Search Results

Search found 4993 results on 200 pages for 'conversion operator'.

Page 187/200 | < Previous Page | 183 184 185 186 187 188 189 190 191 192 193 194  | Next Page >

  • VB - Convert Web Site to Web Application

    - by Dave
    Hi This is my first time doing VB :-) I've inherited a web site, which I've converted into a web application in VS2008. The conversion has worked for everything except a Gallery control. The compile error I'm getting is: Type 'Gallery' is not defined in file: gallery_oct07.aspx.designer.vb Option Strict On Option Explicit On Partial Public Class gallery_oct07 '''<summary> '''Gallery1 control. '''</summary> '''<remarks> '''Auto-generated field. '''To modify move field declaration from designer file to code-behind file. '''</remarks> Protected WithEvents Gallery1 As Global.Gallery End Class with squiggly lines under Global.Gallery. The gallery_oct07.aspx.vb is: Partial Class gallery_oct07 Inherits System.Web.UI.Page End Class Gallery.ascx is: <%@ Control Language="C#" AutoEventWireup="true" Codebehind="Gallery.ascx.cs" Inherits="WebApplication1.Gallery"%> <asp:Repeater runat="server" ID="rptGallery"> <HeaderTemplate> <ul class='<%#CssClass%>'> </HeaderTemplate> <ItemTemplate> <li><a href='<%#ImageFolder + Eval("Name") %>' class="thickbox" rel="gallery"><img src='<%#ImageFolder + "thumb/" + Eval("Name") %>' /></a></li> </ItemTemplate> <FooterTemplate> </ul></FooterTemplate> </asp:Repeater> and the code behind is: using System; using System.IO; namespace WebApplication1 { public partial class Gallery : System.Web.UI.UserControl { public string _ImageFolder; public string ImageFolder { get { return _ImageFolder; } set { _ImageFolder = value; } } private string _cssClass = "gallery"; public string CssClass { get { return _cssClass; } set { _cssClass = value; } } protected void Page_Load(object sender, EventArgs e) { DirectoryInfo dir = new DirectoryInfo(MapPath(ImageFolder)); FileInfo[] images = dir.GetFiles("*.jpg"); rptGallery.DataSource = images; rptGallery.DataBind(); } protected void Page_PreRender(object sender, EventArgs e) { } } } The feels like a namespace issue.. My project namespace is WebApplication1. Cheers!

    Read the article

  • In Ruby, how does coerce() actually work?

    - by Jian Lin
    It is said that when we have a class Point and knows how to perform point * 3 like the following: class Point def initialize(x,y) @x, @y = x, y end def *(c) Point.new(@x * c, @y * c) end end point = Point.new(1,2) p point p point * 3 Output: #<Point:0x336094 @x=1, @y=2> #<Point:0x335fa4 @x=3, @y=6> but then, 3 * point is not understood: Point can't be coerced into Fixnum (TypeError) So we need to further define an instance method coerce: class Point def coerce(something) [self, something] end end p 3 * point Output: #<Point:0x3c45a88 @x=3, @y=6> So it is said that 3 * point is the same as 3.*(point) that is, the instance method * takes an argument point and invoke on the object 3. Now, since this method * doesn't know how to multiply a point, so point.coerce(3) will be called, and get back an array: [point, 3] and then * is once again applied to it, is that true? point * 3 which is the same as point.*(3) and now, this is understood and we now have a new Point object, as performed by the instance method * of the Point class. The question is: 1) who invokes point.coerce(3) ? Is it Ruby automatically, or is it some code inside of * method of Fixnum by catching an exception? Or is it by case statement that when it doesn't know one of the known types, then call coerce? 2) Does coerce always need to return an array of 2 elements? Can it be no array? Or can it be an array of 3 elements? 3) And is the rule that, the original operator (or method) * will then be invoked on element 0, with the argument of element 1? (element 0 and element 1 are the two elements in that array returned by coerce) Who does it? Is it done by Ruby or is it done by code in Fixnum? If it is done by code in Fixnum, then it is a "convention" that everybody follows when doing a coerce? So could it be the code in * of Fixnum do something like this: if (something.typeof? ...) else if ... # other type else if ... # other type else # if it is not a type I know array = something.coerce(self) return array[0].*(array[1]) end

    Read the article

  • translating specifications into query predicates

    - by Jeroen
    I'm trying to find a nice and elegant way to query database content based on DDD "specifications". In domain driven design, a specification is used to check if some object, also known as the candidate, is compliant to a (domain specific) requirement. For example, the specification 'IsTaskDone' goes like: class IsTaskDone extends Specification<Task> { boolean isSatisfiedBy(Task candidate) { return candidate.isDone(); } } The above specification can be used for many purposes, e.g. it can be used to validate if a task has been completed, or to filter all completed tasks from a collection. However, I want to re-use this, nice, domain related specification to query on the database. Of course, the easiest solution would be to retrieve all entities of our desired type from the database, and filter that list in-memory by looping and removing non-matching entities. But clearly that would not be optimal for performance, especially when the entity count in our db increases. Proposal So my idea is to create a 'ConversionManager' that translates my specification into a persistence technique specific criteria, think of the JPA predicate class. The services looks as follows: public interface JpaSpecificationConversionManager { <T> Predicate getPredicateFor(Specification<T> specification, Root<T> root, CriteriaQuery<?> cq, CriteriaBuilder cb); JpaSpecificationConversionManager registerConverter(JpaSpecificationConverter<?, ?> converter); } By using our manager, the users can register their own conversion logic, isolating the domain related specification from persistence specific logic. To minimize the configuration of our manager, I want to use annotations on my converter classes, allowing the manager to automatically register those converters. JPA repository implementations could then use my manager, via dependency injection, to offer a find by specification method. Providing a find by specification should drastically reduce the number of methods on our repository interface. In theory, this all sounds decent, but I feel like I'm missing something critical. What do you guys think of my proposal, does it comply to the DDD way of thinking? Or is there already a framework that does something identical to what I just described?

