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  • Which are the cons of using only non-member functions and POD?

    - by Miro
    I'm creating my own game engine. I've read these articles and this question about DOD and it was written to not use member functions and classes. I also heard some criticism to this idea. I can write it using member functions or non-member functions it would be similar. So what are the benefits/cons of that approach or when the project grows, does any of these approaches give clearer and better manageable code? With POD & non-member functions I don't have to make struct members public I can still use object id outside of engine like OpenGL does with all it's stuff, so It's not about encapsulation. POD - plain old data DOD - data oriented design

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  • What are cons of usage only non-member functions and POD?

    - by Miro
    I'm creating my own game engine. I've read these articles and this question about DOD and there was written to not use member functions and classes. I also heard some criticism to this idea. I can write it using member functions or non-member functions it would be similar. So what are benefits/cons of that approach or when project grows, does any of these approaches give clearer and better manageable code? With POD & non-member functions I don't have to make struct members public I can still use object id outside of engine like OpenGL does with all it's stuff, so It's not about encapsulation. POD - plain old data DOD - data oriented design

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  • SQL Server 2008 System Functions to Monitor the Instance, Database, Files, etc.

    SQL Server provides several system meta data functions which allow users to obtain property values of different SQL Server objects and securables. Although you can also use the SQL Server catalog views or Dynamic Management Views to obtain much of this information, in some circumstances the system meta data functions simplify the process. In this tip I am going to demonstrate some of the available system meta data functions and their usage in different scenarios.

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  • Functions registered with ExternalInterface.addCallback not available in Javascript

    - by Selene
    I'm working on a Flash game that needs to call some Javascript on the page and get data back from it. Calling Javascript from Flash works. Calling the Flash functions from Javascript (often) doesn't. I'm using the Gaia framework. What happens: The swf is loaded in with SWFObject There's a button in the Flash file. On click, it uses ExternalInterface.call() to call a Javascript function. This works. The Javascript function calls a Flash function that was exposed with ExternalInterface.addCallback(). Sometimes, the Javascript produces the following error: TypeError: myFlash.testCallback is not a function. When the error happens, it affects all functions registered with addCallback(). Gaia and some of its included libraries use addCallback(), and calling those functions from Javascript also produces the TypeError. Waiting a long time before pressing the button in Flash doesn't solve the error. Having Flash re-try addCallback() periodically doesn't solve the error When the error occurs, ExternalInterface.available = true and ExternalInterface.objectID contains the correct name for the Flash embed object. When the error occurs, document.getElementById('myflashcontent') correctly returns the Flash embed object. From my Page class: public class MyPage extends AbstractPage { // declarations of stage instances and class variables // other functions override public function transitionIn():void { send_button.addEventListener(MouseEvent.MOUSE_UP, callJS); exposeCallbacks(); super.transitionIn(); } private function exposeCallbacks():void { trace("exposeCallbacks()"); if (ExternalInterface.available) { trace("ExternalInterface.objectID: " + ExternalInterface.objectID); try { ExternalInterface.addCallback("testCallback", simpleTestCallback); trace("called ExternalInterface.addCallback"); } catch (error:SecurityError) { trace("A SecurityError occurred: " + error.message + "\n"); } catch (error:Error) { trace("An Error occurred: " + error.message + "\n"); } } else { trace("exposeCallbacks() - ExternalInterface not available"); } } private function simpleTestCallback(str:String):void { trace("simpleTestCallback(str=\"" + str + "\")"); } private function callJS(e:Event):void { if (ExternalInterface.available) { ExternalInterface.call("sendTest", "name", "url"); } else { trace("callJS() - ExternalInterface not available"); } } } My Javascript: function sendTest(text, url) { var myFlash = document.getElementById("myflashcontent"); var callbackStatus = ""; callbackStatus += '\nmyFlash[testCallback]: ' + myFlash['testCallback']; //console.log(callbackStatus); var errors = false; try { myFlash.testCallback("test string"); } catch (err) { alert("Error: " + err.toString()); error = true; } if (!error) { alert("Success"); } } var params = { quality: "high", scale: "noscale", wmode: "transparent", allowscriptaccess: "always", bgcolor: "#000000" }; var flashVars = { siteXML: "xml/site.xml" }; var attributes = { id: "myflashcontent", name: "myflashcontent" }; // load the flash movie. swfobject.embedSWF("http://myurl.com/main.swf?v2", "myflashcontent", "728", "676", "10.0.0", serverRoot + "expressInstall.swf", flashVars, params, attributes, function(returnObj) { console.log('Returned ' + returnObj.success); if (returnObj.success) { returnObj.ref.focus(); } });

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  • GCC error with variadic templates: "Sorry, unimplemented: cannot expand 'Identifier...' into a fixe

