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  • C ++ virtual function

    - by user2950788
    masters of C++. I am trying to implement polymorphism in C++. I want to write a base class with a virtual function and then redefine that function in the child class. then demonstrate dynamic binding in my driver program. But I just couldn't get it to work. I know how to do it in C#, so I figured that I might have made some syntactical mistakes where I had used C#'s syntax in my C++ code, but these mistakes are not obvious to me at all. So I'd greatly appreciate it if you would correct my mistakes. class polyTest { public: polyTest(); virtual void type(); virtual ~polyTest(); }; void polyTest::type() { cout << "first gen"; } class polyChild: public polyTest { public: void type(); }; void polyChild::type() { cout << "second gen"; } int main() { polyChild * ptr1; polyChild * ptr2; ptr1 = new polyTest(); ptr2 = new polyChild(); ptr1 -> type(); ptr2 -> type(); }

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  • How do I call this function in CodeIgniter controller?

    - by Jason Shultz
    I've got this code, but I'm not sure I make it work: /** * Function: youtube data grabber * * @description : * @param $ : video code, url type (embed/url) * @return : data array * @author : Mamun. * @last -modified-by: Mamun. */ if (! function_exists('youtube_data_grabber')) { function youtube_data_grabber($video_code, $link_type = "embed") { if ($video_code != '') { if ($link_type == "embed") { $splited_data = explode("=",$video_code); $video_unique_code = substr(strrchr($splited_data[4],"/"),1,-strlen(strrchr($splited_data[4],"&"))); } else if ($link_type == "url") { $splited_data = explode("=",$video_code); $video_unique_code = substr($splited_data[1],0,-strlen(strrchr($splited_data[1],"&"))); } else { return; } // set feed URL $feedURL = 'http://gdata.youtube.com/feeds/api/videos/'.$video_unique_code; // read feed into SimpleXML object $sxml = simplexml_load_file($feedURL); return $sxml; } } } // End Youtube Function I'm not sure how to activate it is what I'm trying to say. I placed it in the controller and it's within a function for one of my pages. I don't have any syntax errors. I just don't know how to wake it up and make it work. I thought I could just put youtube_data_grabber('http://www.youtube.com/watch?v=LAcrFym10ZI', 'url'); but that didn't work. I got the code from here: http://bit.ly/b7YnDt and I have the zend functionality working. I tested it earlier and had no errors. I'm just having trouble with this youtube part. Any ideas?

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  • Add Hover display for table cell

    - by Jake
    I have a table, but it is not in a list format, meaning not a column/row format. I look for specific cells to add a hover event that displays a description of the cell. $("#TableID td").hover(function(){ //ifCellThatIWant $(this).append("<span>Message that was brought in</span>"); }, function(){ $(this).children().remove(); }); The problem is right now is that the hover displays a span(with info. inside) that I used jquery to append the span to the cell when mouseover, which expands the cell, which is an effect that I don't like or want. I'm Trying to have an out of the table look,but still be by the cell that triggered the event; because if the span has a lot of info. in it, expanding the cell dynamically will start to look pretty nasty. Also will help if I had some type of css direction on how will I make the display for the mouseover "description" span look nice. My mind thought is that a way to accomplish what I want is giver the appended span the position of my mouse cursor when hover, but not sure if its the right approach or what the syntax would look like.

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  • Is there a nice way of having static generic parameters is Java?

    - by Chris
    Hello, recently I'm writing some functions that I take from Haskell and translate into Java. One of the main problems I have is I cannot easily create a static property with a generic type. Let me explain by a little example... // An interface to implement functions public interface Func<P, R> { public R apply(P p); } // What I want to do... (incorrect in Java) public class ... { public static <T> Func<T, T> identity = new Func<T, T>() { public T apply(T p) { return p; } } } // What I do right now public class ... { private static Func<Object, Object> identity = new Func<Object, Object>() { public Object apply(Object p) { return p; } } @SuppressWarnings("unchecked") public static <T> Func<T, T> getIdentity() { return (Func<T, T>)identity; } } Are there any easier ways to do something like that? What kind of problems might arise if the syntax I used would be valid?