    Read the article

  • AudioConverterConvertBuffer problem with insz error

    - by Samuel
    Hi Codegurus, I have a problem with the this function AudioConverterConvertBuffer. Basically I want to convert from this format _ streamFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked |0 ; _streamFormat.mBitsPerChannel = 16; _streamFormat.mChannelsPerFrame = 2; _streamFormat.mBytesPerPacket = 4; _streamFormat.mBytesPerFrame = 4; _streamFormat.mFramesPerPacket = 1; _streamFormat.mSampleRate = 44100; _streamFormat.mReserved = 0; to this format _streamFormatOutput.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked|0 ;//| kAudioFormatFlagIsNonInterleaved |0; _streamFormatOutput.mBitsPerChannel = 16; _streamFormatOutput.mChannelsPerFrame = 1; _streamFormatOutput.mBytesPerPacket = 2; _streamFormatOutput.mBytesPerFrame = 2; _streamFormatOutput.mFramesPerPacket = 1; _streamFormatOutput.mSampleRate = 44100; _streamFormatOutput.mReserved = 0; and what i want to do is to extract an audio channel(Left channel or right channel) from an LPCM buffer based on the input format to make it mono in the output format. Some logic code to convert is as follows This is to set the channel map for PCM output file SInt32 channelMap[1] = {0}; status = AudioConverterSetProperty(converter, kAudioConverterChannelMap, sizeof(channelMap), channelMap); and this is to convert the buffer in a while loop AudioBufferList audioBufferList; CMBlockBufferRef blockBuffer; CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampBuffer, NULL, &audioBufferList, sizeof(audioBufferList), NULL, NULL, 0, &blockBuffer); for (int y=0; y<audioBufferList.mNumberBuffers; y++) { AudioBuffer audioBuffer = audioBufferList.mBuffers[y]; //frames = audioBuffer.mData; NSLog(@"the number of channel for buffer number %d is %d",y,audioBuffer.mNumberChannels); NSLog(@"The buffer size is %d",audioBuffer.mDataByteSize); numBytesIO = audioBuffer.mDataByteSize; convertedBuf = malloc(sizeof(char)*numBytesIO); status = AudioConverterConvertBuffer(converter, audioBuffer.mDataByteSize, audioBuffer.mData, &numBytesIO, convertedBuf); char errchar[10]; NSLog(@"status audio converter convert %d",status); if (status != 0) { NSLog(@"Fail conversion"); assert(0); } NSLog(@"Bytes converted %d",numBytesIO); status = AudioFileWriteBytes(mRecordFile, YES, countByteBuf, &numBytesIO, convertedBuf); NSLog(@"status for writebyte %d, bytes written %d",status,numBytesIO); free(convertedBuf); if (numBytesIO != audioBuffer.mDataByteSize) { NSLog(@"Something wrong in writing"); assert(0); } countByteBuf = countByteBuf + numBytesIO; But the insz problem is there... so it cant convert. I would appreciate any input Thanks in advance

    Read the article

  • WPF Reusing Xaml Effectively

    - by Steve
    Hi, I've recently been working on a project using WPF to produce a diagram. In this I must show text alongside symbols that illustrate information associated with the text. To draw the symbols I initially used some png images I had produced. Within my diagram these images appeared blurry and only looked worse when zoomed in on. To improve on this I decided I would use a vector rather than a rastor image format. Below is the method I used to get the rastor image from a file path: protected Image GetSymbolImage(string symbolPath, int symbolHeight) { Image symbol = new Image(); symbol.Height = symbolHeight; BitmapImage bitmapImage = new BitmapImage(); bitmapImage.BeginInit(); bitmapImage.UriSource = new Uri(symbolPath); bitmapImage.DecodePixelHeight = symbolHeight; bitmapImage.EndInit(); symbol.Source = bitmapImage; return symbol; } Unfortunately this does not recognise vector image formats. So instead I used a method like the following, where "path" is the file path to a vector image of the format .xaml: public static Canvas LoadXamlCanvas(string path) { //if a file exists at the specified path if (File.Exists(path)) { //store the text in the file string text = File.ReadAllText(path); //produce a canvas from the text StringReader stringReader = new StringReader(text); XmlReader xmlReader = XmlReader.Create(stringReader); Canvas c = (Canvas)XamlReader.Load(xmlReader); //return the canvas return c; } return null; } This worked but drastically killed performance when called repeatedly. I found the logic necessary for text to canvas conversion (see above) was the main cause of the performance problem therefore embedding the .xaml images would not alone resolve the performance issue. I tried using this method only on the initial load of my application and storing the resulting canvases in a dictionary that could later be accessed much quicker but I later realised when using the canvases within the dictionary I would have to make copies of them. All the logic I found online associated with making copies used a XamlWriter and XamlReader which would again just introduce a performance problem. The solution I used was to copy the contents of each .xaml image into its own user control and then make use of these user controls where appropriate. This means I now display vector graphics and performance is much better. However this solution to me seems pretty clumsy. I'm new to WPF and wonder if there is some built in way of storing and reusing xaml throughout an application? Apologies for the length of this question. I thought having a record of my attempts might help someone with any similar problem. Thanks.

