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  • Problems using (building?) native gem extensions on OS X

    - by goodmike
    I am having trouble with some of my rubygems, in particular those that use native extensions. I am on a MacBookPro, with Snow Leopard. I have XCode 3.2.1 installed, with gcc 4.2.1. Ruby 1.8.6, because I'm lazy and a scaredy cat and don't want to upgrade yet. Ruby is running in 32-bit mode. I built this ruby from scratch when my MBP ran OSX 10.4. When I require one of the affected gems in irb, I get a Load Error for the gem extension's bundle file. For example, here's nokogigi dissing me: > require 'rubygems' = true > require 'nokogiri' LoadError: Failed to load /usr/local/lib/ruby/gems/1.8/gems/nokogiri-1.4.1/lib/nokogiri/nokogiri.bundle This is also happening with the Postgres pg and MongoDB mongo gems. My first thought was that the extensions must not be building right. But gem install wasn't throwing any errors. So I reinstalled with the verbose flag, hoping to see some helpful warnings. I've put the output in a Pastie, and the only warning I see is a consistent one about "passing argument n of ‘foo’ with different width due to prototype." I suspect that this might be an issue from upgrading to Snow Leopard, but I'm a little surprised to experience it now, since I've updated my XCode. Could it stem from running Ruby in 1.8.6? I'm embarrassed that I don't know quite enough about my Mac and OSX to know where to look next, so any guidance, even just a pointer to some document I couldn't find via Google, would be most welcome. Michael

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  • Internet explorer, Safari and Chrome problems with displaying @font-face rules.

    - by Antonio
    Hy guys, I've a problem with IExplorer, Chrome, Safari etc.. Only Firefox works perfectly with all of this @font-face rules: In Css: @font-face { font-family: Calibri; src: url('Calibri.ttf'); } @font-face { font-family: HAND; src: url('http://www.mydomain.org/css/HAND.eot'); src: url("HAND.ttf"); } #side_text { position:relative; width:330px; height:800px; float:left; margin-left:25px; margin-top:30px; } #side_text p { font-family: HAND; font-size: 18pt; text-align:left; color:#f3eee1; } In .html <div id="side_text"> text text text text text text text text I'ven't any problem with Calibri font, maybe because it's installed on os. The HAND font it's the problem. Moreover, IExplorer don't take any customs write in css (color, font-size, align..) That's all, hope to find a solution.. or I'll gone crazy :( Ps: I converted the .ttf font to eot with two different online converter - Sorry for spam :/ (http://ttf2eot.sebastiankippe.com) www.kirsle.net/wizards/ttf2eot.cgi because I've problem to execute ttf2eot on google code Thanks a lot guys!!

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  • what's the UNC path for local computer from a remote machine ?

    - by KaluSingh Gabbar
    I am writing a small utility program in IronPython to install applications on remote machine using managementclass which uses WMI. Now, the script would install an application on Machine_B from Machine_A, it works fine as long as you have the msi file on the local drive of the Target machine (Machine_B, in this case). I want to be able to do same thing with .msi file being on the Host (Machine_A) machine. network_scope = r"\\%Machine_B\root\cimv2" scope = ManagementScope(network_scope, options) scope.Connect() mp = ManagementPath("Win32_Product") ogo = ObjectGetOptions() mc = ManagementClass(scope, mp, ogo) inParams = mc.GetMethodParameters ("Install") inParams["PackageLocation"] = r"C:\installs\python-3.1.1.msi" inParams["AllUsers"] = True retVal = mc.InvokeMethod ("Install", inParams, None) print retVal ["ReturnValue"].ToString() PROBLEM : [Machine A] --- Where I am running the script, and want to host the .msi file [Machine B] --- where I want to install the application So, How can I define the UNC path for local machine ? what will be inParams["PackageLocation"] = ??

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  • Is the recent trend toward widescreen (16:9) computer monitors a plus or minus for programmers?