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  • Why would 1.000 subforms in a db be a bad idea?

    - by KlaymenDK
    Warm-up I'm trying to come up with a good way to implement customized document forms. It's for a tool to request access to applications; each application will want to ask its own specific questions. The thing is, we have one kind of (common) user who needs to fill in and submit documents based on templates, and another kind of (super) user who needs to be able to define what each template needs to contain. One implementation option would be to use a form (with the basic mandatory stuff), and have that form dynamically include a subform appropriate to the specific task at hand. The gist of the matter is that we could (=will!) quite easily end up having many hundreds of different subforms! (NB. These subforms will be maintained in an automated manner, but that is another topic that may be considered outside the scope of this Question.) Question It's common knowledge that having a lot of views in a Notes database is Bad Thing. But has anyone tried pushing the number of forms or subforms and made any experiences regarding performance?

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  • How to update attributes without validation

    - by Brian Roisentul
    I've got a model with its validations, and I found out that I can't update an attribute without validating the object before. I already tried to add on => :create syntax at the end of each validation line, but I got the same results. My announcement model have the following validations: validates_presence_of :title validates_presence_of :description validates_presence_of :announcement_type_id validate :validates_publication_date validate :validates_start_date validate :validates_start_end_dates validate :validates_category validate :validates_province validates_length_of :title, :in => 6..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :place, :in => 0..50, :on => :save validates_numericality_of :vacants, :greater_than_or_equal_to => 0, :only_integer => true validates_numericality_of :price, :greater_than_or_equal_to => 0, :only_integer => true My rake task does the following: task :announcements_expiration => :environment do announcements = Announcement.expired announcements.each do |a| #Gets the user that owns the announcement user = User.find(a.user_id) puts a.title + '...' a.state = 'deactivated' if a.update_attributes(:state => a.state) puts 'state changed to deactivated' else a.errors.each do |e| puts e end end end This throws all the validation exceptions for that model, in the output. Does anybody how to update an attribute without validating the model?

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  • Project Euler #119 Make Faster

    - by gangqinlaohu
    Trying to solve Project Euler problem 119: The number 512 is interesting because it is equal to the sum of its digits raised to some power: 5 + 1 + 2 = 8, and 8^3 = 512. Another example of a number with this property is 614656 = 28^4. We shall define an to be the nth term of this sequence and insist that a number must contain at least two digits to have a sum. You are given that a2 = 512 and a10 = 614656. Find a30. Question: Is there a more efficient way to find the answer than just checking every number until a30 is found? My Code int currentNum = 0; long value = 0; for (long a = 11; currentNum != 30; a++){ //maybe a++ is inefficient int test = Util.sumDigits(a); if (isPower(a, test)) { currentNum++; value = a; System.out.println(value + ":" + currentNum); } } System.out.println(value); isPower checks if a is a power of test. Util.sumDigits: public static int sumDigits(long n){ int sum = 0; String s = "" + n; while (!s.equals("")){ sum += Integer.parseInt("" + s.charAt(0)); s = s.substring(1); } return sum; } program has been running for about 30 minutes (might be overflow on the long). Output (so far): 81:1 512:2 2401:3 4913:4 5832:5 17576:6 19683:7 234256:8 390625:9 614656:10 1679616:11 17210368:12 34012224:13 52521875:14 60466176:15 205962976:16 612220032:17

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  • What is wrong with this php loop?

