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  • Call c++ function pointer from c#

    - by Sam
    Is it possible to call a c(++) static function pointer like this typedef int (*MyCppFunc)(void* SomeObject); from c#? void CallFromCSharp(MyCppFunc funcptr, IntPtr param) { funcptr(param); } I need to be able to callback from c# into some old c++ classes. C++ is managed, but the classes are not ref classes (yet). So far I got no idea how to call a c++ function pointer from c#, is it possible?

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  • C++ boost function overloaded template

    - by aaa
    I cannot figure out why this segment gives unresolved overloaded function error (gcc version 4.3.4 (Debian 4.3.4-6)): #include <algorithm> #include <boost/function.hpp> int main { typedef boost::function2<const int&, const int&, const int&> max; max m(static_cast<max>(&std::max<int>)); } can you help me, thanks

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  • c++ Function pointer inlining

    - by wb
    I know I can pass a function pointer as a template parameter and get a call to it inlined but I wondered if any compilers these days can inline an 'obvious' inline-able function like: inline static void Print() { std::cout << "Hello\n"; } .... void (*func)() = Print; func(); Under Visual Studio 2008 its clever enough to get it down to a direct call instruction so it seems a shame it can't take it a step further?

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  • Arguments to JavaScript Anonymous Function

    - by Phonethics
    for (var i = 0; i < somearray.length; i++) { myclass.foo({'arg1':somearray[i][0]}, function() { console.log(somearray[i][0]); }); } How do I pass somearray or one of its indexes into the anonymous function ? somearray is already in the global scope, but I still get somearray[i] is undefined

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  • TSQL, Rename column of a returning table in user Function

    - by user1433660
    I have defined function which returns table with 2 columns. Can I rename these columns so that resulting table would be like: Press name | Sum of pages ? CREATE FUNCTION F_3 (@press nvarchar(255)) RETURNS @table TABLE ( Press nvarchar(255), PagesSum int ) AS BEGIN INSERT @table SELECT @press, SUM(Books.Pages) FROM Books, Press WHERE Press.Name = @press AND Books.Id_Press = Press.Id GROUP BY Press.Name RETURN END GO SELECT * FROM F_3('BHV') GO I've tried to do it like Press AS 'Press name' nvarchar(255) but that won't work.

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  • Passing template into boost function

    - by Ockonal
    template <class EventType> class IEvent; class IEventable; typedef boost::function<void (IEventable&, IEvent&)> behaviorRef; What is the right way for passing template class IEvent into boost function? With this code I get: error: functional cast expression list treated as compound expression error: template argument 1 is invalid error: invalid type in declaration before ‘;’ token

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  • Function currying in Javascript

    - by kerry
    Do you catch yourself doing something like this often? 1: Ajax.request('/my/url', {'myParam': paramVal}, function() { myCallback(paramVal); }); Creating a function which calls another function asynchronously is a bad idea because the value of paramVal may change before it is called.  Enter the curry function: 1: Function.prototype.curry = function(scope) { 2: var args = []; 3: for (var i=1, len = arguments.length; i < len; ++i) { 4: args.push(arguments[i]); 5: } 6: var m = this; 7: return function() { 8: m.apply(scope, args); 9: }; 10: } This function creates a wrapper around the function and ‘locks in’ the method parameters.  The first parameter is the scope of the function call (usually this or window).  Any remaining parameters will be passed to the method call.  Using the curry method the above call changes to: 1: Ajax.request('/my/url', {'myParam': paramVal}, myCallback.curry(window,paramVal)); Remember when passing objects to the curry method that the objects members may still change.