    - by DanM
    It's almost gotten to the point where you can't buy a conventional (4:3) monitor anymore. Pretty much everything is widescreen. This is fine for watching movies or TV, but is it good or bad for programming? My initial thoughts on the issue are that widescreens are a net negative for programmers. Here are some of the disadvantages I see: Poor space utiliziation One disadvantage of widescreens you can't argue with is that they offer poor space utilization for the amount of total pixels you get. For example, my Thinkpad, which I bought just before the widescreen craze, has a 15" monitor with a native resolution of 1600 x 1200. The newer 15.4" Thinkpads run at most 1680 x 1050. So (if you do the math) you get fewer pixels in a wider (but not shorter) package. With desktop monitors, you pay a price in terms of desk space used. Two 1680 x 1050 monitors will simply take up more of your desk than two 1600 x 1200 monitors (assuming equal dot pitch). More scrolling If you compare a 1680 x 1050 monitor to a 1600 x 1200 monitor, you get 80 extra pixels of width but 150 fewer pixels of height. The height reduction means you lose approximately 11 lines of code. That's less you can see on the screen at one time and more scrolling you have to do. This harms productivity, maybe not dramatically, but insidiously. Less room for wide panels Widescreens also mean you lose space for wide but short panels common in programming environments. If you use Visual Studio, for example, your code window will be that much shorter when viewing the Find Results, Task List, or Error List (all of which I use frequently). This isn't to say the 80 pixels of extra width you get with widescreen would never be useful, but I tend to keep my lines of code short, so seeing more lines would be more valuable to me than seeing fewer, longer lines. What do you think? Do you agree/disagree? Are you now using one or more widescreen monitors for development? What resolution are you running on each? Do you ever miss the height of the traditional 4:3 monitor? Would you complain if your monitors were one inch narrower but two inches taller?

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  • Nhibernate Migration from 1.0.2.0 to 2.1.2 and many-to-one save problems

    - by Meska
    Hi, we have an old, big asp.net application with nhibernate, which we are extending and upgrading some parts of it. NHibernate that was used was pretty old ( 1.0.2.0), so we decided to upgrade to ( 2.1.2) for the new features. HBM files are generated through custom template with MyGeneration. Everything went quite smoothly, except for one thing. Lets say we have to objects Blog and Post. Blog can have many posts, so Post will have many-to-one relationship. Due to the way that this application operates, relationship is done not through primary keys, but through Blog.Reference column. Sample mapings and .cs files: <?xml version="1.0" encoding="utf-8" ?> <id name="Id" column="Id" type="Guid"> <generator class="assigned"/> </id> <property column="Reference" type="Int32" name="Reference" not-null="true" /> <property column="Name" type="String" name="Name" length="250" /> </class> <?xml version="1.0" encoding="utf-8" ?> <id name="Id" column="Id" type="Guid"> <generator class="assigned"/> </id> <property column="Reference" type="Int32" name="Reference" not-null="true" /> <property column="Name" type="String" name="Name" length="250" /> <many-to-one name="Blog" column="BlogId" class="SampleNamespace.BlogEntity,SampleNamespace" property-ref="Reference" /> </class> And class files class BlogEntity { public Guid Id { get; set; } public int Reference { get; set; } public string Name { get; set; } } class PostEntity { public Guid Id { get; set; } public int Reference { get; set; } public string Name { get; set; } public BlogEntity Blog { get; set; } } Now lets say that i have a Blog with Id 1D270C7B-090D-47E2-8CC5-A3D145838D9C and with Reference 1 In old nhibernate such thing was possible: //this Blog already exists in database BlogEntity blog = new BlogEntity(); blog.Id = Guid.Empty; blog.Reference = 1; //Reference is unique, so we can distinguish Blog by this field blog.Name = "My blog"; //this is new Post, that we are trying to insert PostEntity post = new PostEntity(); post.Id = Guid.NewGuid(); post.Name = "New post"; post.Reference = 1234; post.Blog = blog; session.Save(post); However, in new version, i get an exception that cannot insert NULL into Post.BlogId. As i understand, in old version, for nhibernate it was enough to have Blog.Reference field, and it could retrieve entity by that field, and attach it to PostEntity, and when saving PostEntity, everything would work correctly. And as i understand, new NHibernate tries only to retrieve by Blog.Id. How to solve this? I cannot change DB design, nor can i assign an Id to BlogEntity, as objects are out of my control (they come prefilled as generic "ojbects" like this from external source)

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  • Problems and solution for Developing a connected web and desktop application?

    - by Taz
    hi, I am trying to develop a web application(Using ASP.NET and c#) that uses a specific database hosted on web server. I will have another desktop application that will use a local database. Both databases have same structure and data at start up. Then databases will change when users add data to web application and an employee adds data to the desktop application. After a while I have to sync both databases. What will be best way to do this? Is there any opensource example/ starter kit to start with? Thanks.

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  • If OOP makes problems with large projects, what doesn't?

