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  • Is it possible to implement events in C++?

    - by acidzombie24
    I wanted to implement a C# event in C++ just to see if i could do it. I got stuck, i know the bottom is wrong but what i realize my biggest problem is... How do i overload the () operator to be whatever is in T in this case int func(float)? I cant? can i? Can i implement a good alternative? #include <deque> using namespace std; typedef int(*MyFunc)(float); template<class T> class MyEvent { deque<T> ls; public: MyEvent& operator +=(T t) { ls.push_back(t); return *this; } }; static int test(float f){return (int)f; } int main(){ MyEvent<MyFunc> e; e += test; }

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  • What am I doing wrong with SVN merging?

    - by randomusername
    When SVN with merge tracking works, it's really nice, I love it. But it keeps getting twisted up. We are using TortoiseSVN. We continuously get the following message: Error: Reintegrate can only be used if revisions 1234 through 2345 were previously merged from /Trunk to the reintegrate source, but this is not the case For reference, this is the method we are using: Create a Branch Develop in the branch Occasionally Merge a range of revisions from the Trunk to the Branch When branch is stable, Reintegrate a branch from the branch to the trunk Delete the branch I Merge a range of revisions from the trunk to the branch (leaving the range blank, so it should be all revisions) just prior to the reintegrate operation, so the branch should be properly synced with the trunk. Right now, the Trunk has multiple SVN merge tracking properties associated with it. Should it? Or should a Reintegrate not add any merge tracking info? Is there something wrong with our process? This is making SVN unusable - 1 out of every 3 reintegrates forces me to dive in and hack at the merge tracking info.

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  • SVG text - total length changes depending on zoom

    - by skco
    In SVG (for web-browsers), if i add a <text>-element and add some text to it the total rendered width of the text string will change depending on the scale of the text. Lets say i add "mmmmmmmmmmmmmmmmmmmmmmmmmmA" as text, then i want to draw a vertical line(or other exactly positioned element) intersecting the very last character. Works fine but if i zoom out the text will become shorter or longer and the line will not intersect the text in the right place anymore. The error can be as much as +/- 5 characters width which is unacceptable. The error is also unpredictable, 150% and 160% zoom can add 3 characters length while 155% is 2 charlengths shorter. My zoom is implemented as a scale-transform on the root element of my canvas which is a <g>. I have tried to multiply the font-size with 1000x and scale down equally on the zoom-transform and vice versa in case it was a floating point error but the result is the same. I found the textLength-attribute[1] which is supposed to adjust the total length so the text always end where i choose but it only works in Webkit. Firefox and Opera seems to not care at all about this value (haven't tried in IE9 yet). Is there any way to render text exactly positioned without resorting to homemade filling of font-outlines? [1] http://www.w3.org/TR/SVG11/text.html#TextElementTextLengthAttribute Update Snippet of the structure i'm using <svg> <g transform="scale(1)"> <!--This is the root, i'm changing the scale of this element to zoom --> <g transform="scale(0.014)"> <!--This is a wrapper for multi-line text, scaling, other grouping etc --> <text font-size="1000" textLength="40000">ABDCDEFGHIJKLMNOPQRSTUVXYZÅÄÖabcdefghijklmnopqrstxyzåäö1234567890</text> </g> </g>

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  • Selenium : Handling Loading screens obscuring the web elements. (Java)

    - by Sheldon Cooper
    I'm writing an automated test case for a web page. Here's my scenario. I have to click and type on various web elements in an html form. But, sometimes while typing on a text field, an ajax loading image appears , fogging all elements i want to interact with. So, I'm using web-driver wait before clicking on the actual elements like below, WebdriverWait innerwait=new WebDriverWait(driver,30); innerwait.until(ExpectedConditions.elementToBeClickable(By.xpath(fieldID))); driver.findelement(By.xpath(fieldID)).click(); But the wait function returns the element even if it is fogged by another image and is not clickable. But the click() throws an exception as Element is not clickable at point (586.5, 278). Other element would receive the click: <div>Loading image</div> Do I have to check every time if the loading image appeared before interacting with any elements?.(I can't predict when the loading image will appear and fog all elements.) Is there any efficient way to handle this? Currently I'm using the following function to wait till the loading image disappears, public void wait_for_ajax_loading() throws Exception { try{ Thread.sleep(2000); if(selenium.isElementPresent("id=loadingPanel")) while(selenium.isElementPresent("id=loadingPanel")&&selenium.isVisible("id=loadingPanel"))//wait till the loading screen disappears { Thread.sleep(2000); System.out.println("Loading...."); }} catch(Exception e){ Logger.logPrint("Exception in wait_for_ajax_loading() "+e); Logger.failedReport(report, e); driver.quit(); System.exit(0); } } But I don't know exactly when to call the above function, calling it at a wrong time will fail. Is there any efficient way to check if an element is actually clickable? or the loading image is present? Thanks..