    Read the article

  • Using a map with set_intersection

    - by Robin Welch
    Not used set_intersection before, but I believe it will work with maps. I wrote the following example code but it doesn't give me what I'd expect: #include <map> #include <string> #include <iostream> #include <algorithm> using namespace std; struct Money { double amount; string currency; bool operator< ( const Money& rhs ) const { if ( amount != rhs.amount ) return ( amount < rhs.amount ); return ( currency < rhs.currency ); } }; int main( int argc, char* argv[] ) { Money mn[] = { { 2.32, "USD" }, { 2.76, "USD" }, { 4.30, "GBP" }, { 1.21, "GBP" }, { 1.37, "GBP" }, { 6.74, "GBP" }, { 2.55, "EUR" } }; typedef pair< int, Money > MoneyPair; typedef map< int, Money > MoneyMap; MoneyMap map1; map1.insert( MoneyPair( 1, mn[1] ) ); map1.insert( MoneyPair( 2, mn[2] ) ); map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) MoneyMap map2; map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) map1.insert( MoneyPair( 5, mn[5] ) ); map1.insert( MoneyPair( 6, mn[6] ) ); map1.insert( MoneyPair( 7, mn[7] ) ); MoneyMap out; MoneyMap::iterator out_itr( out.begin() ); set_intersection( map1.begin(), map1.end(), map2.begin(), map2.end(), inserter( out, out_itr ) ); cout << "intersection has " << out.size() << " elements." << endl; return 0; } Since the pair labelled (3) and (4) appear in both maps, I was expecting that I'd get 2 elements in the intersection, but no, I get: intersection has 0 elements. I'm sure this is something to do with the comparitor on the map / pair but can't figure it out.

    Read the article

  • Spring constructor injection error

    - by Jeune
    I am getting the following error for a bean in my application context: Related cause: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'businessLogicContext' d efined in class path resource [activemq-jms-consumer.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.String]: Could not convert constructor argument value of type [java.util.ArrayList] to required type [java.lang.String]: Failed to convert value of type [java.util.ArrayList] to required type [java.lang.Stri ng]; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [java.util.ArrayList] to requi red type [java.lang.String]: no matching editors or conversion strategy found at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:53 4) at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:18 6) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAuto wireCapableBeanFactory.java:855) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutow ireCapableBeanFactory.java:765) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCap ableBeanFactory.java:412) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBea nFactory.java:383) at java.security.AccessController.doPrivileged(Native Method) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapab leBeanFactory.java:353) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:245) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegis try.java:169) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:242) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListable BeanFactory.java:400) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplic ationContext.java:736) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:369) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java :123) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java :66) Here is my bean: <bean id="businessLogicContext" class="org.springframework.context.support.ClassPathXmlApplicationContext" depends-on="resolveProperty"> <constructor-arg index="0"> <list> <value>jms-applicationContext.xml</value> <value>jms-managerBeanContext.xml</value> <value>jms-daoContext.xml</value> <value>jms-serviceContext.xml</value> </list> </constructor-arg> </bean> I don't know what's wrong, I have googled how to inject a string array via constructor injection and the way I do it above seems okay.

    Read the article

  • How to change quicksort to output elements in descending order?

    - by masato-san
    Hi, I wrote a quicksort algorithm however, I would like to make a change somewhere so that this quicksort would output elements in descending order. I searched and found that I can change the comparison operator (<) in partition() to other way around (like below). //This is snippet from partition() function while($array[$l] < $pivot) { $l++; } while($array[$r] > $pivot) { $r--; } But it is not working.. If I quicksort the array below, $array = (3,9,5,7); should be: $array = (9,7,5,3) But actual output is: $array = (3,5,7,9) Below is my quicksort which trying to output elements in descending order. How should I make change to sort in descending order? If you need any clarification please let me know. Thanks! $array = (3,9,5,7); $app = new QuicksortDescending(); $app->quicksort($array, 0, count($array)); print_r($array); class QuicksortDescending { public function partitionDesc(&$array, $left, $right) { $l = $left; $r = $right; $pivot = $array[($right+$left)/2]; while($l <= $r) { while($array[$l] > $pivot) { $l++; } while($array[$r] < $pivot) { $r--; } if($l <= $r) {// if L and R haven't cross $this->swap($array, $l, $r); $l ++; $j --; } } return $l; } public function quicksortDesc(&$array, $left, $right) { $index = $this->partition($array, $left, $right); if($left < $index-1) { //if there is more than 1 element to sort on right subarray $this->quicksortDesc($array, $left, $index-1); } if($index < $right) { //if there is more than 1 element to sort on right subarray $this->quicksortDesc($array, $index, $right); } } }

    Read the article

  • List<> of objects, different types, sort and pull out types individually?