    - by osca
    I learned Python OOP at school. My (good in theory, bad in practice) informatics told us about how good OOP was for any purpose; Even/Especially for large projects. Now I don't have any experience with teamwork in software development (what a pity, I'd like to program in a team) and I don't know anything about scaling and large projects either. Since some time I'm reading more and more about that object-oriented programming has (many) disadvantages when it comes to really big and important projects/systems. I got a bit confused by that as I always thought that OOP helped you keep large amounts of code clean and structured. Now why should OOP be problematic in large projects? If it is, what would be better? Functional, Declarative/Imperative?

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  • Windows 7 BSOD, safe mode working,

    - by mil0ck
    I need help getting my dualboot with Windows 7 and Ubuntu 12.04 to work, and since I'm not to experienced with computers I've been pretty dumb. Here's what I've done, quite shortend though: First removed a Ubuntu 10.04 partion, and replaced bootloader using EasyBCD Installed Ubuntu 12.04 on same partion as before Decided I need more space so I shrinked my C: partion (Windows partion) using Here, after rebooting my computer, I was stuck a grub rescue, when booting up the computer I fixed that by using SuperGrubDisk Rescatux and then using my Windows Vista install disk to repair the computer (computer is using Windows 7) I know re-installed Ubuntu 12.04 on the linux partion and got the GRUB-bootloader working Then, after using my computer for several hours, I installed beta drivers (version 304.79) for my GeForce GTS 240 and then rebooted my computer. At the first boot (after reboot) my computer just crashed, and here I am When trying to boot Windows 7 now I get a Blue Screen Of Death. I can though boot in to safe mode with everything working. I have uninstalled the beta drivers and installed the same one as before but still the same problem. I have tried all the commands in Bootrec.exe and none is working. I can't neither find an OS when using Bootrec.exe/ScanOs. I have also tried running: sfc/scannow and that comes out clean. Short: My harddrive and files seems to be intact but when booting I get bluescreen. I can though boot in to safemode with everything working. I need help Thanks to anyone who even took the time to read that. //mil0ck

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  • What category of combinatorial problems appear on the logic games section of the LSAT?

    - by Merjit
    There's a category of logic problem on the LSAT that goes like this: Seven consecutive time slots for a broadcast, numbered in chronological order I through 7, will be filled by six song tapes-G, H, L, O, P, S-and exactly one news tape. Each tape is to be assigned to a different time slot, and no tape is longer than any other tape. The broadcast is subject to the following restrictions: L must be played immediately before O. The news tape must be played at some time after L. There must be exactly two time slots between G and P, regardless of whether G comes before P or whether G comes after P. I'm interested in generating a list of permutations that satisfy the conditions as a way of studying for the test and as a programming challenge. However, I'm not sure what class of permutation problem this is. I've generalized the type problem as follows: Given an n-length array A: How many ways can a set of n unique items be arranged within A? Eg. How many ways are there to rearrange ABCDEFG? If the length of the set of unique items is less than the length of A, how many ways can the set be arranged within A if items in the set may occur more than once? Eg. ABCDEF = AABCDEF; ABBCDEF, etc. How many ways can a set of unique items be arranged within A if the items of the set are subject to "blocking conditions"? My thought is to encode the restrictions and then use something like Python's itertools to generate the permutations. Thoughts and suggestions are welcome.

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  • How can I solve NP complete problems in erlang?

    - by Yadira Suazo
    Hi, I already have my operators for, by example, eat banana problem [#op{ action = [climb, on, {object}], preconds = [[at, {place}, {object}], [at, {place}, me], [on, floor, me], [on, floor, {object}], [large, {object}]], add_list = [[on, {object}, me]], del_list = [[on, floor, me]] }, But how can I use it in the function solve(Problem, depth_first, []). And depth_first (Problem, Start) - search_tree(Problem, container.stack, Start).

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  • Does lamda in List.ForEach leads to memory leaks and performance problems ?

    - by Monomachus
    I have a problem which I could solve using something like this sortedElements.ForEach((XElement el) => PrintXElementName(el,i++)); And this means that I have in ForEach a lambda which permits using parameters like int i. I like that way of doing it, but i read somewhere that anonymous methods and delegates with lambda leads to a lot of memory leaks because each time when lambda is executed something is instantiated but is not released. Something like that. Could you please tell me if this is true in this situation and if it is why?

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  • how to restrict a web portal to a particular computer?