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  • Compute if a function is pure

    - by Oni
    As per Wikipedia: In computer programming, a function may be described as pure if both these statements about the function hold: The function always evaluates the same result value given the same argument value(s). The function result value cannot depend on any hidden information or state that may change as program execution proceeds or between different executions of the program, nor can it depend on any external input from I/O devices. Evaluation of the result does not cause any semantically observable side effect or output, such as mutation of mutable objects or output to I/O devices. I am wondering if it is possible to write a function that compute if a function is pure or not. Example code in Javascript: function sum(a,b) { return a+b; } function say(x){ console.log(x); } isPure(sum) // True isPure(say) // False

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  • Why to say, my function is of IFly type rather than saying it's Airplane type

    - by Vishwas Gagrani
    Say, I have two classes: Airplane and Bird, both of them fly. Both implement the interface IFly. IFly declares a function StartFlying(). Thus both Airplane and Bird have to define the function, and use it as per their requirement. Now when I make a manual for class reference, what should I write for the function StartFlying? 1) StartFlying is a function of type IFly . 2) StartFlying is a function of type Airplane 3) StartFlying is a function of type Bird. My opinion is 2 and 3 are more informative. But what i see is that class references use the 1st one. They say what interface the function is declared in. Problem is, I really don't get any usable information from knowing StartFlying is IFly type. However, knowing that StartFlying is a function inside Airplane and Bird, is more informative, as I can decide which instance (Airplane or Bird ) to use. Any lights on this: how saying StartFlying is a function of type IFly, can help a programmer understanding how to use the function?

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  • Apple wireless mouse and keyboard doens't work

    - by drigoSkalWalker
    I paired the mouse and keyboard on ubuntu, but it seems not work. I got this error in /var/log/syslog kernel: [ 1875.935712] input: Apple Magic Mouse as /devices/pci0000:00/0000:00:12.0/usb4/4-3/4-3:1.0/bluetooth/hci0/hci0:2/input34 kernel: [ 1875.935885] evdev: no more free evdev devices kernel: [ 1875.935893] input: failed to attach handler evdev to device input34, error: -23 kernel: [ 1875.936049] magicmouse 0005:05AC:030D.0003: input,hidraw0: BLUETOOTH HID v3.06 Mouse [Apple Magic Mouse] on 00:19:5D:0F:4A:F6 kernel: [ 2334.787710] input: Apple Wireless Keyboard as /devices/pci0000:00/0000:00:12.0/usb4/4-3/4-3:1.0/bluetooth/hci0/hci0:4/input36 kernel: [ 2334.787729] evdev: no more free evdev devices kernel: [ 2334.787737] input: failed to attach handler evdev to device input36, error: -23 kernel: [ 2334.787999] generic-bluetooth 0005:05AC:0255.0005: input,hidraw1: BLUETOOTH HID v0.50 Keyboard [Apple Wireless Keyboard] on 00:19:5D:0F:4A:F6 Nothing appears in xinput --list, only the wired mouse and keyboard. How to fix that?

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  • How to create a variadic (with variable length argument list) function wrapper in JavaScript

    - by U-D13
    The intention is to build a wrapper to provide a consistent method of calling native functions with variable arity on various script hosts - so that the script could be executed in a browser as well as in the Windows Script Host or other script engines. I am aware of 3 methods of which each one has its own drawbacks. eval() method: function wrapper () { var str = ''; for (var i=0; i<arguments.lenght; i++) str += (str ?', ':'') + ',arguments['+i+']'; return eval('[native_function] ('+str+')'); } switch() method: function wrapper () { switch (arguments.lenght) { case 0: return [native_function] (arguments[0]); break; case 1: return [native_function] (arguments[0], arguments[1]); break; ... case n: return [native_function] (arguments[0], arguments[1], ... arguments[n]); } } apply() method: function wrapper () { return [native_function].apply([native_function_namespace], arguments); } What's wrong with them you ask? Well, shall we delve into all the reasons why eval() is evil? And also all the string concatenation... Not a solution to be labeled "elegant". One can never know the maximum n and thus how many cases to prepare. This also would strech the script to immense proportions and sin against the holy DRY principle. The script could get executed on older (pre- JavaScript 1.3 / ECMA-262-3) engines that don't support the apply() method. Now the question part: is there any another solution out there?

