second to see if it's also going to the desired recipient; finally to view all instances of the message ID in the logs. This seems redundant and inefficient.
I'm trying to solve this problem, but always get Time limit exceeded. I've tried my best but still can't get under time limit. Could you please give me some hint about it?
Code:
#include <iostream>
#include <cmath>
[code]...
I tried to summarize the this as best as possible in the title. I am writing an initial value problem solver in the most general way possible. I start with an arbitrary number of initial values at arbitrary locations (inside a boundary.) The first part of my program creates a mesh/grid (I am not sure which is the correct nuance), with N points total, that contains all the initial values. My goal is to optimize the mesh such that the spacing is as uniform as possible. My solver seems to work half decently (it needs some more obscure debugging that is not relevant here.)
I am starting with one dimension. I intend to generalize the algorithm to an arbitrary number of dimensions once I get it working consistently. I am writing my code in fortran, but feel free to reply with pseudocode or the language of your choice.Allow me to elaborate with an example:Say I am working on a closed interval [1,10]
xmin=1
xmax=10
Say I have 3 initial points: xmin, 5 and xmax
num_ivc=3
known(num_ivc)=[xmin,5,xmax] //my arrays start at 1. Assume "known" starts sorted
I store my mesh/grid points in an array called coord. Say I want 10 points total in my mesh/grid.
N=10
coord(10)
Remember, all this is arbitrary--except the variable names of course. The algorithm should set coord to {1,2,3,4,5,6,7,8,9,10} Now for a less trivial example:
num_ivc=3
known(num_ivc)=[xmin,5.5,xmax
or just
num_ivc=1
known(num_ivc)=[5.5]
Now, would you have 5 evenly spaced points on the interval [1, 5.5] and 5 evenly spaced points on the interval (5.5, 10]? But there is more space between 1 and 5.5 than between 5.5 and 10. So would you have 6 points on [1, 5.5] followed by 4 on (5.5 to 10]. The key is to minimize the difference in spacing.I have been working on this for 2 days straight and I can assure you it is a lot trickier than it sounds. I have written code that
only works if N is large
only works if N is small
only works if it the known points are close together
[code]....
So as you can see, I have coded the gamut of almost-solutions. I cannot figure out a way to get it to perform equally well in all possible scenarios (that is, create the optimum spacing.)
I don't know if this is the best place to ask this question. This question arose when I had a g++ compilation error: error: expected constructor, destructor, or type conversion before '.' token The above message can be correctly displayed in urxvt or xterm. But in mrxvt the '.' part can't be displayed correctly. Then I noticed that the quote signs are actually different from the usual ones and there seems no way to type ' ' from the keyboard. What are the differences and how to make mrxvt to display ' ' correctly. I found mrxvt very good and easy to configure.
View 4 Replies View RelatedI am working on optimizing the iptables. I came across some way of optimizing the rules by removing the redundant rules and merging the rules . Is there any other way to increase the optimization of iptables ?The network that we applied the iptables is a simple LAN network. (College Network)
View 1 Replies View RelatedI have just bought a digital-to-analog converter, this one to be exact, along with an amplificator and two speakers. I'd like to get the most of my Ubuntu, a good sound (what player can I use ?) and to know wether I need to do some extra changes in the kernel (OSS / PulseAudio / ALSA ?) or not.
I wonder if my converter will be detected when i plug it in, and if any sound from my computer will be leaded to it automatically ? (I'll have the converter tomorrow). I believe its purpose is to replace the sound card, to provide a greater, pure sound. The converter is linked by USB by the way.
I have a friend who is using Ubuntu 10.10 Netbook Edition on their netbook and well they love it. However, I notice that at times (if not all the time) their internet is ridiculously slow. Yes, it's a 1 Mbps download connection, but I still think it's a little slow and at times I can't even get it to load a website. I'm thinking if I adjusted the MTU within Ubuntu, it might improve, if even only slightly. I believe the router is set to 1490 or 1500, I haven't really looked yet.
View 3 Replies View RelatedI would like to ask how can I optimize apache2 load on my dedicated server. I am hosting Facebook applications on it, but most users will get a Timed Out message when they try to access it. I was tinkering with MaxClients directive in apache2 config, and it got better, but still it's not best. Programmers are trying their best to optimize the applications at their side, but I am afraid this is an server issue.
View 2 Replies View RelatedI am running Ferdora 12 (constantine) 64 with Intel Xeon 3.2GHz processor + 12GB Ram. I am running this machine specifically for number chunching applications but it isnt running as fast as i thought it would! Are there any tips to optimizing the speed of processors in fedora?
View 7 Replies View RelatedI recently purchased a Western Digital 1TB USB hard drive to use for general data storage. I had thought about repartitioning it into 8 - 10 individual drives (most Linux users will doubtless understand the arguments for and against this) and reformatting them with another filesystem, probably ext2.
The unit actually consists of two 500GB drives that are presented by the internal controller as a single 1TB drive, and are formatted with the old HPFS/NTFS filesystem, so I'm a bit cautious about the possibility of my original plan confusing the drive's controller. Does anyone have any experience with these large drives, any thoughts about repartitioning/reformatting, and relevant criteria for optimizing their use?
