Search Results

Search found 4627 results on 186 pages for 'programmer quotes'.

Page 56/186 | < Previous Page | 52 53 54 55 56 57 58 59 60 61 62 63  | Next Page >

• SEO - Delimiter character for page title

  - by cept0

  I have noticed a few oddities recently with the titles of web pages in SERPs. However, it seems there are several main conventions: Contact Page - Joe Schmoe's Awesome Site // &#045; Hyphen Contact Page — Joe Schmoe's Awesome Site // &mdash; Em dash Contact Page | Joe Schmoe's Awesome Site // &#x007C; Vertical bar Contact Page « Joe Schmoe's Awesome Site // &laquo; Left double angle quotes Is there any reason to use one over the other?

  Read the article

• Why does add-apt-repository fail to add source repositories?

  - by Lorin Hochstein

  add-apt-repository throws an error if I try to add a source repository: This works: sudo add-apt-repository 'deb http://dl.ajaxplorer.info/repos/apt squeeze main' This fails with an error: sudo add-apt-repository 'deb-src http://dl.ajaxplorer.info/repos/apt squeeze main' Error: 'deb-src http://dl.ajaxplorer.info/repos/apt squeeze main' invalid Leaving off the quotes doesn't help: sudo add-apt-repository deb-src http://dl.ajaxplorer.info/repos/apt squeeze main Error: need a repository as argument

  Read the article

• Presentations & Training material OFM Summer Camps & Impressions & Feedback

  - by JuergenKress

  Thanks to all attendees who invested their time and utilized the opportunity to attend the Summer Camps! Due to high demand of our most of the trainings, we had a long waiting list with more numbers of partners who are keen to attend it. We would like to give our special thanks to all trainers, who delivered excellent workshops! Most of the presentations and course material have been posted on our SOA Community Workspace and WebLogic Community Workspace. You can access the content only if you are a registered community member. To register for the SOA Community please click here. You can register for the WebLogic Community here. To find out the first impressions of the event please visit our Facebook pages: www.facebook.com/WebLogicCommunity & www.facebook.com/soacommunity or Picasa Album Thanks for the excellent blog posts from AMIS Technology Blog & Middleware by Link Consulting. Let us know if you published a twitter blog on @soacommunity & @wlscommunity. We will be pleased to publish it in our Newsletters. WebLogic Course Quotes “Oracle trainings are the best” - Pedro Neto Novobas “Excellent training, well organized” - Pedro Antunh, Capgemini “This course dives you into Oracle WebLogic giving you a quick start on benefiting from Fusion Apps” - Leonardo Fernandes, Outsystems Additional Quotes “Thanks a lot again for organizing such a great and informative Summer Camp. Both training and networking were organized very professionally. I have gained tons of very useful Info, which will definitely help to increase quality of our future projects.” - Daniel Fasko fss-group.com “I didn’t get the chance yesterday to thank you for a most enjoyable and thoroughly educational time I had in Munich over the last few days.” - Jeroen Bakker Ordina “Just to congratulate you on a great event, not only today but also in the previous days of training. As we know, a very good organization and, as a native Portuguese that knows Lisbon very good, a nice choice of places to visit. Looking forward to come again next year.” Pedro Miguel Neto, Novobase. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: OFM Summer Camps,eduction,training,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

  Read the article

• Oracle Keynote Panel at AIIM - The Movie

  - by [email protected]

  I've uploaded the video of the Oracle keynote panel at AIIM. It's broken into a number of segments, and I've put some of the quotes in the comments area so you can follow the topics as you decide which one to view. You can see the video here. A big thanks to our panelists for their time and insights - Cindy Bixler of Embry Riddle Aeronautical Univerisity, Tom Showalter of JP Morgan Chase, Irfan Motiwala of Moodys Investments, and Monica Crocker of Land O' Lakes, and a special thanks to our moderator, Robert Shimp of Oracle.

  Read the article

• When does "proper" programming no longer matter?