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  • License For (Mostly) Open Source Website / Service

    - by Ryan Sullivan
    I have an interesting setup and am not sure how to license a website. I know this is not legal advice, and I am not asking for any. There are so many different Open Source Licenses and I do not have the time to read every last one to see which best fits my situation. Really, I am looking for suggestions and a nudge in the right direction. My setup is: I give away for free version of my web service with a clean website interface. The implementation I use in the actual web site is (almost) identical to what I give away. The main service works the exactly the same way, but the website interface to manage features in the service is fairly different. Really the web interfaces have the same exact backend, and the front ends accomplish the same tasks, but the service I offer on my site is very rich and uses a good deal of javascript, where I kept the interface in the version I give away as simple and javascript-less as possible. Mostly so it is easy to understand and integrate into other sites. I am not entirely sure how I should license this. It is more like I develop an open source service but have a separate site built upon it. I like the GPLv3 but I am not sure if I can use it in this case especially since I am making some money off of google ad's on the site and plan on using amazon affiliates as well. Any help would be greatly appreciated. I do want to open it up as much as possible. But I still want to be able to continue with my own implementation. Thanks in advance for any information or help anyone can provide.

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  • SYN receives RST,ACK very frequently

    - by user1289508
    Hi Socket Programming experts, I am writing a proxy server on Linux for SQL Database server running on Windows. The proxy is coded using bsd sockets and in C, and it is working just fine. When I use a database client (written in JAVA, and running on a Linux box) to fire queries (with a concurrency of 100 or more) directly to the Database server, not experiencing connection resets. But through my proxy I am experiencing many connection resets. Digging deeper I came to know that connection from 'DB client' to 'Proxy' always succeeds but when the 'Proxy' tries to connect to the DB server the connection fails, due to the SYN packet getting RST,ACK. That was to give some background. The question is : Why does sometimes SYN receives RST,ACK? 'DB client(linux)' to 'Server(windows)' ---- Works fine 'DB client(linux) to 'Proxy(Linux)' to 'Server(windows)' ----- problematic I am aware that this can happen in "connection refused" case but this definitely is not that one. SYN flooding might be another scenario, but that does not explain fine behavior while firing to Server directly. I am suspecting some socket option setting may be required, that the client does before connecting and my proxy does not. Please put some light on this. Any help (links or pointers) is most appreciated. Additional info: Wrote a C client that does concurrent connections, which takes concurrency as an argument. Here are my observations: - At 5000 concurrency and above, some connects failed with 'connection refused'. - Below 2000, it works fine. But the actual problem is observed even at a concurrency of 100 or more. Note: The problem is time dependent sometimes it never comes at all and sometimes it is very frequent and DB client (directly to server) works fine at all times .

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  • Why is function's length information of other shared lib in ELF?

    - by minastaros
    Our project (C++, Linux, gcc, PowerPC) consists of several shared libraries. When releasing a new version of the package, only those libs should change whose source code was actually affected. With "change" I mean absolute binary identity (the checksum over the file is compared. Different checksum - different version according to the policy). (I should mention that the whole project is always built at once, no matter if any code has changed or not per library). Usually this can by achieved by hiding private parts of the included Header files and not changing the public ones. However, there was a case where just a delete was added to the destructor of a class TableManager (in the TableManager.cpp file!) of library libTableManager.so, and yet the binary/checksum of library libB.so (which uses class TableManager ) has changed. TableManager.h: class TableManager { public: TableManager(); ~TableManager(); private: int* myPtr; } TableManager.cpp: TableManager::~TableManager() { doSomeCleanup(); delete myPtr; // this delete has been added } By inspecting libB.so with readelf --all libB.so, looking at the .dynsym section, it turned out that the length of all functions, even the dynamically used ones from other libraries, are stored in libB! It looks like this (length is the 668 in the 3rd column): 527: 00000000 668 FUNC GLOBAL DEFAULT UND _ZN12TableManagerD1Ev So my questions are: Why is the length of a function actually stored in the client lib? Wouldn't a start address be sufficient? Can this be suppressed somehow when compiling/linking of libB.so (kind of "stripping")? We would really like to reduce this degree of dependency...