    - by Brazos
    I've got a handful of products, any, all, or none of which may be associated with a specific submission. All 7 products are subclasses of the class Product. I need to store all the products associated with a submission, and then retrieve them and their field data on my presentation layer. I've been using a List, and List, but when I use the OfType, I throw an error saying that I can't implicitly convert systems.generic.IEnumerable to type 'Product'. I've tried to cast, but to no avail. When I use prodlist.OfType<EPL>(); there are no errors, but when I try and store that in an instance of EPL "tempEpl", I get the aforementioned cast-related error. What gives? Code below. ProductService pserv = new ProductService(); IList<object> prodlist = pserv.getProductById(x); EPL tempEpl = new EPL(); if ((prodlist.OfType<EPL>()) != null) { tempEpl = prodlist.OfType<EPL>(); // this throws a conversion error. } the Data layer List<object> TempProdList = new List<object>(); conn.Open(); SqlCommand EplCmd = new SqlCommand(EPLQuery, conn); SqlDataReader EplRead = null; EplRead = EplCmd.ExecuteReader(); EPL TempEpl = new EPL(); if (EplRead.Read()) { TempEpl.Entity1 = EplRead.GetString(0); TempEpl.Employees1 = EplRead.GetInt32(1); TempEpl.CA1 = EplRead.GetInt32(2); TempEpl.MI1 = EplRead.GetInt32(3); TempEpl.NY1 = EplRead.GetInt32(4); TempEpl.NJ1 = EplRead.GetInt32(5); TempEpl.PrimEx1 = EplRead.GetInt32(6); TempEpl.EplLim1 = EplRead.GetInt32(7); TempEpl.EplSir1 = EplRead.GetInt32(8); TempEpl.Premium1 = EplRead.GetInt32(9); TempEpl.Wage1 = EplRead.GetInt32(10); TempEpl.Sublim1 = EplRead.GetInt32(11); TempProdList.Add(TempEpl); }

    Read the article

  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

    Read the article

  • When to call glEnable(GL_FRAMEBUFFER_SRGB)?

    - by Steven Lu
    I have a rendering system where I draw to an FBO with a multisampled renderbuffer, then blit it to another FBO with a texture in order to resolve the samples in order to read off the texture to perform post-processing shading while drawing to the backbuffer (FBO index 0). Now I'd like to get some correct sRGB output... The problem is the behavior of the program is rather inconsistent between when I run it on OS X and Windows and this also changes depending on the machine: On Windows with the Intel HD 3000 it will not apply the sRGB nonlinearity but on my other machine with a Nvidia GTX 670 it does. On the Intel HD 3000 in OS X it will also apply it. So this probably means that I'm not setting my GL_FRAMEBUFFER_SRGB enable state at the right points in the program. However I can't seem to find any tutorials that actually tell me when I ought to enable it, they only ever mention that it's dead easy and comes at no performance cost. I am currently not loading in any textures so I haven't had a need to deal with linearizing their colors yet. To force the program to not simply spit back out the linear color values, what I have tried is simply comment out my glDisable(GL_FRAMEBUFFER_SRGB) line, which effectively means this setting is enabled for the entire pipeline, and I actually redundantly force it back on every frame. I don't know if this is correct or not. It certainly does apply a nonlinearization to the colors but I can't tell if this is getting applied twice (which would be bad). It could apply the gamma as I render to my first FBO. It could do it when I blit the first FBO to the second FBO. Why not? I've gone so far as to take screen shots of my final frame and compare raw pixel color values to the colors I set them to in the program: I set the input color to RGB(1,2,3) and the output is RGB(13,22,28). That seems like quite a lot of color compression at the low end and leads me to question if the gamma is getting applied multiple times. I have just now gone through the sRGB equation and I can verify that the conversion seems to be only applied once as linear 1/255, 2/255, and 3/255 do indeed map to sRGB 13/255, 22/255, and 28/255 using the equation 1.055*C^(1/2.4)+0.055. Given that the expansion is so large for these low color values it really should be obvious if the sRGB color transform is getting applied more than once. So, I still haven't determined what the right thing to do is. does glEnable(GL_FRAMEBUFFER_SRGB) only apply to the final framebuffer values, in which case I can just set this during my GL init routine and forget about it hereafter?