  - by Kai Qing

  I've been a full time programmer for about 8 years now. Web based mostly, ranging in weird jobs for clients. Never anything I "want" to do. So my experience is limited to what I've been contracted to do, having no real incentive to master anything in particular. So here's my scenario and ultimately what I wonder about... I've been building an android game in my spare time. It's using the libgdx library so quite a bit of the heavy lifting is done for me. I don't read much of the docs cause unless it's in tutorial format I will just not care, and ultimately most of my questions have already been asked on stackoverflow. I get along fine and my game works as expected... Suspiciously well, even. So much so that I wonder why one should bother to be "proper" when coding if the end result is ultimately the same. To be more specific, I used a hashtable because I wanted something close to an associative array. Human readable key values. In other places to achieve similar things, I use a vector. I know libgdx has vector2 and vector3 classes, but I've never used them. When I come across weird problems and search stackoverflow for help, I see a lot of people just reaming the questions that use a certain datatype when another one is technically "proper." Like using an ArrayList because it does not require defined bounds versus re-defining an int[] with new known boundaries. Or even something trivial like this: for(int i = 0; i < items.length; i ++) { // do something } I know it evaluates item.length on every iteration. I just don't care. I know items will never be more than 15 to 20 items. So why bother caring if I evaluate items.length on every iteration? So I wonder - why does everyone get all up in arms over this? Who cares if I use a less efficient datatype to get the job done? I ran some tests to see how the app performs using the lazy, get it done fast and don't look back method I just described versus the proper, follow the tutorial and use the exact data types suggested by the community. The results: Same thing. Average 45 fps. I opened every app on the phone and galaxy tab. Same deal. No difference. My game is pretty graphic intensive. It's not like it's just a simple thing. I expected it to perform kind of badly since I don't care to optimize image assets or... well, you probably get the idea. I'm making the game for fun. As a joke, really. But in doing so I'm working outside the normal scope of my job, which is to always follow the rules and do it the right way. So to say, I am without bounds here and this has caused me to wonder why I ever really care to be "proper" So I guess my question to you is this: Is there a threshold when it no longer matters to be proper? Is there a lasting, longer term consequence to the lazy, get it done and don't look back route? Is it ok to say - "so long as it gets the job done, I don't care?" Disclaimer: When I program my game, I am almost always drunk. I do it to remember why I got into this stuff to begin with because the monotony of client based web work will make you hate being a programmer. I'm having a blast and my game is not crashing, tests well, performs well, looks good on all devices so far and has no noticeable negative impact on any of my testing devices. I expected failure because I was being so drunkenly careless with my code, but to my surprise, it had no noticeable impact. I am now starting to question the need to be careful. Help me regain the ability to care! ... or explain why it's not a bad thing to not care. Secondary disclaimer: I am aware of the benefits of maintainability. For myself and others. Agreed. But it's not like someone happening across my inefficient int[] loop won't know what it does. As an experienced programmer those kinds of things are just clear on sight. I document the complex stuff for myself knowing I was drunk and will probably need a reminder. Those notes would clarify any confusion for someone who might ever gaze upon my ridiculous game - though the reality is that either I maintain it myself or it fades into time. I'm ok with that. But if it doesn't slow the device down, or crash, then crossing the t's and dotting the i's might actually require more time than it's worth.

  Read the article

• Getting started with StreamInsight

  A quick-start to SQL Server StreamInsight and Complex Event Processing with a step-by-step example on stock quotes. Too many SQL Servers to keep up with?Download a free trial of SQL Response to monitor your SQL Servers in just one intuitive interface."The monitoringin SQL Response is excellent." Mike Towery.