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  • What does the destructor do silently?

    - by zhanwu
    Considering the following code which looks like that the destructor doesn't do any real job, valgrind showed me clearly that it has memory leak without using the destructor. Any body can explain me what does the destructor do in this case? #include <iostream> using namespace std; class A { private: int value; A* follower; public: A(int); ~A(); void insert(int); }; A::A(int n) { value = n; follower = NULL; } A::~A() { if (follower != NULL) delete follower; cout << "do nothing!" << endl; } void A::insert(int n) { if (this->follower == NULL) { A* f = new A(n); this->follower = f; } else this->follower->insert(n); } int main(int argc, char* argv[]) { A* objectA = new A(1); int i; for (i = 0; i < 10; i++) objectA->insert(i); delete objectA; }

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  • Better way to catch trouble points

    - by mac
    User submits a CSV file which is consumed by a program. Values which are used throughout the program come from the CSV, natually if values are missed it is a problem. Below is my solution. Ip on top private List<String> currentFieldName = new ArrayList<String>(); As part of the method: try { setCurrentFieldName("Trim Space"); p.setTrimSpace(currentLineArray[dc.getTRIM_POSITION()].equals("yes") ? true : false); setCurrentFieldName("Ignore Case"); p.setIgnoreCase(currentLineArray[dc.getIGNORE_CASE_POSITION()].equals("yes") ? true : false); } catch (NullPointerException e) { throw new InputSpreadsheetValueUnassignedException("\"Type\" field not set: " + currentFieldName); } And the method which keeps track of a current field being looked at: private void setCurrentFieldName(String fieldName) { currentFieldName.clear(); currentFieldName.add(fieldName); } The idea there is that if user fails to submit value and i will end up getting null, before throwing an exception, i will know what value was not assigned. So, this being said, specific questions: Is what i have shown below an acceptable solution? Can you suggest something more elegant?

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  • Class lookup structure array in C++

    - by wyatt
    I'm trying to create a structure array which links input strings to classes as follows: struct {string command; CommandPath cPath;} cPathLookup[] = { {"set an alarm", AlarmCommandPath}, {"send an email", EmailCommandPath}, {"", NULL} }; which will be used as follows: CommandPath *cPath = NULL; string input; getline(cin, input); for(int i = 0; cPathLookup[i] != ""; i++) { if(cPathLookup[i].command == input) cPath = new cPathLookup[i].cPath; } Obviously, this code is meaningless, but I think my intention is apparent - depending on input, I'd like cPath to be initialized as either a new AlarmCommandPath or a new EmailCommandPath. I could handle it with a function returning an instance depending on input, but a whole sequence of ifs just seems inelegant. I should also note that, in case it's not apparent and important, that AlarmCommandPath and EmailCommandPath are derived from CommandPath, and CommandPath is an abstract class. Thanks for any help you can offer. EDIT: I just noticed that, in spite of CommandPath being abstract, I have a declaration: CommandPath *cPath = NULL; in working code. Why does that compile?

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  • Query syntax error selecting from 3 tables

    - by Toni Michel Caubet
    Given info about an object: id, user_id, group_id Given info about an user: id_user, id_loc I need to get i one query: The name of the user (in table users) The name of the location of the user (in table locs) The name of the group of the object (in table groups) I am trying like this: SELECT usuarios.first_name as username, usuarios.id as userid, usuarios.avatar as useravatar, usuarios.id_loc, locs.name as locname, groups.name as groupname FROM usuarios,groups,locs WHRE usuarios.id_loc = locs.id AND usuarios.id = 1 AND group.id = LIMIT 1 having an error saying You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND locs.id = 3 LIMIT 1' at line 3 What am i doing wrong? can i do this in one query? -EDIT- This is the query generator code (php+mysql): $query_loc_group_user = 'SELECT usuarios.first_name as username, usuarios.id as userid, usuarios.avatar as useravatar, usuarios.id_loc, locs.name as locname, groups.name as groupname FROM usuarios,groups,locs WHRE usuarios.id_loc = locs.id AND usuarios.id = '.$this->id_user.' AND group.id = '.$this->id_group.' LIMIT 1'; In case it helps, i am trying to do in one query this function get_info(){ $info; $result = cache_query('SELECT first_name,last_name,avatar FROM usuarios WHERE id = '.$this->id_user); foreach($result as $extra){ $info['username'] = $extra['first_name'].' '.$extra['last_name']; $info['avatar'] = $extra['avatar']; } $result1 = cache_query('SELECT name FROM locs WHERE id = '.$this->id_user); foreach($result1 as $extra){ $info['locname'] = $extra['name']; } $result2 = cache_query('SELECT name FROM locs WHERE id = '.$this->id_user); foreach($result2 as $extra){ $info['groupname'] = $extra['name']; } return $info; }