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  • Generic function pointers in C

    - by Lucas
    I have a function which takes a block of data and the size of the block and a function pointer as argument. Then it iterates over the data and performes a calculation on each element of the data block. The following is the essential outline of what I am doing: int myfunction(int* data, int size, int (*functionAsPointer)(int)){ //walking through the data and calculating something for (int n = 0; n < size; n++){ data[n] = (*function)(data[n]); } } The functions I am passing as arguments look something like this: int mycalculation(int input){ //doing some math with input //... return input; } This is working well, but now I need to pass an additional variable to my functionpointer. Something along the lines int mynewcalculation(int input, int someVariable){ //e.g. input = input * someVariable; //... return input; } Is there an elegant way to achieve this and at the same time keeping my overall design idea?

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  • Concatenate javascript to a string/parameter in a function

    - by Gerry S
    I am using kottke.org's old JAH example to return some html to a div in a webpage. The code works fine if I use static text. However I need to get the value of a field to add to the string that is getting passed as the parameter to the function. var xmlhttp=false; /*@cc_on @*/ /*@if (@_jscript_version >= 5) try { xmlhttp = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } catch (E) { xmlhttp = false; } } @end @*/ if (!xmlhttp && typeof XMLHttpRequest != 'undefined') { xmlhttp = new XMLHttpRequest(); } function getMyHTML(serverPage, objID) { var obj = document.getElementById(objID); xmlhttp.open("GET", serverPage); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { obj.innerHTML = xmlhttp.responseText; } } xmlhttp.send(null); } And on the page.... <a href="javascript://" onclick="getMyHTML('/WStepsDE?open&category="+document.getElementById('Employee').value;+"','goeshere')">Change it!</a></p> <div id ="goeshere">Hey, this text will be replaced.</div> It fails (with the help of Firebug) with the getMyHTML call where I try to get the value of Employee to include in the first parameter. The error is "Unterminated string literal". Thx in advance for your help.

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  • How do I repass a function pointer in C++

    - by fneep
    Firstly, I am very new to function pointers and their horrible syntax so play nice. I am writing a method to filter all pixels in my bitmap based on a function that I pass in. I have written the method to dereference it and call it in the pixel buffer but I also need a wrapper method in my bitmap class that takes the function pointer and passes it on. How do I do it? What is the syntax? I'm a little stumped. Here is my code with all the irrelevant bits stripped out and files combined (read all variables initialized filled etc.). struct sColour { unsigned char r, g, b, a; }; class cPixelBuffer { private: sColour* _pixels; int _width; int _height; int _buffersize; public: void FilterAll(sColour (*FilterFunc)(sColour)); }; void cPixelBuffer::FilterAll(sColour (*FilterFunc)(sColour)) { // fast fast fast hacky FAST for (int i = 0; i < _buffersize; i++) { _pixels[i] = (*FilterFunc)(_pixels[i]); } } class cBitmap { private: cPixelBuffer* _pixels; public: inline void cBitmap::Filter(sColour (*FilterFunc)(sColour)) { //HERE!! } };

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  • function pointers callbacks C

    - by robUK
    Hello, I have started to review callbacks. I found this link: http://stackoverflow.com/questions/142789/what-is-a-callback-in-c-and-how-are-they-implemented which has a good example of callback which is very similar to what we use at work. However, I have tried to get it to work, but I have many errors. #include <stdio.h> /* Is the actual function pointer? */ typedef void (*event_cb_t)(const struct event *evt, void *user_data); struct event_cb { event_cb_t cb; void *data; }; int event_cb_register(event_ct_t cb, void *user_data); static void my_event_cb(const struct event *evt, void *data) { /* do some stuff */ } int main(void) { event_cb_register(my_event_cb, &my_custom_data); struct event_cb *callback; callback->cb(event, callback->data); return 0; } I know that callback use function pointers to store an address of a function. But there is a few things that I find I don't understand. That is what is meet by "registering the callback" and "event dispatcher"? Many thanks for any advice,