  Read the article

• How to Add a Taskbar to the Desktop in Ubuntu 14.04

  - by Lori Kaufman

  If you’ve switched to Ubuntu from Windows, it may take some time to get used to the new and different interface. However, you can easily incorporate a familiar Windows feature, the Taskbar, into Ubuntu to make the transition easier. A tool called Tint2 provides a bar at the bottom of the Ubuntu Desktop that resembles the Windows Taskbar. We will show you how to install it and make it start every time you log into Ubuntu. NOTE: When we say to type something in this article and there are quotes around the text, DO NOT type the quotes, unless we specify otherwise. Press Ctrl + Alt + T to open a Terminal window. To install Tint2, type the following line at the prompt and press Enter. sudo apt-get install tint2 Type your password at the prompt and press Enter. The progress of the installation displays and then a message displays saying how much disk space will be used. When asked if you want to continue, type a “y” and press Enter. When the installation has finished, close the Terminal window by typing “exit” at the prompt and pressing Enter. Click the Search button at the top of the Unity bar. Start typing “startup applications” in the Search box. Items that match what you type start displaying below the Search box. When the Startup Applications tool displays, click the icon to open it. On the Startup Applications Preferences window, click Add. On the Add Startup Program dialog box, enter a name for the startup application. This name displays in the list on the Startup Applications Preferences window. Type “tint2” in the Command edit box, enter a description in the Comment edit box, if desired, and click Add. Tint2 is added as a startup program and will start every time you log into Ubuntu. Click Close to close the Startup Applications Preferences window. Log out and log back in to make the Taskbar available on the desktop. You do not need to reboot the computer for this change to take effect. Now, when you minimize a program, an icon for it displays on the Taskbar at the bottom of the screen, just like the Taskbar in Windows. If you decide that you don’t want the Taskbar to display every time you log into Ubuntu, you can uncheck the Tint2 startup program on the Startup Applications Preferences window. You don’t need to delete it from the list.

  Read the article

• Reflector is no longer going to be free - What do you think?

  - by simonsabin

  Redgate recently announced that the next version of reflector was no longer going to be free ( http://www.red-gate.com/products/dotnet-development/reflector/announcement ). Instead you will be changed $35 . Here is the FAQ about the decision http://www.red-gate.com/products/dotnet-development/reflector/announcement-faq As a side note it drives me nuts when a UK company quotes dollars on their website. Especially when I am in the UK and I use pounds. The more I think about this the more I don’t like...(read more)

  Read the article

• Announcement: ZFS Backup Appliance

  - by uwes

  Announcing Product Software Changes for Sun ZFS Backup Appliance Effective December 4th, 2012, Replication and Cloning software licenses are no longer mandatory purchases with Sun ZFS Backup Appliance.   Replication and Cloning are still available as optional additions on new Sun ZFS Backup Appliance quotes, or as additions to existing systems. For More Product Information Go To External: ZFS Storage Appliance Oracle.com page External: ZFS Storage Appliance Oracle Technical Network.com page External: Software download support.oracle.com page

  Read the article

• Unzip individual files from multiple zip files and extract those individual files to home directory

  - by James P.

  I would like to unzip individual files. These files have a .txt extension. These files also live within multiple zipped files. Here is the command I'm trying to use. unzip -jn /path/to/zipped/files/zipArchiveFile2011\*.zip /path/to/specific/individual/files/myfiles2011*.txt -d /path/to/home/directory/for/extract/ From my understanding, the -j option excludes directories and will extract only the txt files The -n option will not overwrite a file if it has already been extracted. I've also learned that the forward slash in /path/to/zipped/files/zipArchiveFile2011\*.zip is necessary to escape the wildcard (*) character. Here is sample of error messages I'm coming accross: Archive: /path/to/zipped/files/zipArchiveFile20110808.zip caution: filename not matched: /path/to/specific/individual/files/myfiles20110807.txt caution: filename not matched: /path/to/specific/individual/files/myfiles20110808.txt Archive: /path/to/zipped/files/zipArchiveFile20110809.zip caution: filename not matched: /path/to/specific/individual/files/myfiles20110810.txt caution: filename not matched: /path/to/specific/individual/files/myfiles20110809.txt I feel that I'm missing something very simple. I've tried using single quotes (') and double quotes (") around directory paths. But no luck.

  Read the article

• If spaces in filenames are possible, why do some of us still avoid using them?