    - by ZX12R
    I am in the process of creating a Ruby on rails portal This portal requires a lot of data feeding by the site owner's back-office personnel. My client has this problem : the office staff should not be able to access the back office interface from any other than his office computers I have no idea how to achieve this. Is there a method for this? Thanks in advance.

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  • Recover windows cached domain password

    - by theguy
    I have a computer from another small organization that works with our school. It was previously joined to another domain from elsewhere. The organization doesn't have an IT person so they didn't think of what they needed to do about the information on the computer before they moved it to our school. The previous user of the computer is no longer with the organization so no information about the password. The computer has information that needs to be accessed and programs so putting the hard drive on another computer and grabbing the information is a no go as I need the computer itself to be working as well. The computer is running Windows Vista Business Edition and is joined to a domain with a cached profile. The admin accounts are disabled by GPO. I've been asked to see if I could recover the password but running ophcrack gave me no hits on the cached profile. I'm not too familiar with password recovery tools that would work on a cached profile from a domain so I'm looking for answers here. Any other suggestions? Preferably something free as we're a small school and an easy to use liveCD solution like ophcrack would be appreciated.

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  • jQuery i++ and i-- problems ... what on earth???

    - by michael
    Could someone please tell me what I am doing wrong? I'm not a newbie at programming but I feel like it tonight! Every time I increment the incrementing variable it throws a fit! When add one to it, it behaves fine, but if I try to add one more to it it wants to add 2 more. And then if I try to de-increment it wants to subtract from the original number that it was assigned to. I've tried: i++; i = i+1; i = i++; Nothing seems to work. It's got to be a stupid mistake. Press the buttons to increment and de-increment. http://michaelreynolds.net/iphone/ here's the code: var dayNum = 30; //---------------------------------------------------------------------- $.jQTouch({ icon: 'dailyqoteicon.png', statusBar: false, initializeTouch: 'a.touch' }); //---------------------------------------------------------------------- $(document).ready(function(){ //$(function(){}); $(function(){ $('a.touch').swipe( function(event, info){ //alert("jQTouch swipe event"); //alert(info.direction); }); }); $(function updateVerse(){ //alert("updateVerse called"); $.ajax({ type: "GET", dataType: 'JSON', data: 'day='+ dayNum, url: 'forward.php', success: function(data){ var obj = $.parseJSON(data); $("h2.quote").html(""); $("h3.reference").html(""); $("h2.quote").append(obj.quote); $("h3.reference").append(obj.reference, " ", obj.version); //$("span.version").append(obj.version); //----------------------------------- // JSON string {"id":"1","quote":"For to me, to live is Christ, and to die is gain","reference":"Philippians 1:21","version":"NKJV"} }, error: function(request, error){ alert("problem retrieving json data string"); } }); function addDayNum(){ dayNum = dayNum + 1; //dayNum = dayNum++; } function subDayNum(){ dayNum = dayNum - 1; //dayNum = dayNum--; } $("div#header a.next").tap( function(){ addDayNum(); //dayNum++;// doesn't work at all //dayNum = dayNum + 1;//doesn't work at all updateVerse(); //alert(dayNum); //alert("next clicked"); }); $("div#header a.prev").live('click', function(){ subDayNum(); //dayNum--;//doesn't work at all //dayNum = dayNum - 1;// doesn't work at all updateVerse(); //alert(dayNum); //alert("previous clicked"); }); }); });

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  • Converting my lightweight MySQL DB wrapper into MySQLi. Pesky Problems