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  • PHP Function parameters - problem with var not being set

    - by Marty
    So I am obviously not a very good programmer. I have written this small function: function dispAdjuggler($atts) { extract(shortcode_atts(array( 'slot' => '' ), $atts)); $adspot = ''; $adtype = ''; // Get blog # we're on global $blog_id; switch ($blog_id) { case 1: // root blog HOME page if (is_home()) { switch ($slot) { case 'top_leaderboard': $adspot = '855525'; $adtype = '608934'; break; case 'right_halfpage': $adspot = '855216'; $adtype = '855220'; break; case 'right_med-rectangle': $adspot = '858222'; $adtype = '613526'; break; default: throw new Exception("Ad slot is not defined"); break; } When I reference the function on a page like so: <?php dispAdjuggler("top_leaderboard"); ?> The switch is throwing the default exception. What am I doing wrong here? Thanks!!

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  • remove duplicated array values in a function PHP

    - by Deividas Juškevicius
    I read all topics related to this question in stackoverflow and whole internet and cant find working sollution... Each owner has his item and when someone buy his item, owner gets an confirmation email, but when in cart is few same owner items, he gets several same email letters, so I need to remove dublicated array entries. I have tried to use DISTINCT and array_uniques functions but no luck. Any advices? I have an array and function to send mail.. function email($mail_array) { foreach(array_unique($mail_array) as $field => $value) { $result = mysql_query("select email from users where $field='$value'"); $row = mysql_fetch_array($result); $maail = mysql_real_escape_string($row['email']); $email_to = "".$maail.""; // rest of mail formatting code // create email headers $headers = 'From: '.$email_from."\r\n" . 'Reply-To: '.$email_from."\r\n" . 'X-Mailer: PHP/' . phpversion(); @mail($email_to, $email_subject, $email_message, $headers); } for ($i = 0; $i < $max; $i++) { $pid = $_SESSION['cart'][$i]['productid']; $owner = get_owner($pid); $mail_array = array( 'name' => $owner ); email($mail_array) //call function to send mail }

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  • Function Returning Negative Value

    - by Geowil
    I still have not run it through enough tests however for some reason, using certain non-negative values, this function will sometimes pass back a negative value. I have done a lot of manual testing in calculator with different values but I have yet to have it display this same behavior. I was wondering if someone would take a look at see if I am missing something. float calcPop(int popRand1, int popRand2, int popRand3, float pERand, float pSRand) { return ((((((23000 * popRand1) * popRand2) * pERand) * pSRand) * popRand3) / 8); } The variables are all contain randomly generated values: popRand1: between 1 and 30 popRand2: between 10 and 30 popRand3: between 50 and 100 pSRand: between 1 and 1000 pERand: between 1.0f and 5500.0f which is then multiplied by 0.001f before being passed to the function above Edit: Alright so after following the execution a bit more closely it is not the fault of this function directly. It produces an infinitely positive float which then flips negative when I use this code later on: pPMax = (int)pPStore; pPStore is a float that holds popCalc's return. So the question now is, how do I stop the formula from doing this? Testing even with very high values in Calculator has never displayed this behavior. Is there something in how the compiler processes the order of operations that is causing this or are my values simply just going too high? If the later I could just increase the division to 16 I think.