    - by Mark R
    I made a loop but it doesn't work. here's what I did: <?php if(is_tree('4')) { ?> <?php $show_after_p = 2; $content = apply_filters('the_content', $post->post_content); if(substr_count($content, '<p>') > $show_after_p) { $contents = explode("</p>", $content); $p_count = 1; foreach($contents as $content) { echo $content; if($p_count == $show_after_p) { ?> YOUR AD CODE GOES HERE < ? } echo "</p>"; $p_count++; } } ?> <?php else : ?> <?php the_content('<p class="serif">Read the rest of this page &raquo;</p>'); ?> <?php endif; } ?> I need to make it work but don't know how. I'm guessing it's a simple syntax error I'm not seeing?

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  • Linq-to-sql join/where?

    - by Curtis White
    I've the following table structures Users id Types id isBool UsersTypes userid types I want to select all the UserTypes based on id and isBool. I tried this query var q = from usertype in usertypes from type in types where type.isBool == false where userstypes.user == id select usertype; But this did not work as expected. My questions are: Why? Is there any difference in using the join on syntax vs where, where vs where cond1 && cond2? My understanding is query optimizer will optimize. Is there any difference in using where cond1 == var1 && cond2 == var2 with and without the parenthesis? This seems peculiar that it is possible to build this without parenthesis What type of query do I need in this case? I can see that I could do a subquery or use a group but not 100% sure if it is required. An example might be helpful. I'm thinking a subquery may be required in this case.

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  • printing out dictionnaires

    - by kyril
    I have a rather specific question: I want to print out characters at a specific place using the \033[ syntax. This is what the code below should do: (the dict cells has the same keys as coords but with either '*' or '-' as value.) coords = {'x'+str(x)+'y'+str(y) : (x,y) for x,y, in itertools.product(range(60), range(20))} for key, value in coords.items(): char = cells[key] x,y = value HORIZ=str(x) VERT=str(y) char = str(char) print('\033['+VERT+';'+HORIZ+'f'+char) However, I noticed that if I put this into a infinite while loop, it does not always prints the same characters at the same position. There are only slight changes, but it deletes some and puts them back in after some loops. I already tried it with lists, and there it seems to behave just fine, so I tend to think it has something todo with the dict, but I can not figure out what it could be. You can see the Problem in a console here: SharedConsole.I am happy for every tip on this matter. On a related topic: After the printing, some changes should be made at the values of the cells dict, but for reason unknown to me, the only the first two rules are executed and the rest is ignored. The rules should test how many neighbours (which is in population) are around the cell and apply the according rule. In my implemention of this I have some kind of weird tumor growth (which should not happen, as if there more than three around they should the cell should die) (see FreakingTumor): if cells_copy [coord] == '-': if population == 3: cells [coord] = '*' if cells_copy [coord] == '*': if population > 3: cells [coord] = '-' elif population <= 1: cells [coord] = '-' elif population == 2 or 3: cells [coord] = '*' I checked the population variable several times, so I am quite sure that is not the matter. I am sorry for the slow consoles. Thanks in advance! Kyril

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  • Project management software, available options

    - by canni
    Hey, sorry for posting this here, I know that this question better suites into SuperUser, but I would like to know answers from developers point of view. I have been using Indefero for project management etc. for some time, but I found that Indefero limitations are too big for my team. I'm searching project-management software that best suites this needs: Open-Source, but I can consider commercial apps GIT integration is mandatory, best if it can support multiple repos per project Time-tracking, good if it can have Gannt chart connected with issues etc. Issue, milestone, task tracking Good if it can be integrated with Gitosis, or have similar repository access control It must have an option, to setup on our own server Markdown syntax support is mandatory (or easy way to install plugin for this etc.) Issue tagging will be and advantage It will be used by developers team by 99% of time, but it has to have some simple interface, that clients can fill up bug reports etc. per project. It does not have to fill all this needs, but good if it can :) What options do You know, and can recommend?

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  • Is there an user-level accessible font table present in Linux?