Where can I find comprehensive information on optimizing Linux? I keep searching online but seem to get only to performance monitoring. I don't want to run a lighter version of Linux or upgrade my hardware! Just want to get my current distro and future ones I might install to run at its best.
View 8 Replies View RelatedOn my bare metal server, I get about 130MB/s read from a software RAID 10 array, but when reading the same file from a VM via NFS over the VirtIO interface,I only get about 40MB/s.
Furthermore, the process for the VM uses >180% CPU on the host, and ~40%, and the 5 min average is ~1.5 on the host and guest. I have dual E5620's so I'm disappointed that the transfer is so slow, as I was expecting at least 90MB/s.
I'm new to being a sysadmin, so if anyone has some tips I can use to increase the transfer rate, and possibility reduce the CPU load as well I'd appreciate it. I'm assuming that 130MB/s is the max speed of two 7.2k HDDs, but if there's any way I can squeeze any more out that would be great too.
System specs:
2x Intel Xeon E5620s @ 2.40Ghz
8GB of RAM @ 1066Mhz
4x 1TB Western Digital Black HDDs in RAID10
I have a dual boot on a netbook with windows and fedora13. When I am on my fedora boot and I try to watch streaming video it comes through in waves or not at all. I do not have the same problems on the alternate boot. There are other performance comparisons where the windows boot runs smoother and faster. Is there any work I can do in order to optimise my fedora boot in this capacity?
View 7 Replies View Relatedhow do you copy an entire line and add that copy at the end of the same line?
For example, sometimes I rename a collection of files with a command like:
"mv oldfilename newfilename;"
I am able to add "mv" at the beginning, the semicolon at the end and sometimes replace a word in the middle, but... how to change a line "oldfilename" into "oldfilename oldfilename"... that is already long time a mystery to me...
So I've come across several tips to optimize battery life on Linux. [URLs]. In addition to undervolting, I would like to underclock. Is there a way to control CPU speed outside of the BIOS via some software control in Linux... or some sort of boot manager? I would like to boot to linux using underclocked speeds and have Windows running full blast. Is there a way to run Linux completely in RAM? I have read that saves on power consumption from the hard drive.
View 4 Replies View Relatedim trying to get sed to read through a txt document that contains html and cant get it to copy over my code looks like Code: sed -n '/[width=468 height=60 border=0 /></a></center><hr>]/,/[<br clear=left><hr>]/p' 1.txt > 2.txt This is the code that seemed to have the best chance of working but still all it does is copy the whole txt document over instead of between these 2 expressions
View 3 Replies View RelatedI am trying to copy content of single folder to multiple destination simultaneously using tar and FIFO. here is the source code
mkfifo bin1.fifo
tar -C bin -cf - . | tee bin1.fifo | tar -C bin2 -xf - &
tar -C bin1 -xf bin1.fifo
[code]....
I need to copy text from screen of one workspace to a file in another of a different user.My x-windows is a tad rusty but a quick review leads me to believe this can be done.
View 8 Replies View RelatedI am working on a Linux embedded C++ project. When I do an install, all of the header files are copied into the target at /usr/include/.My question is, why would the target ever need the C++ header files? It seems to me all the target needs is the executables and the library *.so files.I want to remove the installation of header files into the target but I'm afraid I'm missing something.
View 3 Replies View RelatedI just want to copy the content from Wikipedia. Daily i want to do it. But this should be done automatically. can anyone tel me how to do this in php? is there any function to copy the content of any article?
View 1 Replies View RelatedAfter searching I cant find script that can deal with directories. All the found scripts work file to file and not directory to directory. Someone know script that can deal with all this situation?
View 8 Replies View RelatedI have this code:
Code:
original_content=${content[@]};
echo ${#content[@]} # is 23
echo ${#original_content[@]} # is 1
I'd expect original_content should be copy of content. How to copy array?
I just want to copy the content from Wikipedia. Daily i want to do it. But this should be done automatically. can anyone tel me how to do this in php? is there any function to copy the content of any article?
View 3 Replies View RelatedI having a hard time figuring out why this code works in an interactive ipython shell, but it gives a blank clipboard when run in a bash terminal.
Code:
#! /usr/bin/python2.6
#
[code]...
I have the following code and would like to copy all the found files within the if then loop.
Code:
I can pipe it to a file then run a smbclient get on the file listing but there must be a better way to do this.
I have been searching for a solution to the following problem:
When my distro of choice updates Firefox web browser, the directory name is '/usr/lib/firefox-<version>'.
The problem here is that the directory name is dynamic by nature and doesn't allow a simple static solution, e.g.
'cp -rf /usr/local/files/bookmarks.html /usr/lib/firefox/defaults/profile'.
The same quandary applies when adding extensions, changing prefs etc.
I have looked at the following commands:-
find, sed, xargs, grep, awk, fprint.
Unfortunately my grasp of syntax and programming is very simple at best.