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  • Fire Box doesnot support program based calling function

    - by manish
    on clicking any row of the following program... i am firinf on function mail file click....function just having alert message that shoes deffrent file name on the bases of clicking... *its working properly in IE .....FireBox N other browser function doesnot call on clicking on any row.. whats problem..please help me......i am writing code for your better awareness* For Each info In fsi Response.Write("<span id=" & " 'userijd'" & " onmouseup=" & "mailfileclick('" & info.Name & "')" & ";>") Response.Write("<td width=" & "16%" & " bgcolor=" & "#FFFFFF" & " style=" & "border-bottom-style:&nbsp;solid;&nbsp;border-bottom-width:&nbsp;1px" & " bordercolor=" & "#C0C0C0" & " nowrap" & ">") Response.Write("<font face=" & "Arial" & "style=" & "font-size:&nbsp;9pt" & " color=" & "#000000" & ">" & Mid(contents, InStr(contents, "Date: ") + Len("Date:"), 17) & "</font></td>") Response.Write("</span>") Next

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  • Passing functor and function pointers interchangeably using a templated method in C++

    - by metroxylon
    I currently have a templated class, with a templated method. Works great with functors, but having trouble compiling for functions. Foo.h template <typename T> class Foo { public: // Constructor, destructor, etc... template <typename Func> void bar(T x, Func f); }; template <typename T> template <typename Func> Foo::bar(T x, Func f) { /* some code here */ } Main.cpp #include "Foo.h" template <typename T> class Functor { public: Functor() {} void operator()(T x) { /* ... */ } private: /* some attributes here */ }; void Function(T x) { /* ... */ } int main() { Foo<int> foo; foo.bar(2, Functor); // No problem foo.bar(2, Function); // <unresolved overloaded function type> return 0; }

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  • Passing data to a jQuery click() function

    - by jakenoble
    Hi I have a simple span like so <span class="action removeAction">Remove</span> This span is within a table, each row has a remove span. And then I call a URL using AJAX when that span is clicked. The AJAX event needs to know the ID of the object for that row? What is the best way of getting that ID into the click function? I thought I could do something like this <span class="action removeAction" id="1">Remove</span> But an ID should not start with a number? Right? Then I thought I could do <span class="action removeAction" id="my1">Remove</span> Then just strip the 'my' part from the ID, but that just seems Yuk! Below is my click event and where my AJAX event is. <script type="text/javascript" language="text/javascript"> $(document).ready(function() { $(".removeAction").click(function() { //AJAX here that needs to know the ID } }); </script> I am sure there is a nice way of doing this? Thanks. Jake.

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  • Work with function references

    - by Ockonal
    Hello, I have another one question about functions reference. For example, I have such definition: typedef boost::function<bool (Entity &handle)> behaviorRef; std::map< std::string, ptr_vector<behaviorRef> > eventAssociation; The first question is: how to insert values into such map object? I tried: eventAssociation.insert(std::pair< std::string, ptr_vector<behaviorRef> >(eventType, ptr_vector<behaviorRef>(callback))); But the error: no matching function for call to ‘boost::ptr_vector<boost::function<bool(Entity&)> >::push_back(Entity::behaviorRef&)’ And I undersatnd it, but can't make workable code. The second question is how to call such functions? For example, I have one object of behaviorRef, how to call it with boost::bind with passing my own values?

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  • 2 dimensional arrays passed to a function in c++

    - by John Marcus
    I'm working on doing calculations in a two dimensional array but keep getting a nasty error. i call the function by : if(checkArray(array)) and try to pass it in like this: bool checkArray(double array[][10]) //or double *array[][10] to no avail the error is error: cannot convert ‘double ()[(((unsigned int)(((int)n) + -0x00000000000000001)) + 1)]’ to ‘double’ for argument ‘1’ to ‘bool checkArray(double*)’ code snippet //array declaration int n = 10; double array[n][n]; //function call to pass in array while(f != 25) { cout<<endl; cout<<endl; if(checkArray(array)) //this is the line of the error { cout<<"EXIT EXIT EXIT"<<endl; } f++; } //function declaration bool checkArray(double *array)//, double newArray[][10]) { double length = sizeof(array); for(int i = 0; i < length; i++) for(int j = 0; j < length;j++) { double temp = array[i][j]; } }

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