    - by Chaplin
    Here is the original code: http://pastebin.com/DNxtmApY. I'm not that interested in prepared statements at the moment, I just want this wrapper updating to MySQLi so once MySQL becomes depreciated I haven't got to update a billion websites. Here is my attempt at converting to MySQLi. <? $database_host = "127.0.0.1"; $database_user = "user"; $database_pass = "pass"; $database_name = "name"; $db = new database($database_host, $database_user, $database_pass, $database_name); class database { var $link, $result; function database($host, $user, $pass, $db) { $this->link = mysqli_connect($host, $user, $pass, $db) or $this->error(); mysqli_select_db($db, $this->link) or $this->error(); } function query($query) { $this->result = mysqli_query($query, $this->link) or $this->error(); $this->_query_count++; return $this->result; } function countRows($result = "") { if ( empty( $result ) ) $result = $this->result; return mysqli_num_rows($result); } function fetch($result = "") { if ( empty( $result ) ) $result = $this->result; return mysqli_fetch_array($result); } function fetch_num($result = "") { if ( empty( $result ) ) $result = $this->result; return mysqli_fetch_array($result, mysqli_NUM); } function fetch_assoc($result = "") { if ( empty( $result ) ) $result = $this->result; return mysqli_fetch_array($result, mysqli_ASSOC); } function escape($str) { return mysqli_real_escape_string($str); } function error() { if ( $_GET["debug"] == 1 ){ die(mysqi_error()); } else { echo "Error in db code"; } } } function sanitize($data) { //apply stripslashes if magic_quotes_gpc is enabled if(get_magic_quotes_gpc()) $data = stripslashes($data); // a mysqli connection is required before using this function $data = trim(mysqli_real_escape_string($data)); return $data; } However it chucks all sorts of errors: Warning: mysql_query(): Access denied for user 'www-data'@'localhost' (using password: NO) in /home/count/Workspace/lib/classes/user.php on line 7 Warning: mysql_query(): A link to the server could not be established in /home/count/Workspace/lib/classes/user.php on line 7 Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in /home/count/Workspace/lib/classes/user.php on line 8 Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, object given in /home/count/Workspace/lib/classes/database.php on line 31

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  • SVG rotation animation having problems on chrome for jelly bean, is there a workaround?

    - by Metalskin
    I've got a strange problem with chrome on jellybean running svg animations triggered from javascript. This JSFiddle example works fine on chrome and firefox on linux, but when I run it on android with chrome I get the final step of the animation painted at the beginning of the animation. I've tried this on both an Nexus 7 and Transformer Prime, they both have the problem. I've tested using firefox on the android devices and the problem doesn't exist. So I'm presuming that it's a defect with chrome. However I've seen other animations using svg that do not have this problem in chrome on jellybean. Is anyone aware of a way to get around this problem, or is there something that I'm doing in my animation/js that is a possible cause of the problem? I've now created a bug report at code.google.com, however I still need a workaround, if anyone can help me (or in case I'm doing something stupid). I've now discovered that this is reproducible on chrome for linux (and I suspect windows). If you click on the button to start the animation before the previous animation has completed then the problem occurs. In this case the hand is drawn at the end of the 45 degree sweep before it starts the sweep. I now suspect that I should be calling something to stop the animation before I change the animation. Anyway, hopefully someone can resolve this problem.

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  • C++'s std::string pools, debug builds? std::string and valgrind problems

    - by Den.Jekk
    Hello, I have a problem with many valgrind warnings about possible memory leaks in std::string, like this one: 120 bytes in 4 blocks are possibly lost in loss record 4,192 of 4,687 at 0x4A06819: operator new(unsigned long) (vg_replace_malloc.c:230) by 0x383B89B8B0: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.8) by 0x383B89C3B4: (within /usr/lib64/libstdc++.so.6.0.8) by 0x383B89C4A9: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.8) I'm wondering: does std::string (GCC 4.1.2) use any memory pools? if so, is there any way to disable the pools (in form of a debug build etc.)? Regards, Den

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  • Problems with Threading in Python 2.5, KeyError: 51, Help debugging?

    - by vignesh-k
    I have a python script which runs a particular script large number of times (for monte carlo purpose) and the way I have scripted it is that, I queue up the script the desired number of times it should be run then I spawn threads and each thread runs the script once and again when its done. Once the script in a particular thread is finished, the output is written to a file by accessing a lock (so my guess was that only one thread accesses the lock at a given time). Once the lock is released by one thread, the next thread accesses it and adds its output to the previously written file and rewrites it. I am not facing a problem when the number of iterations is small like 10 or 20 but when its large like 50 or 150, python returns a KeyError: 51 telling me element doesn't exist and the error it points out to is within the lock which puzzles me since only one thread should access the lock at once and I do not expect an error. This is the class I use: class errorclass(threading.Thread): def __init__(self, queue): self.__queue=queue threading.Thread.__init__(self) def run(self): while 1: item = self.__queue.get() if item is None: break result = myfunction() lock = threading.RLock() lock.acquire() ADD entries from current thread to entries in file and REWRITE FILE lock.release() queue = Queue.Queue() for i in range(threads): errorclass(queue).start() for i in range(desired iterations): queue.put(i) for i in range(threads): queue.put(None) Python returns with KeyError: 51 for large number of desired iterations during the adding/write file operation after lock access, I am wondering if this is the correct way to use the lock since every thread has a lock operation rather than every thread accessing a shared lock? What would be the way to rectify this?