    - by youngdood
    Hi again Stackoverflow! Since there is this: http://en.wikipedia.org/wiki/Code_page_437 For MSDOS, is there something similar for Linux systems? Is it possible to access that font data via userland program? I would actually just need an access to the actual bit patterns which define the font, and I would do the rendering myself. I'm fairly sure that something like this exists, but I haven't been able to find what exactly is it and how to access it. After all, e.g. text mode console font has to reside somewhere, and I really do hope it is "rawly" accessible somehow for a userland program. Before I forget, I'm programming my program in C, and have access only to the "standard" linux/posix development headers. The only thing I could came up with myself is to use the fonts in /usr/share/fonts, but having to write my own implementations to extract the data from there doesn't sound really an option; I would really want to achieve this with the least amount of bytes possible, so I feel I'm left with finding a standard way of doing this. It's not really feasible for me to store my own 8x8 ASCII-compatible font with the program either(it takes some 1024 bytes(128 chars * 8x8 bits) just to store the font, which is definitely unacceptable for the strict size limits(some < 1024 bytes for code+data) which I am working with), so being able to use the font data stored at the system itself would greatly simplify my task.

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  • How to reference input elements within a specific scope when there are multiple input elements of same kind?

    - by Will Merydith
    How do I select data for input elements within a specific scope? I have the same form multiple times (class "foo-form), and want to ensure I get the values for the hidden inputs within the scope of the form being submitted. Is the scope "this" implied? If not, what is the syntax for selecting input class "foo-text" within the scope of this? Feel free to point me to examples in the jquery docs - I could not find what I was looking for. $('.foo-form').submit(function() { // Store a reference to this form var $thisForm = $(this); }); <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> </form> <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> </form> <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> // user clicks this submit button </form>

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  • Adding functions to Java class libraries

    - by Eric
    I'm using a Java class library that is in many ways incomplete: there are many classes that I feel ought to have additional member functions built in. However, I am unsure of the best practice of adding these member functions. Lets call the insufficient base class A. class A { public A(/*long arbitrary arguments*/) { //... } public A(/*long even more arbitrary arguments*/) { //... } public int func() { return 1; } } Ideally, I would like to add a function to A. However, I can't do that. My choice is between: class B extends A { //Implement ALL of A's constructors here public int reallyUsefulFunction() { return func()+1; } } and class AddedFuncs { public int reallyUsefulFunction(A a) { return a.func()+1; } } The way I see it, they both have advantages and disadvantages. The first choice gives a cleaner syntax than the second, and is more logical, but has problems: Let's say I have a third class, C, within the class library. class C { public A func() { return new A(/*...*/); } } As I see it, there is no easy way of doing this: C c; int useful = c.func().reallyUsefulFunction(); as the type returned by C.func() is an A, not a B, and you can't down-cast. So what is the best way of adding a member function to a read-only library class?

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  • Potential Django Bug In QuerySet.query?

    - by Mike
    Disclaimer: I'm still learning Django, so I might be missing something here, but I can't see what it would be... I'm running Python 2.6.1 and Django 1.2.1. (InteractiveConsole) >>> from myproject.myapp.models import * >>> qs = Identifier.objects.filter(Q(key="a") | Q(key="b")) >>> print qs.query SELECT `app_identifier`.`id`, `app_identifier`.`user_id`, `app_identifier`.`key`, `app_identifier`.`value` FROM `app_identifier` WHERE (`app_identifier`.`key` = a OR `app_identifier`.`key` = b ) >>> Notice that it doesn't put quotes around "a" or "b"! Now, I've determined that the query executes fine. So, in reality, it must be doing so. But, it's pretty annoying that printing out the query prints it wrong. Especially if I did something like this... >>> qs = Identifier.objects.filter(Q(key=") AND") | Q(key="\"x\"); DROP TABLE `app_identifier`")) >>> print qs.query SELECT `app_identifier`.`id`, `app_identifier`.`user_id`, `app_identifier`.`key`, `app_identifier`.`value` FROM `app_identifier` WHERE (`app_identifier`.`key` = ) AND OR `app_identifier`.`key` = "x"); DROP TABLE `app_identifier` ) >>> Which, as you can see, not only creates completely malformed SQL code, but also has the seeds of a SQL injection attack. Now, obviously this wouldn't actually work, for quite a number of reasons (1. The syntax is all wrong, intentionally, to show the oddity of Django's behavior. 2. Django won't actually execute the query like this, it will actually put quotes and slashes and all that in there like it's supposed to). But, this really makes debugging confusing, and it makes me wonder if something's gone wrong with my Django installation. Does this happen for you? If so/not, what version of Python and Django do you have? Any thoughts?