  - by Chris W. Rea

  Somebody I know expressed irritation today regarding those of us who tend not to use spaces in our filenames, e.g. NamingThingsLikeThis.txt -- despite most modern operating systems supporting spaces in filenames. Non-technical people must look at filenames created by geeks and wonder where we learned English. So, what are the reasons that spaces in filenames are avoided or discouraged? The most obvious reason I could think of, and why I typically avoid it, are the extra quotes required on the command line when dealing with such files. Are there any other significant reasons, other than the practice being a vestigial preference? UPDATE: Thanks for all your answers! I'm surprised how popular this was. So, here's a summary: Six Reasons Why Geeks Prefer Filenames Without Spaces In Them It's irritating to put quotes around them when referenced on the command line (or elsewhere.) Some older operating systems didn't used to support them and us old dogs are used to that. Some tools still don't support spaces in filenames at all or very well. (But they should.) It's irritating to escape spaces when used where spaces must be escaped, such as URLs. Certain unenlightened services (e.g. file hosting, webmail) remove or replace spaces anyway! Names without spaces can be shorter, which is sometimes desirable as paths are limited.

  Read the article

• Export NFS path containing "-" (dash)

  - by qdot

  I'm in a bit of a pinch with NFS exports file. Specifically, I can't find a way to export a directory containing "-" in the path name. Manual (exports(5)) states: Also, each line may have one or more specifications for default options after the path name, in the form of a dash ("-") followed by an option list. The option list is used for all subsequent exports on that line only. It then states: If an export name contains spaces it should be quoted using double quotes. You can also specify spaces or other unusual character in the export name using a backslash followed by the character code as three octal digits. Unfortunately, that is not the case. Specifically, if the pathname contains "-", either verbatim, or with \055 or is enclosed in double quotes, it still refers to the name without "-" Any ideas? I have a large number of directories, all of the form /vol/buildsystem-s3c2440 /vol/buildsystem-tao3530 and I'd prefer to have them all available as nfs exports. Short of replacing the "-" with "_" everywhere in the scripts, can it be done with "-" ?

  Read the article

• Postfix won't pipe to PHP file through aliases file

  - by jfreak53

  I'm trying to pipe from postfix to a command. According to Postfix logs it worked, but when I check the command it didn't. This is a fresh postfix install. This is my alias file: # See man 5 aliases for format postmaster: root support: "| /usr/bin/php -q /var/www/pipe/pipe.php" I run sendmail [email protected] then type it and then on a separate line type . and it goes. I check the postfix log /var/log/mail.log and this is what it states: Nov 2 15:32:33 server3 postfix/local[13284]: 42C429E0B5: to=<[email protected]>, relay=local, delay=156, delays=156/0.01/0/0.05, dsn=2.0.0, status=sent (delivered to command: /usr/bin/php -q /var/www/pipe/pipe.php) So according to that it worked, but it doesn't. If I run echo 'text' | /usr/bin/php -q /var/www/pipe/pipe.php it does work just fine. Any ideas what I did wrong? I know piping is working, I originally checked it by running that command above WITHOUT the quotes, so just support: | /usr/bin/php -q /var/www/pipe/pipe.php What it did there was append my email header and all to the file pipe.php. So I know postfix was piping it, but when I put in the quotes it says it's going but it's not according to my script.

  Read the article

• Webserver python update script

  - by ThePyCoder

  So i have made this website on which you can trade stocks based on real stock quotes with virtual money. The stock quotes are in a MySQL database and are updated using a python script which runs every minute or so. Now, this works fine on my local machine with xampp but how about moving the project to a commercial web server? Basically I want my page hosted by a professional company but do those kind of servers support python scripts running in the background? Because a dedicated server would be to expensive and the script does some other sql tasks too so it can't be replaced by PHP or so... So, are there any good web hosting services out there who give me the possibility of running a script in the background and hosting a website in the foreground? For what server specifications do i have to look for? Thnx in advance! PS: I've done some research, and I found a python supporting web host WITH ssh support. Is that what I need? Or is the ssh not allowed to start processes?