    Read the article

  • UDP Tracker not responding

    - by kelton52
    Alright, so I'm trying to connect to UDP trackers using c#, but I never get a response. I also don't get any errors. Here's my code. namespace UDPTester { class MainClass { public static bool messageReceived = false; public static Random Random = new Random(); public static void LOG(string format, params object[] args) { Console.WriteLine (format,args); } public static void Main (string[] args) { LOG ("Creating Packet..."); byte[] packet; using(var stream = new MemoryStream()) { var bc = new MiscUtil.Conversion.BigEndianBitConverter(); using(var br = new MiscUtil.IO.EndianBinaryWriter(bc,stream)) { LOG ("Magic Num: {0}",(Int64)0x41727101980); br.Write (0x41727101980); br.Write((Int32)0); br.Write ((Int32)Random.Next()); packet = stream.ToArray(); LOG ("Packet Size: {0}",packet.Length); } } LOG ("Connecting to tracker..."); var client = new System.Net.Sockets.UdpClient("tracker.openbittorrent.com",80); UdpState s = new UdpState(); s.e = client.Client.RemoteEndPoint; s.u = client; StartReceiving(s); LOG ("Sending Packet..."); client.Send(packet,packet.Length); while(!messageReceived) { Thread.Sleep(1000); } LOG ("Ended"); } public static void StartReceiving(UdpState state) { state.u.BeginReceive(ReceiveCallback,state); } public static void ReceiveCallback(IAsyncResult ar) { UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u; IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e; Byte[] receiveBytes = u.EndReceive(ar, ref e); string receiveString = Encoding.ASCII.GetString(receiveBytes); LOG("Received: {0}", receiveString); messageReceived = true; StartReceiving((UdpState)ar.AsyncState); } } public class UdpState { public UdpClient u; public EndPoint e; } } I was using a normal BinaryWriter, but that didn't work, and I read somewhere that it wants it's data in BigEndian. This doesn't work for any of the UDP trackers I've found, any ideas why I'm not getting a response? Did they maybe change the protocol and not tell anyone? HTTP trackers all work fine. Trackers I've tried udp://tracker.publicbt.com:80 udp://tracker.ccc.de:80 udp://tracker.istole.it:80 Also, I'm not interested in using MonoTorrent(and when I was using it, the UDP didn't work anyways). Protocol Sources http://xbtt.sourceforge.net/udp_tracker_protocol.html http://www.rasterbar.com/products/libtorrent/udp_tracker_protocol.html

    Read the article

  • Supporting multiple instances of a plugin DLL with global data

    - by Bruno De Fraine
    Context: I converted a legacy standalone engine into a plugin component for a composition tool. Technically, this means that I compiled the engine code base to a C DLL which I invoke from a .NET wrapper using P/Invoke; the wrapper implements an interface defined by the composition tool. This works quite well, but now I receive the request to load multiple instances of the engine, for different projects. Since the engine keeps the project data in a set of global variables, and since the DLL with the engine code base is loaded only once, loading multiple projects means that the project data is overwritten. I can see a number of solutions, but they all have some disadvantages: You can create multiple DLLs with the same code, which are seen as different DLLs by Windows, so their code is not shared. Probably this already works if you have multiple copies of the engine DLL with different names. However, the engine is invoked from the wrapper using DllImport attributes and I think the name of the engine DLL needs to be known when compiling the wrapper. Obviously, if I have to compile different versions of the wrapper for each project, this is quite cumbersome. The engine could run as a separate process. This means that the wrapper would launch a separate process for the engine when it loads a project, and it would use some form of IPC to communicate with this process. While this is a relatively clean solution, it requires some effort to get working, I don't now which IPC technology would be best to set-up this kind of construction. There may also be a significant overhead of the communication: the engine needs to frequently exchange arrays of floating-point numbers. The engine could be adapted to support multiple projects. This means that the global variables should be put into a project structure, and every reference to the globals should be converted to a corresponding reference that is relative to a particular project. There are about 20-30 global variables, but as you can imagine, these global variables are referenced from all over the code base, so this conversion would need to be done in some automatic manner. A related problem is that you should be able to reference the "current" project structure in all places, but passing this along as an extra argument in each and every function signature is also cumbersome. Does there exist a technique (in C) to consider the current call stack and find the nearest enclosing instance of a relevant data value there? Can the stackoverflow community give some advice on these (or other) solutions?

    Read the article

  • c++ compile error

    - by Niranjan
    Hi, I am trying to develop abstract design pattern code for one of my project as below.. But, I am not able to compile the code ..giving some compile errors(like "conversion from 'ProductA1 *' to 'ProductA *' exists, but is inaccessible" ).. Can any one please help me out in this... #include "stdafx.h" #include <iostream> using namespace std; class ProductA { public: virtual void Operation1()=0; virtual void Operation2()=0; }; class ProductA1 : ProductA { public: virtual void Operation1() {cout<<"PD ProductA1 Operation1"<<endl; } virtual void Operation2() {cout<<"PD ProductA1 Operation2"<<endl; } }; class ProductA2 : ProductA { public: virtual void Operation1() {cout<<"DT ProductA2 Operation1"<<endl; } virtual void Operation2() {cout<<"DT ProductA2 Operation2"<<endl; } }; //------------------------------------------------------------- class ProductB { public: virtual void Operation3()=0; virtual void Operation4()=0; }; class ProductB1 : ProductB { public: void Operation3() { cout<<"PD ProductB1 Operation3"<<endl; } void Operation4() { cout<<"PD ProductB1 Operation4"<<endl; } }; class ProductB2 : ProductB { public: void Operation3() { cout<<"DT ProductB2 Operation3"<<endl; } void Operation4() { cout<<"DT ProductB2 Operation4"<<endl; } }; //--------------- abstrct factory --------------------------- class Factory { public: virtual ProductA* CreateA () =0; virtual ProductB* CreateB ()=0; }; class Factory1 : Factory { public: ProductA* CreateA () { return new ProductA1(); } ProductB* CreateB () { return new ProductB1(); } }; class Factory2 : Factory { public: ProductA* CreateA () { return new ProductA2(); } ProductB* CreateB () { return new ProductB2(); } }; //--------------------- client -------------------------------- int _tmain(int argc, _TCHAR* argv[]) { Factory* pf = new Factory1(); ProductA *pa = pf->CreateA(); pa->Operation1(); pa->Operation2(); ProductB *pb = pf->CreateB(); pb->Operation3(); pb->Operation4(); return 0; }