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  • Convert IIS / Tomcat Web Application to a multi-server environment.

    - by bill_the_loser
    I have an existing web application built in .Net, running on IIS that leverages a java servlet that we have running on Tomcat 5.5. We need to scale the application and I'm confused about what relates to our situation and what we need to do to get the servlet running on multiple servers. Right now I have 4 servers that can each individually process results, it almost seems like all I should have to do is add the ajp13 worker processes from three additional machines to the machine hosting the load balancer worker. But I can't imagine it should be that easy. What do I need to do to distribute the Tomcat load to the extra three machines? Thanks. Update: The current configuration is using a workers2.properties configuration file. From all of the documentation online I have not been able to determine the distinction between the workers.properties and the workers2.properties. Most of the examples that I have found are configuring the workers.properties and revolve around adding workers and registering them in the worker.list element. The workers2.properties does not appears to have a worker.list element and the syntax is different enough between the workers.properties and the workers2.properties that I'm doubtful that I can add that element. If I just add my multiple AJP workers to the workers2.properties file do I need to worry about the apparent lack of a worker.list element? [ajp13:localhost:8009] channel=channel.socket:localhost:8009 group=lb [ajp13:host2.mydomain.local:8009] channel=channel.socket:host2.mydomain.local:8009 group=lb [ajp13:host3.mydomain.local:8009] channel=channel.socket:host3.mydomain.local:8009 group=lb A couple of side notes... One I've noticed that sometime Tomcat doesn't seem to reload my changes and I don't know why. Also, I have no idea why this configuration has a workers2.properties and not a workers.properties. I've been assuming that it's based on version but I haven't seen anything to back up that assumption.

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  • How can we find second maximum from array efficiently?

    - by Xinus
    Is it possible to find the second maximum number from an array of integers by traversing the array only once? As an example, I have a array of five integers from which I want to find second maximum number. Here is an attempt I gave in the interview: #define MIN -1 int main() { int max=MIN,second_max=MIN; int arr[6]={0,1,2,3,4,5}; for(int i=0;i<5;i++){ cout<<"::"<<arr[i]; } for(int i=0;i<5;i++){ if(arr[i]>max){ second_max=max; max=arr[i]; } } cout<<endl<<"Second Max:"<<second_max; int i; cin>>i; return 0; } The interviewer, however, came up with the test case int arr[6]={5,4,3,2,1,0};, which prevents it from going to the if condition the second time. I said to the interviewer that the only way would be to parse the array two times (two for loops). Does anybody have a better solution?

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  • Operator+ for a subtype of a template class.

    - by baol
    I have a template class that defines a subtype. I'm trying to define the binary operator+ as a template function, but the compiler cannot resolve the template version of the operator+. #include <iostream> template<typename other_type> struct c { c(other_type v) : cs(v) {} struct subtype { subtype(other_type v) : val(v) {} other_type val; } cs; }; template<typename other_type> typename c<other_type>::subtype operator+(const typename c<other_type>::subtype& left, const typename c<other_type>::subtype& right) { return typename c<other_type>::subtype(left.val + right.val); } // This one works // c<int>::subtype operator+(const c<int>::subtype& left, // const c<int>::subtype& right) // { return c<int>::subtype(left.val + right.val); } int main() { c<int> c1 = 1; c<int> c2 = 2; c<int>::subtype cs3 = c1.cs + c2.cs; std::cerr << cs3.val << std::endl; } I think the reason is because the compiler (g++4.3) cannot guess the template type so it's searching for operator+<int> instead of operator+. What's the reason for that? What elegant solution can you suggest?