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  • Java: any problems/negative sides of keeping SoftReference to ArrayList in HttpSession?

    - by westla7
    My code is doing the following (just as an example, and the reason that I specify package path to java.lang.ref.SoftReference is to note that it's not my own implementaiton :-): ... List<String> someData = new ArrayList<String>(); someData.add("Value1"); someData.add("Value2"); ... java.lang.ref.SoftReference softRef = new SoftReference(someData); ... HttpSession session = request.getSession(true); session.setAttribute("mySoftRefData", softRef); ... and later: ... java.lang.ref.SoftReference softRef = session.getAttribute("mySoftRefData"); if (softRef != null && softRef.get() != null) { List<String> someData = (List<String>)softRef.get(); // do something with it. } ... Any disadvantages? Which I do not see? Thank you!

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  • Basic problems (type inference or something else?) in Objective-C/Cocoa.

    - by Matt
    Hi, Apologies for how basic these questions are to some. Just started learning Cocoa, working through Hillegass' book, and am trying to write my first program (a GUI Cocoa app that counts the number of characters in a string). I tried this: NSString *string = [textField stringValue]; NSUInteger *stringLength = [string length]; NSString *countString = (@"There are %u characters",stringLength); [label setStringValue:countString]; But I'm getting errors like: Incompatible pointer conversion initializing 'NSUInteger' (aka 'unsigned long'), expected 'NSUInteger *'[-pedantic] for the first line, and this for the second line: Incompatible pointer types initializing 'NSUInteger *', expected 'NSString *' [-pedantic] I did try this first, but it didn't work either: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] On a similar note, I've only written in easy scripting languages before now, and I'm not sure when I should be allocing/initing objects and when I shouldn't. For example, when is it okay to do this: NSString *myString = @"foo"; or int *length = 5; instead of this: NSString *myString = [[NSString alloc] initWithString:"foo"]; And which ones should I be putting into the header files? I did check Apple's documentation, and CocoaDev, and the book I'm working for but without luck. Maybe I'm looking in the wrong places.. Thanks to anyone who takes the time to reply this: it's appreciated, and thanks for being patient with a beginner. We all start somewhere. EDIT Okay, I tried the following again: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] And it actually worked this time. Not sure why it didn't the first time, though I think I might have typed %d instead of %u by mistake. However I still don't understand why the code I posted at the top of my original post doesn't work, and I have no idea what the errors mean, and I'd very much like to know because it seems like I'm missing something important there.

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  • Problems with passing an anonymous temporary function-object to a templatized constructor.

    - by Akanksh
    I am trying to attach a function-object to be called on destruction of a templatized class. However, I can not seem to be able to pass the function-object as a temporary. The warning I get is (if the comment the line xi.data = 5;): warning C4930: 'X<T> xi2(writer (__cdecl *)(void))': prototyped function not called (was a variable definition intended?) with [ T=int ] and if I try to use the constructed object, I get a compilation error saying: error C2228: left of '.data' must have class/struct/union I apologize for the lengthy piece of code, but I think all the components need to be visible to assess the situation. template<typename T> struct Base { virtual void run( T& ){} virtual ~Base(){} }; template<typename T, typename D> struct Derived : public Base<T> { virtual void run( T& t ) { D d; d(t); } }; template<typename T> struct X { template<typename R> X(const R& r) { std::cout << "X(R)" << std::endl; ptr = new Derived<T,R>(); } X():ptr(0) { std::cout << "X()" << std::endl; } ~X() { if(ptr) { ptr->run(data); delete ptr; } else { std::cout << "no ptr" << std::endl; } } Base<T>* ptr; T data; }; struct writer { template<typename T> void operator()( const T& i ) { std::cout << "T : " << i << std::endl; } }; int main() { { writer w; X<int> xi2(w); //X<int> xi2(writer()); //This does not work! xi2.data = 15; } return 0; }; The reason I am trying this out is so that I can "somehow" attach function-objects types with the objects without keeping an instance of the function-object itself within the class. Thus when I create an object of class X, I do not have to keep an object of class writer within it, but only a pointer to Base<T> (I'm not sure if I need the <T> here, but for now its there). The problem is that I seem to have to create an object of writer and then pass it to the constructor of X rather than call it like X<int> xi(writer(); I might be missing something completely stupid and obvious here, any suggestions?

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