  Read the article

• debugging C++ when compared to debugging C

  - by benjamin button

  HI, I am normally a C programmer. I do regularly debug C programs on unix environment using tools like gdb,dbx. i have never done debugging of big applications of C++. Is that much different from how we debug in C. theoretically i am quite good in C++ but have never got a chance to debug C++ programs. I am also not sure about what kind of technical problems we face in c++ which will lead a developer to switch on the debugger for finding out the problem. what are the common issues we face in C++ which will make debugger to be started what are the challenges that a c programmer might face while debugging a C++ program? Is it difficult and complex when compared to C?

  Read the article

• Why the following Java code has different outputs each time?

  - by Maxood

  I don't know about threads in Java. I like to know what is happening in this code because each time it runs, it produces a different output: public class TwoThreadsDemo{ public static void main(String[] args) { new SimpleThread("Java Programmer").start(); new SimpleThread("Java Programmer").start(); } } class SimpleThread extends Thread{ public SimpleThread(String str) { super(str); } public void run() { for (int i=0;i<10;i++) { System.out.println(i + " " + getName()); try { sleep((long)(Math.random()*1000)); } catch(InterruptedException e) { } } System.out.println("Done!" + getName()); } }

  Read the article

• Is MVVM pointless?

  - by joebeazelman

  Is orthodox MVVM implementation pointless? I am creating a new application and I considered Windows Forms and WPF. I chose WPF because it's future-proof and offer lots of flexibility. There is less code and easier to make significant changes to your UI using XAML. Since the choice for WPF is obvious, I figured that I may as well go all the way by using MVVM as my application architecture since it offers blendability, separation concerns and unit testability. Theoretically, it seems beautiful like the holy grail of UI programming. This brief adventure; however, has turned into a real headache. As expected in practice, I’m finding that I’ve traded one problem for another. I tend to be an obsessive programmer in that I want to do things the right way so that I can get the right results and possibly become a better programmer. The MVVM pattern just flunked my test on productivity and has just turned into a big yucky hack! The clear case in point is adding support for a Modal dialog box. The correct way is to put up a dialog box and tie it to a view model. Getting this to work is difficult. In order to benefit from the MVVM pattern, you have to distribute code in several places throughout the layers of your application. You also have to use esoteric programming constructs like templates and lamba expressions. Stuff that makes you stare at the screen scratching your head. This makes maintenance and debugging a nightmare waiting to happen as I recently discovered. I had an about box working fine until I got an exception the second time I invoked it, saying that it couldn’t show the dialog box again once it is closed. I had to add an event handler for the close functionality to the dialog window, another one in the IDialogView implementation of it and finally another in the IDialogViewModel. I thought MVVM would save us from such extravagant hackery! There are several folks out there with competing solutions to this problem and they are all hacks and don’t provide a clean, easily reusable, elegant solution. Most of the MVVM toolkits gloss over dialogs and when they do address them, they are just alert boxes that don’t require custom interfaces or view models. I’m planning on giving up on the MVVM view pattern, at least its orthodox implementation of it. What do you think? Has it been worth the trouble for you if you had any? Am I just a incompetent programmer or does MVVM not what it's hyped up to be?

  Read the article

• Tricks to avoid losing motivation?

  - by AareP

  Motivation is a tricky thing to upkeep. Once I thought that ambitious projects will keep programmer motivated, and too simple tasks will hinder his motivation. Now I have plenty of experience with small and large projects, desktop/web/database programming, c++/c#/java/php languages, oop/non-oop paradigms, day-job/free-time programming.. but I still can't answer the question of motivation. Which programming tasks I like, and which don't? It seems to depend on too many variables. One thing remains constant though. It's that starting everything from scratch is always more motivating than extending some existing system. Unfortunately it's hard to use this trick in productive programming. :) So my question is, what tricks programmer can use to stay motivated? For example should we use pen and paper as much as possible, in order not to get fed up with monitor and keyboard?