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  • How to enforce that HTTP client uses conditional requests for updates?

    - by Day
    In a (proper RMM level 3) RESTful HTTP API, I want to enforce the fact that clients should make conditional requests when updating resources, in order to avoid the lost update problem. What would be an appropriate response to return to clients that incorrectly attempt unconditional PUT requests? I note that the (abandoned?) mod_atom returns a 405 Method Not Allowed with an Allow header set to GET, HEAD (view source) when an unconditional update is attempted. This seems slightly misleading - to me this implies that PUT is never a valid method to attempt on the resource. Perhaps the response just needs to have an entity body explaining that If-Match or If-Unmodified-Since must be used to make the PUT request conditional in which case it would be allowed? Or perhaps a 400 Bad Request with a suitable explanation in the entity body would be a better solution? But again, this doesn't feel quite right because it's using a 400 response for a violation of application specific semantics when RFC 2616 says (my emphasis): The request could not be understood by the server due to malformed syntax. But than again, I think that using 400 Bad Request for application specific semantics is becoming a widely accepted pragmatic solution (citation needed!), and I'm just being overly pedantic.

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  • Google maps api Directions User defined Steps

    - by Via Lactea
    Hi All, I have a google map service with the stores mapped on it. I also have directions service (then you define two addresses or more and it shows you a way on this map, see google map api directions). So I wa?? to show the nearest stores to this way. Of course it could be the store located in the next streat of my way, so it also should be included to the list. So far I just found only an array of steps in the directions object which I get from google maps api. But these steps are predefined by google, so they can be too close one each to other and they also can be too far (if a part of your route is a highway or there is no any special steps on your way etc.) So, what I want to do. I want to make my own steps on the line that I get from google directions (for example to put these steps on my line every 500 meeters etc.), and after that to search every step for any stores around 200 meeters. Is it possible to do? I cannot find any solution of this idea in internet.

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  • Java / Spring MVC 3 validation of an email address

    - by Tim
    I have a Java backend with Spring MVC and I am using validation in this way on my domain object for an email address: import javax.validation.constraints.NotNull; import javax.validation.constraints.Pattern; import javax.validation.constraints.Size; ... @NotNull @Size(min = 1, max = 100) @Pattern(regexp="^([a-zA-Z0-9\\-\\.\\_]+)'+'(\\@)([a-zA-Z0-9\\-\\.]+)'+'(\\.)([a-zA-Z]{2,4})$") private String email; But all I get with these lines of code Set<ConstraintViolation<Person>> failures = validator.validate(personObject); ... Map<String, String> failureMessages = new HashMap<String, String>(); for (ConstraintViolation<Person> failure : failures) { failureMessages.put(failure.getPropertyPath().toString(), failure.getMessage()); System.out.println(failure.getPropertyPath().toString()+" - "+failure.getMessage()) } I get this on the console: email - must match "^([a-zA-Z0-9\\-\\.\\_]+)'+'(\\@)([a-zA-Z0-9\\-\\.]+)'+'(\\.)([a-zA-Z]{2,4})$" but I have as email address [email protected], so the regexp does not match. So I have two prolems: What's wrong here? And how can I define a error message on my own, because display this to the user, that is not a good thing :-) Thank you in advance for your help and Best Regards.

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  • Setting pixel values in Nvidia NPP ImageCPU objects?