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  • PHP shell_exec() - Run directly, or perform a cron (bash/php) and include MySQL layer?

    - by Jimbo
    Sorry if the title is vague - I wasn't quite sure how to word it! What I'm Doing I'm running a Linux command to output data into a variable, parse the data, and output it as an array. Array values will be displayed on a page using PHP, and this PHP page output is requested via AJAX every 10 seconds so, in effect, the data will be retrieved and displayed/updated every 10 seconds. There could be as many as 10,000 characters being parsed on every request, although this is usually much lower. Alternative Idea I want to know if there is a better* alternative method of retrieving this data every 10 seconds, as multiple users (<10) will be having this command executed automatically for them. A cronjob running on the server could execute either bash or php (which is faster?) to grab the data and store it in a MySQL database. Then, any AJAX calls to the PHP output would return values in the MySQL database rather than making a direct call to execute server code every 10 seconds. Why? I know there are security concerns with running execs directly from PHP, and (I hope this isn't micro-optimisation) I'm worried about CPU usage on the server. The server is running a sempron processor. Yes, they do still exist. Having this only execute when the user is on the page (idea #1) means that the server isn't running code that doesn't need to be run. However, is this slow and insecure? Just in case the type of linux command may be of assistance in determining it's efficiency: shell_exec("transmission-remote $host:$port --auth $username:$password -l"); I'm hoping that there are differences in efficiency and level of security with the two methods I have outlined above, and that this isn't just micro-micro-optimisation. If there are alternative methods that are better*, I'd love to learn about these! :)

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  • CSS to Make 2 Column Content Areas

    - by Joe Majewski
    I'm trying to stray away from using tables to form the layout of my content, and I can think of two alternatives that I'd like to better learn: (1) styling list items to be side-by-side, and (2) using div blocks that float onto the same line. Both of these would have their own uses for what I'm working on. I'm already using div tags to form the entire layout of my three-column template, but what I need to do now is a bit different. In case it helps, my project can be found here. In short, here's my question; how would I style a div so that the width of it is 50% of the width of the area it occupies, rather than 50% of the width of the page? As for my other question, what would be the best approach to styling list items so that they are side-by-side? I'm working on a registration script now, and instead of using a table with "Username" on the left and the input text on the right, I can use two list items. It's late and I've been working on this project of mine for about 8 hours straight now, so I apologize if I'm asking anything confusing. Feel free to ask me any questions about what I'm trying to do. Thanks, friends. :)

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  • Getting a stream back from a .Net remoting service that is accessible with IP v4 and v6

    - by jon.ediger
    My company has an existing .Net Remoting service that listens on a port, fronting interfaces used by external systems. This all works great with IP v4 based communications. However, this service now needs to support both IP v4 communications and IP v6 communications. I have found info that the system.runtime.remoting section of the app.config should include two channels as follows: <channel ref="tcp" name="tcp6" port="9000" bindTo="[::]" /> <channel ref="tcp" name="tcp4" port="9000" bindTo="0.0.0.0" /> The above config file changes to the System.Runtime.Remoting config section will get the remoting service responding to non-stream functions on both ip v4 and ip v6. The issue comes only when attempting to get a stream back, used to upload or download large files. In this case, instead of getting a usable stream back, the following ArgumentException is thrown instead: IPv4 address 0.0.0.0 and IPv6 address ::0 are unspecified addresses that cannot be used as a target address. Parameter name: hostNameOrAddress Is there a way to modify the app.config (in the system.runtime.remoting section, or another section) so that the service will return a stream mapped to a real ip so the client can actually upload/download files while maintaining the ability to use both IP v4 and IP v6?