    Read the article

  • initializing a vector of custom class in c++

    - by Flamewires
    Hey basically Im trying to store a "solution" and create a vector of these. The problem I'm having is with initialization. Heres my class for reference class Solution { private: // boost::thread m_Thread; int itt_found; int dim; pfn_fitness f; double value; std::vector<double> x; public: Solution(size_t size, int funcNo) : itt_found(0), x(size, 0.0), value(0.0), dim(30), f(Eval_Functions[funcNo]) { for (int i = 1; i < (int) size; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[funcNo]; } } Solution() : itt_found(0), x(31, 0.0), value(0.0), dim(30), f(Eval_Functions[1]) { for (int i = 1; i < 31; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[1]; } } Solution operator= (Solution S) { x = S.GetX(); itt_found = S.GetIttFound(); dim = S.GetDim(); f = S.GetFunc(); value = S.GetValue(); return *this; } void start() { value = f (dim, x); } /* plus additional getter/setter methods*/ } Solution S(30, 1) or Solution(2, 5) work and initalizes everything, but I need X of these solution objects. std::vector<Solution> Parents(X) will create X solutions with the default constructor and i want to construct using the (int, int) constructor. Is there any easy(one liner?) way to do this? Or would i have to do something like: size_t numparents = 10; vector<Solution> Parents; Parents.reserve(numparents); for (int i = 0; i<(int)numparents; i++) { Solution S(31, 0); Parents.push_back(S); }

    Read the article

  • Modify audio pitch of recorded clip (m4v)

    - by devcube
    I'm writing an app in which I'm trying to change the pitch of the audio when I'm recording a movie (.m4v). Or by modifying the audio pitch of the movie afterwards. I want the end result to be a movie (.m4v) that has the original length (i.e. same visual as original) but with modified sound pitch, e.g. a "chipmunk voice". A realtime conversion is to prefer if possible. I've read alot about changing audio pitch in iOS but most examples focus on playback, i.e. playing the sound with a different pitch. In my app I'm recording a movie (.m4v / AVFileTypeQuickTimeMovie) and saving it using standard AVAssetWriter. When saving the movie I have access to the following elements where I've tried to manipulate the audio (e.g. modify the pitch): audio buffer (CMSampleBufferRef) audio input writer (AVAssetWriterAudioInput) audio input writer options (e.g. AVNumberOfChannelsKey, AVSampleRateKey, AVChannelLayoutKey) asset writer (AVAssetWriter) I've tried to hook into the above objects to modify the audio pitch, but without success. I've also tried with Dirac as described here: Real Time Pitch Change In iPhone Using Dirac And OpenAL with AL_PITCH as described here: Piping output from OpenAL into a buffer And the "BASS" library from un4seen: Change Pitch/Tempo In Realtime I haven't found success with any of the above libs, most likely because I don't really know how to use them, and where to hook them into the audio saving code. There seems to be alot of librarys that have similar effects but focuses on playback or custom recording code. I want to manipulate the audio stream I've already got (AVAssetWriterAudioInput) or modify the saved movie clip (.m4v). I want the video to be unmodifed visually, i.e. played at the same speed. But I want the audio to go faster (like a chipmunk) or slower (like a ... monster? :)). Do you have any suggestions how I can modify the pitch in either real time (when recording the movie) or afterwards by converting the entire movie (.m4v file)? Should I look further into Dirac, OpenAL, SoundTouch, BASS or some other library? I want to be able to share the movie to others with modified audio, that's the reason I can't rely on modifying the pitch for playback only. Any help is appreciated, thanks!

    Read the article

  • C++ string sort like a human being?

    - by Walter Nissen
    I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with a possible answer, but it uses various library functions, as does "Sorting Strings for Humans with IComparer". Below is a test case that currently fails: #include <set> #include <iterator> #include <iostream> #include <vector> #include <cassert> template <typename T> struct LexicographicSort { inline bool operator() (const T& lhs, const T& rhs) const{ std::ostringstream s1,s2; s1 << toLower(lhs); s2 << toLower(rhs); bool less = s1.str() < s2.str(); std::cout<<s1.str()<<" "<<s2.str()<<" "<<less<<"\n"; return less; } inline std::string toLower(const std::string& str) const { std::string newString(""); for (std::string::const_iterator charIt = str.begin(); charIt!=str.end();++charIt) { newString.push_back(std::tolower(*charIt)); } return newString; } }; int main(void) { const std::string reference[5] = {"ab","B","c1","c2","c10"}; std::vector<std::string> referenceStrings(&(reference[0]), &(reference[5])); //Insert in reverse order so we know they get sorted std::set<std::string,LexicographicSort<std::string> > strings(referenceStrings.rbegin(), referenceStrings.rend()); std::cout<<"Items:\n"; std::copy(strings.begin(), strings.end(), std::ostream_iterator<std::string>(std::cout, "\n")); std::vector<std::string> sortedStrings(strings.begin(), strings.end()); assert(sortedStrings == referenceStrings); }

    Read the article

  • C#/.NET Project - Am I setting things up correctly?