    - by Dennis
    While doing variadic template programming in C++0x on GCC, once in a while I get an error that says "Sorry, unimplemented: cannot expand 'Identifier...' into a fixed-length arugment list." If I remove the "..." in the code then I get a different error: "error: parameter packs not expanded with '...'". So if I have the "..." in, GCC calls that an error, and if I take the "..." out, GCC calls that an error too. The only way I have been able to deal with this is to completely rewrite the template metaprogram from scratch using a different approach, and (with luck) I eventually come up with code that doesn't cause the error. But I would really like to know what I was doing wrong. Despite Googling for it and despite much experimentation, I can't pin down what it is that I'm doing differently between variadic template code that does produce this error, and code that does not have the error. The wording of the error message seems to imply that the code should work according the C++0x standard, but that GCC doesn't support it yet. Or perhaps it is a compiler bug? Here's some code that produces the error. Note: I don't need you to write a correct implementation for me, but rather just to point out what is about my code that is causing this specific error // Used as a container for a set of types. template <typename... Types> struct TypePack { // Given a TypePack<T1, T2, T3> and T=T4, returns TypePack<T1, T2, T3, T4> template <typename T> struct Add { typedef TypePack<Types..., T> type; }; }; // Takes the set (First, Others...) and, while N > 0, adds (First) to TPack. // TPack is a TypePack containing between 0 and N-1 types. template <int N, typename TPack, typename First, typename... Others> struct TypePackFirstN { // sorry, unimplemented: cannot expand ‘Others ...’ into a fixed-length argument list typedef typename TypePackFirstN<N-1, typename TPack::template Add<First>::type, Others...>::type type; }; // The stop condition for TypePackFirstN: when N is 0, return the TypePack that has been built up. template <typename TPack, typename... Others> struct TypePackFirstN<0, TPack, Others...> //sorry, unimplemented: cannot expand ‘Others ...’ into a fixed-length argument list { typedef TPack type; }; EDIT: I've noticed that while a partial template instantiation that looks like does incur the error: template <typename... T> struct SomeStruct<1, 2, 3, T...> {}; Rewriting it as this does not produce an error: template <typename... T> struct SomeStruct<1, 2, 3, TypePack<T...>> {}; It seems that you can declare parameters to partial specializations to be variadic; i.e. this line is OK: template <typename... T> But you cannot actually use those parameter packs in the specialization, i.e. this part is not OK: SomeStruct<1, 2, 3, T... The fact that you can make it work if you wrap the pack in some other type, i.e. like this: SomeStruct<1, 2, 3, TypePack<T...>> to me implies that the declaration of the variadic parameter to a partial template specialization was successful, and you just can't use it directly. Can anyone confirm this?

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  • sscanf wrapping function to advance string pointer in C

    - by Dusty
    I have a function that makes a series of calls to sscanf() and then, after each, updates the string pointer to point to the first character not consumed by sscanf() like so: if(sscanf(str, "%d%n", &fooInt, &length) != 1) { // error handling } str+=length; In order to clean it up and avoid duplicating this several times over, i'd like to encapsulate this into a nice utility function that looks something like the following: int newSscanf ( char ** str, const char * format, ...) { int rv; int length; char buf[MAX_LENGTH]; va_list args; strcpy(buf, format); strcat(buf, "%n"); va_start(args, format); rv = vsscanf(*str, buf, args, &length); va_end(args); *str += length; return rv; } Then I could simply the calls as below to remove the additional parameter/bookkeeping: if(newSscanf(&str, "%d", &fooInt) != 1) { // error handling } Unfortunately, I can't find a way to append the &length parameter onto the end of the arg list directly or otherwise inside newSscanf(). Is there some way to work around this, or am I just as well off handling the bookkeeping by hand at each call?

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  • Convert old NuSoap code into PHP core soap functions

    - by Enrique
    Hi I've been testing nuSoap with codeIgniter (PHP Framework) but seems nuSoap isn't prepared to work with latest php 5.3, even if I download a patched nusoap version for php 5.3 I have the following code: require_once(APPPATH.'libraries/NuSOAP/lib/nusoap'.EXT); //includes nusoap $n_params = array('CityName' => 'San Juan', 'CountryName' => 'Argentina'); $client = new nusoap_client('http://www.webservicex.net/globalweather.asmx?WSDL'); $client->setHTTPProxy("10.2.0.1",6588,"",""); $result = $client->call('GetWeather', $n_params); Can any1 help me to convert these functions into php soap functions? Including proxy function? Thanks a lot

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  • Language Design: Combining Gotos and Functions

    - by sub
    I'm designing and currently rethinking a low-level interpreted programming language with similarities to assembler. I very soon came across the functions/loops/gotos decision problem and thought that while loops like while and for would be too high-level and unfitting, gotos would be too low level, unmaintainable and generally evil again. Functions like you know them from most languages that have return values and arguments aren't fitting in the language's concept either. So I tried to figure out something between a function and a goto which is capable of Recursion Efficient loops After some thinking I came up with the idea of subroutines: They have a beginning and an end like a function They have a name but no arguments like a goto You can go into one with jump and go out of it again before its end with return (doesn't give back any result, only stops the subroutine) Handled just like normal code - Global scope like goto So I wanted to know: Is the idea above good? What are the (dis)advantages? Would there be a better combination of function and goto or even a completely new idea?