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  • syntax for MySQL INSERT with an array of columns

    - by Mike_Laird
    I'm new to PHP and MySQL query construction. I have a processor for a large form. A few fields are required, most fields are user optional. In my case, the HTML ids and the MySQL column names are identical. I've found tutorials about using arrays to convert $_POST into the fields and values for INSERT INTO, but I can't get them working - after many hours. I've stepped back to make a very simple INSERT using arrays and variables, but I'm still stumped. The following line works and INSERTs 5 items into a database with over 100 columns. The first 4 items are strings, the 5th item, monthlyRental is an integer. $query = "INSERT INTO `$table` (country, stateProvince, city3, city3Geocode, monthlyRental) VALUES ( '$country', '$stateProvince', '$city3', '$city3Geocode', '$monthlyRental')"; When I make an array for the fields and use it, as follows: $colsx = array('country,', 'stateProvince,', 'city3,', 'city3Geocode,', 'monthlyRental'); $query = "INSERT INTO `$table` ('$colsx') VALUES ( '$country', '$stateProvince', '$city3', '$city3Geocode', '$monthlyRental')"; I get a MySQL error - check the manual that corresponds to your MySQL server version for the right syntax to use near ''Array') VALUES ( 'US', 'New York', 'Fairport, Monroe County, New York', '(43.09)' at line 1. I get this error whether the array items have commas inside the single quotes or not. I've done a lot of reading and tried many combinations and I can't get it. I want to see the proper syntax on a small scale before I go back to foreach expressions to process $_POST and both the fields and values are arrays. And yes, I know I should use mysql_real_escape_string, but that is an easy later step in the foreach. Lastly, some clues about the syntax for an array of values would be helpful, particularly if it is different from the fields array. I know I need to add a null as the first array item to trigger the MySQL autoincrement id. What else? I'm pretty new, so please be specific.

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  • Very Urgent :How to start a new session if a user click on the new tab in IE or mozilla on websphere

    - by ha22109
    Hi, I have one "user search" portlet on the home page of one application running on websphere portal server.Which display the matching user records as per the search criteria filled in the search form.I have requirement to have a "back to search input" link on the results page which onclick should show the filled form on the input jsp. The issue which i am facing is if i open the application in two diff tab of same IE browser and start giving some search criteria and submit and same time search for some other input from other IE tab (in the same browser)and then go back to previous tab and click on "back to search input" link then instead of showing me the first input it will show me the imput which i entered in the next IE tab. I am setting and getting the bean(form bean) through portlet session.but in the two diff tab of same IE it will be the sae user session (and may be the same portlet session..) Please tell me solution for this. The one thing to be notice here is i can access this "user search" application even without doing login also.so it must be taking the default portlet session in this case. what wil happen once i login and then search,will it going to overwrite the portlet session and http session or howz is that?

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  • Is there a maximum number of input controls that can be used on an HTML form?

    - by Rich
    I have an ambitious requirement for an asp.net 2.0 web page that contains a table (gridview), and each row in the grid contains 6 select (dropdown) controls for data entry. The number of rows that will be displayed is dependent upon the user's search parameters, which are specified in another area of the page. Unfortunately, with the default (and even basic) search parameters specified, the grid could contain several hundred rows. I've noticed that the browser, in this case IE8, starts behaving rather erratically once I reach a large number of rows -- no documented evidence for the number of rows where this begins to be a problem. For example, trying to view the source of the page results in a message from IE stating that there was a problem with the page that forced the browser to reload it, and I never get the source. Obviously the page loads and renders rather slowly also. I know that my solution is probably going to involve paging the gridview such that it only displays 20 or so rows per page, and I'll have to write code to handle the saving of changes in the dropdown values when the user changes pages. I can probably turn off viewstate on the gridview also. However, the question I really want to pose is this -- has anyone seen a documented rule indicating the maximum number of input controls that an HTML browser form is supposed to be able to contain? I could not find anything on the Internet after doing a search, and I suspect the answer may be whatever the browser can handle based on the machine configuration it is running on. Any rules of thumb you use? Thanks for any suggestions. Rich

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  • (Python/Pyramid) Better ways to have standard list/form editors?