    - by JustLooking
    1st solution located: \Common\Controls\Controls.sln and its project: \Common\Controls\Common.Controls\Common.Controls.csproj Description: This is a library that contains this class: public abstract class OurUserControl : UserControl { // Variables and other getters/setters common to our UserControls } 2nd solution located: \AControl\AControl.sln and its project: \AControl\AControl\AControl.csproj Description: Of the many forms/classes, it will contain this class: using Common.Controls; namespace AControl { public partial class AControl : OurUserControl { // The implementation } } A note about adding references (not sure if this is relevant): When I add references (for projects I create), using the names above: 1. I add Common.Controls.csproj to AControl.sln 2. In AControl.sln I turn off the build of Common.Controls.csproj 3. I add the reference to Common.Controls (by project) to AControl.csproj. This is the (easiest) way I know how to get Debug versions to match Debug References, and Release versions to match Release References. Now, here is where the issue lies (the 3rd solution/project that actually utilizes the UserControl): 3rd solution located: \MainProj\MainProj.sln and its project: \MainProj\MainProj\MainProj.csproj Description: Here's a sample function in one of the classes: private void TestMethod<T>() where T : Common.Controls.OurUserControl, new() { T TheObject = new T(); TheObject.OneOfTheSetters = something; TheObject.AnotherOfTheSetters = something_else; // Do stuff with the object } We might call this function like so: private void AnotherMethod() { TestMethod<AControl.AControl>(); } This builds, runs, and works. No problem. The odd thing is after I close the project/solution and re-open it, I have red squigglies everywhere. I bring up my error list and I see tons of errors (anything that deals with AControl will be noted as an error). I'll see errors such as: The type 'AControl.AControl' cannot be used as type parameter 'T' in the generic type or method 'MainProj.MainClass.TestMethod()'. There is no implicit reference conversion from 'AControl.AControl' to 'Common.Controls.OurUserControl'. or inside the actual method (the properties located in the abstract class): 'AControl.AControl' does not contain a definition for 'OneOfTheSetters' and no extension method 'OneOfTheSetters' accepting a first argument of type 'AControl.AControl' could be found (are you missing a using directive or an assembly reference?) Meanwhile, I can still build and run the project (then the red squigglies go away until I re-open the project, or close/re-open the file). It seems to me that I might be setting up the projects incorrectly. Thoughts?

    Read the article

  • casting doubles to integers in order to gain speed

    - by antirez
    Hello all, in Redis (http://code.google.com/p/redis) there are scores associated to elements, in order to take this elements sorted. This scores are doubles, even if many users actually sort by integers (for instance unix times). When the database is saved we need to write this doubles ok disk. This is what is used currently: snprintf((char*)buf+1,sizeof(buf)-1,"%.17g",val); Additionally infinity and not-a-number conditions are checked in order to also represent this in the final database file. Unfortunately converting a double into the string representation is pretty slow. While we have a function in Redis that converts an integer into a string representation in a much faster way. So my idea was to check if a double could be casted into an integer without lost of data, and then using the function to turn the integer into a string if this is true. For this to provide a good speedup of course the test for integer "equivalence" must be fast. So I used a trick that is probably undefined behavior but that worked very well in practice. Something like that: double x = ... some value ... if (x == (double)((long long)x)) use_the_fast_integer_function((long long)x); else use_the_slow_snprintf(x); In my reasoning the double casting above converts the double into a long, and then back into an integer. If the range fits, and there is no decimal part, the number will survive the conversion and will be exactly the same as the initial number. As I wanted to make sure this will not break things in some system, I joined #c on freenode and I got a lot of insults ;) So I'm now trying here. Is there a standard way to do what I'm trying to do without going outside ANSI C? Otherwise, is the above code supposed to work in all the Posix systems that currently Redis targets? That is, archs where Linux / Mac OS X / *BSD / Solaris are running nowaday? What I can add in order to make the code saner is an explicit check for the range of the double before trying the cast at all. Thank you for any help.

    Read the article

  • Remove never-run call to templated function, get allocation error on run-time

    - by Narfanator
    First off, I'm a bit at a loss as to how to ask this question. So I'm going to try throwing lots of information at the problem. Ok, so, I went to completely redesign my test project for my experimental core library thingy. I use a lot of template shenanigans in the library. When I removed the "user" code, the tests gave me a memory allocation error. After quite a bit of experimenting, I narrowed it down to this bit of code (out of a couple hundred lines): void VOODOO(components::switchBoard &board){ board.addComponent<using_allegro::keyInputs<'w'> >(); } Fundementally, what's weirding me out is that it appears that the act of compiling this function (and the template function it then uses, and the template functions those then use...), makes this bug not appear. This code is not being run. Similar code (the same, but for different key vals) occurs elsewhere, but is within Boost TDD code. I realize I certainly haven't given enough information for you to solve it for me; I tried, but it more-or-less spirals into most of the code base. I think I'm most looking for "here's what the problem could be", "here's where to look", etc. There's something that's happening during compile because of this line, but I don't know enough about that step to begin looking. Sooo, how can a (presumably) compilied, but never actually run, bit of templated code, when removed, cause another part of code to fail? Error: Unhandled exceptionat 0x6fe731ea (msvcr90d.dll) in Switchboard.exe: 0xC0000005: Access violation reading location 0xcdcdcdc1. Callstack: operator delete(void * pUser Data) allocator< class name related to key inputs callbacks ::deallocate vector< same class ::_Insert_n(...) vector< " " ::insert(...) vector<" "::push_back(...) It looks like maybe the vector isn't valid, because _MyFirst and similar data members are showing values of 0xcdcdcdcd in the debugger. But the vector is a member variable...