    - by solvingPuzzles
    In the Nvidia Performance Primitives (NPP) image processing examples in the CUDA SDK distribution, images are typically stored on the CPU as ImageCPU objects, and images are stored on the GPU as ImageNPP objects. boxFilterNPP.cpp is an example from the CUDA SDK that uses these ImageCPU and ImageNPP objects. When using a filter (convolution) function like nppiFilter, it makes sense to define a filter as an ImageCPU object. However, I see no clear way setting the values of an ImageCPU object. npp::ImageCPU_32f_C1 hostKernel(3,3); //allocate space for 3x3 convolution kernel //want to set hostKernel to [-1 0 1; -1 0 1; -1 0 1] hostKernel[0][0] = -1; //this doesn't compile hostKernel(0,0) = -1; //this doesn't compile hostKernel.at(0,0) = -1; //this doesn't compile How can I manually put values into an ImageCPU object? Notes: I didn't actually use nppiFilter in the code snippet; I'm just mentioning nppiFilter as a motivating example for writing values into an ImageCPU object. The boxFilterNPP.cpp example doesn't involve writing directly to an ImageCPU object, because nppiFilterBox is a special case of nppiFilter that uses a built-in gaussian smoothing filter (probably something like [1 1 1; 1 1 1; 1 1 1]).

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  • Is there a way to make sure classes implementing an Interface implement static methods?

    - by Tobias Kienzler
    Frist of all, I read erickson's usefull reply to "Why can’t I define a static method in a Java interface?". This question is not about the "why" but about the "how then?". So basically I want one Interface to provide both usual methods and e.g. a getSimilarObject method. For (a made up) example public interface ParametricFunction { /** @return f(x) using the parameters */ static abstract public double getValue(double x, double[] parameters); /** @return The function's name */ static abstract public String getName(); } and then public class Parabola implements ParametricFunction { /** @return f(x) = parameters[0] * x² + parameters[1] * x + parameters[2] */ static public double getValue(double x, double[] parameters) { return ( parameters[2] + x*(parameters[1] + x*parameters[0])); } static public String getName() { return "Parabola"; } } Since this is not allowed in the current Java standard, what is the closest thing to this? The idea behind this is putting several ParametricFunction's in a package and use Reflection to list them all, allowing the user to pick e.g. which one to plot. Obviously one could provide a loader class containing an array of the available ParametricFunction's, but every time a new one is implemented one has to remember adding it there, too.

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  • Plugin architecture in C using libdl

    - by LukeN
    I've been toying around, writing a small IRC framework in C that I'm now going to expand with some core functionality - but beyond that, I'd like it to be extensible with plugins! Up until now, whenever I wrote something IRC related (and I wrote a lot, in about 6 different languages now... I'm on fire!) and actually went ahead to implement a plugin architecture, it was inside an interpreted language that had facilities for doing (read: abusing) so, like jamming a whole script file trough eval in Ruby (bad!). Now I want to abuse something in C! Basically there's three things I could do define a simple script language inside of my program use an existing one, embedding an interpreter use libdl to load *.so modules on runtime I'm fond of the third one and raather avoid the other two options if possible. Maybe I'm a masochist of some sort, but I think it could be both fun and useful for learning purposes. Logically thinking, the obvious "pain-chain" would be (lowest to highest) 2 - 1 - 3, for the simple reason that libdl is dealing with raw code that can (and will) explode in my face more often than not. So this question goes out to you, fellow users of stackoverflow, do you think libdl is up to this task, or even a realistic thought?

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  • Is the 'var' keyword bad? Or am I just old school?

    - by WaggingSiberian
    Recently I overheard junior developer ask "why do you use 'var' so much?". The mid-level developer responded "I use VAR all the time. I love it! I don't have to figure out the type." I didn't have the time or energy to get into a religious war and hey, I'm still the new guy here :-) I understand var has its place. LINQ comes to mind. But I have also always been told the use of var represents lazy programming and I should just use the correct type to begin with. If it's an int, define it as an int, not a var. When reviewing code, seeing the type makes it easier to follow. My opinion is, it's just lazy but there are exceptions. Var also reminds me of the VB/VBA variant type. It also had its place. I recall (from many years ago) its usage being less-than-desirable type and it was rather resource hungry. Am I just being stuck in my ways? Should we start using var all the time as my co-worker does?

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