    - by badcat
    I'm working on a number of Pyramid (former Pylons) projects, and often I have the need to display a list of some content (let's say user accounts, log entries or simply some other data). A user should be able to paginate through the list, click on a row and get a form where he/she can edit the contents of that row. Right now I'm always re-inventing the wheel by having Mako templates which use webhelpers for the pagination, Jquery UI for providing a dialog and I craft the editor form and AJAX requests on the client and server side by hand. As you may know, this eats up painfully much time. So what I'm wondering is: Is there a better way of providing lists, editor dialog and server/client communication about this, without having to re-invent the wheel every time? I heard Django takes off a big load of that by providing user accounts and other stuff out of the box; but in my case it's not just about user accounts, it can be any kind of data that is stored on the server-side in a SQL database, which should be able to be edited by a user. Thanks in advance!

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  • Detecting TCP dropout over an unreliable network

    - by yx
    I am doing some experimentation over an unreliable radio network (home brewed) using very rudimentary java socket programming to transfer messages back and forth between the end nodes. The setup is as follows: Node A --- Relay Node --- Node B One problem I am constantly running into is that somehow the connection drops out and neither Node A or B knows that the link is dead, and yet continues to transmit data. The TCP connection does not time out either. I have added in a heartbeat message that causes a timeout after a while, but I still would like to know what is the underlying cause of why TCP does not time out. Here are the options I am enabling when setting up a socket: channel.socket().setKeepAlive(false); channel.socket().setTrafficClass(0x08); // for max throughput This behavior is strange since it is totally different than when I have a wired network. On a wired network, I can simulate a disconnected connection by pulling out the ethernet cord, however, once I plug the cord back in, the connection becomes restablished and messages begin to be passed through once more. On the radio network, the connection is never reestablished and once it silently dies, the messages never resume. Is there some other unknown java implentation or setting for a socket that I can use, also, why am I seeing this behavior in the first place? And yes, before anyone says anything, I know TCP is not the preffered choice over an unreliable network, but in this case I wanted to ensure no packet loss.

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  • Split a string by comma, quote and full-stop.. with a few exceptions

    - by dunc
    I've got a lot of text, similar to the following paragraph, which I'd like to split into words without punctuation (', ", ,, ., newline etc).. with a few exceptions. Initially considered endemic to the Chalakudy River system in Kerala state, southern India, but now recognised to have a wider distribution in surrounding drainages including the Periyar, Manimala, and Pamba river though the Manimala data may be questionable given it seems to be the type locality of P. denisonii. In the Achankovil River basin it occurs sympatrically, and sometimes syntopically, with P. denisonii. Wild stocks may have dwindled by as much as 50% in the last 15 years or so with collection for the aquarium trade largely held responsible although habitats are also being degraded by pollution from agricultural and domestic sources, plus destructive fishing methods involving explosives or organic toxins. The text refers to P. denisonii which is a species of fish. It's an abbreviation of Genus species. I would like this reference to be one word. So, for instance, this is the kind of array I'd like to see: Array ( ... [44] given [45] it [46] seems [47] to [48] be [49] the [50] type [51] locality [52] of [53] P. denisonii [54] In [55] the ... ) The only things that distinguish these species references such as P. denisonii from a new sentence like end. New are: The P (for Puntius, as in the P. in the aforementioned example) is only ever one letter, always a capital the d (as in . denisonii) is always either a lower case letter or an apostrophe (') What regexp can I use with preg_split to give me such an array? I've tried a simple explode( " ", $array ) but it doesn't do the job at all. Thanks in advance,

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  • Can a member struct be zero-init from the constructor initializer list without calling memset?

    - by selbie
    Let's say I have the following structure declaration (simple struct with no constructor). struct Foo { int x; int y; int z; char szData[DATA_SIZE]; }; Now let's say this struct is a member of a C++ class as follows: class CFoobar { Foo _foo; public: CFoobar(); }; If I declare CFoobar's constructor as follows: CFoobar::CFoobar() { printf("_foo = {%d, %d, %d}\n", _foo.x, _foo.y,_foo.z); for (int x = 0; x < 100; x++) printf("%d\n", _foo.szData[x]); } As you would expect, when CFoobar's constructor runs, garbage data gets printed out Obviously, the easy fix is to memset or ZeroMemory &_foo. It's what I've always done... However, I did notice that if add _foo to the constructor's initialization list with no parameters as follows: CFoobar::CFoobar() : _foo() { That this appears to zero-out the member variables of _foo. At least that was the case with g++ on linux. Now here's my question: Is this standard C++, or is this compiler specific behavior? If it's standard behavior, can someone quote me a reference from an official source? Any "gotchas" in regards to implicit zero-init behavior with more complicated structs and classes?