  Read the article

• jqgrid change pointer to hand

  - by Erwin

  Hi fellow programmer I want to change the pointer to hand when hovering over jqgrid's rows Is there an API for that?

  Read the article

• Tutorial for Quick Look Generator for Mac

  - by vgm64

  I've checked out Apple's Quick Look Programming Guide: Introduction to Quick Look page in the Mac Dev Center, but as a more of a science programmer rather than an Apple programmer, it is a little over my head (but I could get through it in a weekend if I bash my head against it long enough). Does anyone know of a good basic Quick Look Generators tutorial that is simple enough for someone with only very modest experience with Xcode? For those that are curious, I have a filetype called .evt that has an xml header and then binary info after the header. I'm trying to write a generator to display the xml header. There's no application bundle that it belongs to. Thanks!

  Read the article

• can you help me with 8068 project for Delphi .net please

  - by Lex Dean

  To find an Assembly programmer is very hard to help me I'm a established Delphi programmer that has an old copy of Delphi that is not .net And I have a *.dll that I'm converting into Delphi code for .net I'm on a big learning curve hear as i know little of .net yet. I've just got a computer with .net today!!!!!! I've run the *.dll through a dissembler and started putting jump links in as writing in Delphi assembly you do not do any addressing, just reference links. The file has fixed string structures (i think C++) ASCII & ANSI strings 1/ I do not know how to identify how the code references these structures 2/ and I do not know were the functions begin and what shape they look like The code is free for any one to look at their is not many functions in it. but I have to email it as stack over flow will not allow me to display it. Can you tech me or can you refer me to a friend you may know please to tech me lexdeanair at hotmail.com Best regards, Lex Dean from New Zealand I do not wish to pester any one

  Read the article

• What makes a bad programming language bad?

  - by sub

  We have all seen things like the typing system of JavaScript (There is a funny post including a truth table somewhere around here). I consider this one of the main things that makes a programming language bad. Other things that spring to mind: Bad Error messages (Either obfuscated so you can't figure out whats wrong, not existing or simply too long and red) The language wasn't planned and just grew uncontrolled in all directions (PHP?) The language encourages bad programm(er/ing) habits such as: Global variables everywhere, bad variable names Inconsistent naming conventions inside the language I can't come up with any more at the moment and would be very happy to read what you think about this. What shouldn't be missing in a language created to be as bad (from the perspectives of the programmer, the company that hires to programmer, the team leader and the customer) as possible? (I ask this because I'm designing a bad, experimental language at the moment)

  Read the article

• In your experience, what has inspired you to change a fundamental programming tool

  - by Dr J

  A lot of what I am working on is changing the mindset of a community of developers. Moving them from one tool to another, or to picking up a new tool. What are some of the suggested or recommended ways to get a community to pick up a new meme? While we can mandate tool usage, this is a last resort. I would rather have the developers move to any new tools of their own accord. I'm not a programmer, I need to understand why a programmer will move from one tool to another. Edited the title thanks to a fabulous comment! My world runs on Meme's, tipping points, and general pressures. This is why I needed to ask. And clarifying yet more- I am the middle manager needing to plan and manage an implementation and not a sales person.

  Read the article

• Good "Modelling & Simulation" book recommendations for programmers?

  - by Harry

  I'm a programmer, and have completely forgotten all the advanced engineering Math I studied ~20 years ago at school. I now have an urgent need to learn about Modelling and Simulation. Though the present context is Disease Modelling, I'm not sure if there's such a thing as 'general' modelling and simulation... with concepts / techniques / algorithms that could be used in just about any domain (and not just limited to biology, finance, trade, economic, weather, etc.) Would you have any recommendations that are easy to read by a semi-Math-literate programmer? Basically, I cannot afford to drown myself in too much Math and theory behind M & S, hence this post. Tia...

  Read the article

• Dealing with external processes

  - by Jesse Aldridge

  I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

  Read the article

< Previous Page | 52 53 54 55 56 57 58 59 60 61 62 63  | Next Page >