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  • C++ wrapper for posix and linux specific functions

    - by Libzajc
    Hi Do you know about any good library wrapping posix and linux functions and structures ( eg. sockets or file descriptors ) into C++ classes? For example I'm thinking about a base FileDescriptor class and some inheriting classes ( unix sockets etc ) with methods like write, read or even some syscalls ( sendfile, splice ) - all throwing exceptions instead of setting errno. Or some shared memory class etc. I can't seem to find anything like that and by now I consider writing it myself, as I often have to write a C++ app for linux and either use C functions ( painful error checking ), or wrap them myself every time.

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  • Ellipsis notation in C#?

    - by Joshua
    Where can I get info about implementing my own methods that have the ellipsis notation, e.g. static void my_printf(char* format, ...) { } Also is that called ellipsis notation or is there a fancier name?

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  • pointers to functions

    - by DevAno1
    I have two basic Cpp tasks, but still I have problems with them. First is to write functions mul1,div1,sub1,sum1, taking ints as arguments and returning ints. Then I need to create pointers ptrFun1 and ptrFun2 to functions mul1 and sum1, and print results of using them. Problem starts with defining those pointers. I thought I was doing it right, but devcpp gives me errors in compilation. #include <iostream> using namespace std; int mul1(int a,int b) { return a * b; } int div1(int a,int b) { return a / b; } int sum1(int a,int b) { return a + b; } int sub1(int a,int b) { return a - b; } int main() { int a=1; int b=5; cout << mul1(a,b) << endl; cout << div1(a,b) << endl; cout << sum1(a,b) << endl; cout << sub1(a,b) << endl; int *funPtr1(int, int); int *funPtr2(int, int); funPtr1 = sum1; funPtr2 = mul1; cout << funPtr1(a,b) << endl; cout << funPtr2(a,b) << endl; system("PAUSE"); return 0; } 38 assignment of function int* funPtr1(int, int)' 38 cannot convertint ()(int, int)' to `int*()(int, int)' in assignment Task 2 is to create array of pointers to those functions named tabFunPtr. How to do that ?

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  • PHP: variable-length argument list by reference?

    - by GetFree
    Is it possible to create a PHP function that takes a variable number of parameters all of them by reference? It doesn't help me a function that receives by reference an array of values nor a function that takes its arguments wrapped in an object because I'm working on function composition and argument binding. Don't think about call-time pass-by-reference either. That thing shouldn't even exist.

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  • Reducing Code Repetition: Calling functions with slightly different signatures

    - by Brian
    Suppose I have two functions which look like this: public static void myFunction1(int a, int b, int c, string d) { //dostuff someoneelsesfunction(c,d); //dostuff2 } public static void myFunction2(int a, int b, int c, Stream d) { //dostuff someoneelsesfunction(c,d); //dostuff2 } What would be a good way to avoid repeated dostuff? Ideas I've thought of, but don't like: I could make d an object and cast at runtype based on type, but this strikes me as not being ideal; it removes a type check which was previously happening at compile time. I could also write a private helper class that takes an object and write both signatures as public functions. I could replace dostuff and dostuff2 with delegates or function calls or something.

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  • Compiled Linq Queries with Built-in SQL functions

    - by Brandi
    I have a query that I am executing in C# that is taking way too much time: string Query = "SELECT COUNT(HISTORYID) FROM HISTORY WHERE YEAR(CREATEDATE) = YEAR(GETDATE()) "; Query += "AND MONTH(CREATEDATE) = MONTH(GETDATE()) AND DAY(CREATEDATE) = DAY(GETDATE()) AND USERID = '" + EmployeeID + "' "; Query += "AND TYPE = '5'"; I then use SqlCommand Command = new SqlCommand(Query, Connection) and SqlDataReader Reader = Command.ExecuteReader() to read in the data. This is taking over a minute to execute from C#, but is much quicker in SSMS. I see from google searching you can do something with CompiledQuery, but I'm confused whether I can still use the built in SQL functions YEAR, MONTH, DAY, and GETDATE. If anyone can show me an example of how to create and call a compiled query using the built in functions, I will be very grateful! Thanks in advance.