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  • Recommendation for using equals in Entities and avoiding LazyInitializationExceptions?

    - by huxendupsel
    In the beginning there is a problem that wants to be solved. In my case i got an LazyInitializationException while using indexof in a Collection to retrieve an Object for manipulation. Here i start to think about using equals in EntityBeans (OR-Mapper at all). I know there are some discussions about overriding equals in association with OR-Mapper as hibernate like [1] Entities equals(), hashCode() and toString(). How to correctly implement them? [2] To equals and hashcode or not on entity classes, that is the question. [3] Overriding equals and hashCode in Java I currently have some entities which implements the equals but inside the code i could not use equals several times because of the LazyInitializationExceptions. So i had to workaround and use eg. the name property of the object to identify it's equality. From my point of view the whole 'LazyInitializationException-thing' is not really mentioned in this questions. I'd like to know have you got some good patterns or real live recommendations how to avoid such exception in an equal-Method. Shall i use some helper Methodes to distinguish if a Object of a class is already initialized (4) or should i apdicate the use of equals and use helper classes instead (2)? And what is about catching LazyInitializationExceptions in the equals? [Edit]: If you put equals in context with the initialization of the Object then it will gain importance. Sometimes it is nessesary to have the Object fully initialized but sometimes you don't want to. Because you just need the Object itself (name, id, ...) not its Collection-Properties. So just for equalization you have to reattach the Object and load the whole bunch you don't realy need? Are there any other solutions for such a problem?

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  • remove versioning on boost xml serialization

    - by cppanda
    hi, i just can't find a way to remove the version tracking from the boost xmlarchives. example <Settings class_id="0" tracking_level="0" version="1"> <px class_id="1" tracking_level="1" version="0" object_id="_0"> <TestInt>3</TestInt> <Resolution class_id="2" tracking_level="0" version="0"> <x>800</x> <y>600</y> </Resolution> <SomeStuff>0</SomeStuff> </px> </Settings> I want to get ride of the class_id="0" tracking_level="0" version="1" stuff, because for in this case i just don't need it and want a simple clean config like file code void serialize(Archive & ar, const unsigned int version) { ar & make_nvp("TestInt", TestInt); ar & make_nvp("Resolution", resolution); ar & make_nvp("SomeStuff", SomeStuff); } i found boost::serialization::track_never, but nowhere to use it

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  • Difference between the address space of parent process and its child process in Linux?

    - by abbas1707
    Hi, I am confused about it. I have read that when a child is created by a parent process, child gets a copy of its parent's address space. What it means here by copy? If i use code below, then it prints same addresses of variable 'a' which is on heap in all cases. i.e in case of child and parent. So what is happening here? #include <sys/types.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> int main () { pid_t pid; int *a = (int *)malloc(4); printf ("heap pointer %p\n", a); pid = fork(); if (pid < 0) { fprintf (stderr, "Fork Failed"); exit(-1); } else if (pid == 0) { printf ("Child\n"); printf ("in child heap pointer %p\n", a); } else { wait (NULL); printf ("Child Complete\n"); printf ("in parent heap pointer %p\n", a); exit(0); } }

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  • How can I make PHP scripts timeout gracefully while waiting for long-running MySQL queries?

    - by Mark B
    I have a PHP site which runs quite a lot of database queries. With certain combinations of parameters, these queries can end up running for a long time, triggering an ugly timeout message. I want to replace this with a nice timeout message themed according to the rest of my site style. Anticipating the usual answers to this kind of question: "Optimise your queries so they don't run for so long" - I am logging long-running queries and optimising them, but I only know about these after a user has been affected. "Increase your PHP timeout setting (e.g. set_time_limit, max_execution_time) so that the long-running query can finish" - Sometimes the query can run for several minutes. I want to tell the user there's a problem before that (e.g. after 30 seconds). "Use register_tick_function to monitor how long scripts have been running" - This only gets executed between lines of code in my script. While the script is waiting for a response from the database, the tick function doesn't get called. In case it helps, the site is built using Drupal (with lots of customisation), and is running on a virtual dedicated Linux server on PHP 5.2 with MySQL 5.

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