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  • JavaScript Metaprogramming: Reduce boilerplate of adding functions to a function queue

    - by thurn
    I'm working with animation in JavaScript, and I have a bunch of functions you can call to add things to the animation queue. Basically, all of these functions look like this: function foo(arg1, arg2) { _eventQueue.push(function() { // actual logic } } I'm wondering now if it would be possible to cut down on this boilerplate a little bit, though, so I don't need that extra "_eventQueue" line in the function body dozens of times. Would it be possible, for example, to make a helper function which takes an arbitrary function as an argument and returns a new function which is augmented to be automatically added to the event queue? The only problem is that I need to find a way to maintain access to the function's original arguments in this process, which is... complicated.

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  • Effects of the `extern` keyword on C functions

    - by Elazar Leibovich
    In C I did not notice any effect of the extern keyword used before function declaration. At first I thougth that when defining extern int f(); in a single file forces you to implement it outside of the files scope, however I found out that both extern int f(); int f() {return 0;} And extern int f() {return 0;} Compiles just fine, with no warnings from gcc. I used gcc -Wall -ansi, he wouldn't even accept // comments. Are there any effects for using extern before function definitions? Or is it just an optional keyword with no side effects for functions. In the latter case I don't understand why did the standard designers chose to litter the grammar with superfluous keywords. EDIT: to clarify, I know there's usage for extern in variables, but I'm only asking about extern in functions.

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  • Defining functions and if statement problems

    - by David Fairbairn
    I'm having a problem with two functions and an if statement. I'm being told the functions go and postcodeChange are not defined. I'm also being told flag is an unexpected identifier at if flag == 1. Any idea where I am going wrong? Thank you. function postcodeChange(){ document.getElementById("goButton").onclick = distanceCheck; } function distanceCheck(){ var distance = document.getElementById("distance").value var patt1=new RegExp("^[0-9]+(\.[0-9]{1})?$"); var out = patt1.exec(distance); if (out == null) { //distance is not a valid number document.getElementById("distanceFlag").value = 1 } else { //distance is valid number document.getElementById("distanceFlag").value = 0 } function go(){ var flag = document.getElementById("distanceFlag").value if flag == 1 { alert("Distance is not valid- enter a number with no more than one decimal point"); } else{ popSubmit('#fa Care Provider Search Go','','0'); } }

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  • Question about DBD::CSB Statement-Functions

    - by sid_com
    From the SQL::Statement::Functions documentation: Function syntax When using SQL::Statement/SQL::Parser directly to parse SQL, functions (either built-in or user-defined) may occur anywhere in a SQL statement that values, column names, table names, or predicates may occur. When using the modules through a DBD or in any other context in which the SQL is both parsed and executed, functions can occur in the same places except that they can not occur in the column selection clause of a SELECT statement that contains a FROM clause. # valid for both parsing and executing SELECT MyFunc(args); SELECT * FROM MyFunc(args); SELECT * FROM x WHERE MyFuncs(args); SELECT * FROM x WHERE y < MyFuncs(args); # valid only for parsing (won't work from a DBD) SELECT MyFunc(args) FROM x WHERE y; Reading this I would expect that the first SELECT-statement of my example shouldn't work and the second should but it is quite the contrary. #!/usr/bin/env perl use warnings; use strict; use 5.010; use DBI; open my $fh, '>', 'test.csv' or die $!; say $fh "id,name"; say $fh "1,Brown"; say $fh "2,Smith"; say $fh "7,Smith"; say $fh "8,Green"; close $fh; my $dbh = DBI->connect ( 'dbi:CSV:', undef, undef, { RaiseError => 1, f_ext => '.csv', }); my $table = 'test'; say "\nSELECT 1"; my $sth = $dbh->prepare ( "SELECT MAX( id ) FROM $table WHERE name LIKE 'Smith'" ); $sth->execute (); $sth->dump_results(); say "\nSELECT 2"; $sth = $dbh->prepare ( "SELECT * FROM $table WHERE id = MAX( id )" ); $sth->execute (); $sth->dump_results(); outputs: SELECT 1 '7' 1 rows SELECT 2 Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2893. DBD::CSV::db prepare failed: Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2894. [for Statement "SELECT * FROM test WHERE id = MAX( id )"] at ./so_3.pl line 30. DBD::CSV::db prepare failed: Unknown function 'MAX' at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 2894. [for Statement "SELECT * FROM test WHERE id = MAX( id )"] at ./so_3.pl line 30. Could someone explaine me this behavior?

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  • Refreshing metadata on user functions t-SQL

    - by luckyluke
    I am doing some T-SQL programming and I have some Views defines on my database. The data model is still changing these days and I have some table functions defined. Sometimes i deliberately use select * from MYVIEW in such a table function to return all columns. If the view changes (or table) the function crashes and I need to recompile it. I know it is in general good thing so that it prevents from hell lotta errors but still... Is there a way to write such functions so the dont' blow up in my face everytime I change something on the underlying table? Or maybe I am doing something completely wrong... Thanks for help

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