    Read the article

  • L-Soft LISTSERV TCPGUI Interface for PHP Creation

    - by poolnoodl
    I'm trying to use LISTSERV's "API" in PHP. L-Soft calls this TCPGUI, and essentially, you can request data like over Telnet. To do this, I'm using PHP's TCP socket functions. I've seen this done in other languages but can't quite convert it to PHP. I can connect, I can change set ASCII or BINARY mode. But I can never quite craft the header packet the way I need to authenticate, so I'm thinking I'm messing up my conversion. C: http://www.lsoft.com/manuals/16.0/htmlhelp/advanced%20topics/TCPGUI.html#2334328 $origin = '[email protected]'; $pwd = 'password'; $host = "example.com"; $port = 2306; $email = "[email protected]"; $list = "mailinglist"; $command = "Query $list FOR $email"; $fp = stream_socket_client("tcp://$host:$port", $errno, $errstr, 30); $cmd = $command . " PW=" . $pwd; $len = strlen($cmd); $orglen = strlen($origin); $n = $len + $orglen + 1; $headerPacket[0] = "1"; $headerPacket[1] = "B"; $headerPacket[2] = "\r"; $headerPacket[3] = "\n"; $headerPacket[4] = ord($n / 256); $headerPacket[5] = ord($n + 255); $headerPacket[6] = ord($orglen); for ($i = 0; $i < $orglen; $i++) { $headerPacket[$i + 7] = ord($origin[$i]); } for ($i = 0; $i < $len; $i++) { $cmdPacket[$i] = ord($cmd[$i]); } fwrite($fp, implode($headerPacket)); while (!feof($fp)) { echo fgets($fp, 1024); } Any thoughts on where I'm going wrong? I'd much appreciate it if anyone could point me toward some code to do this, days of googling and searching here on SO has only lead me to examples in other languages. Of course, if you know C (or Java or Perl as linked below in my comment to bypass the spam filter), PHP, and socket programming fairly well, you could probably rewrite the whole of the code in an hour, maybe a few minutes. You'd have my eternal thanks for that.

    Read the article

  • Converting generic type to it's base and vice-versa

    - by Pajci
    Can someone help me with the conversion I am facing in enclosed code ... I commented the lines of code, where I am having problem. Is this even the right way to achieve this ... what I am trying to do, is forward responses of specified type to provided callback. public class MessageBinder { private class Subscriber<T> : IEquatable<Subscriber<T>> where T : Response { ... } private readonly Dictionary<Type, List<Subscriber<Response>>> bindings; public MessageBinder() { this.bindings = new Dictionary<Type, List<Subscriber<Response>>>(); } public void Bind<TResponse>(short shortAddress, Action<ZigbeeAsyncResponse<TResponse>> callback) where TResponse : Response { List<Subscriber<TResponse>> subscribers = this.GetSubscribers<TResponse>(); if (subscribers != null) { subscribers.Add(new Subscriber<TResponse>(shortAddress, callback)); } else { var subscriber = new Subscriber<TResponse>(shortAddress, callback); // ERROR: cannot convert from 'List<Subscriber<TResponse>>' to 'List<Subscriber<Response>>' ... tried LINQ Cast operator - does not work either this.bindings.Add(typeof(TResponse), new List<Subscriber<TResponse>> { subscriber }); } } public void Forward<TResponse>(TResponse response) where TResponse : Response { var subscribers = this.GetSubscribers<TResponse>(); if (subscribers != null) { Subscriber<TResponse> subscriber; Type responseType = typeof (TResponse); if (responseType.IsSubclassOf(typeof (AFResponse))) { // ERROR: Cannot convert type 'TResponse' to 'AFResponse' ... tried cast to object first, works, but is this the right way? var afResponse = (AFResponse)response; subscriber = subscribers.SingleOrDefault(s => s.ShortAddress == afResponse.ShortAddress); } else { subscriber = subscribers.First(); } if (subscriber != null) { subscriber.Forward(response); } } } private List<Subscriber<TResponse>> GetSubscribers<TResponse>() where TResponse : Response { List<Subscriber<Response>> subscribers; this.bindings.TryGetValue(typeof(TResponse), out subscribers); // ERROR: How can I cast List<Subscriber<Response>> to List<Subscriber<TResponse>>? return subscribers; } } Thank you for any help :)

    Read the article

  • objective C convert NSString to unsigned

    - by user1501354
    I have changed my question. I want to convert an NSString to an unsigned int. Why? Because I want to do parallel payment in PayPal. Below I have given my coding in which I want to convert the NSString to an unsigned int. My query is: //optional, set shippingEnabled to TRUE if you want to display shipping //options to the user, default: TRUE [PayPal getPayPalInst].shippingEnabled = TRUE; //optional, set dynamicAmountUpdateEnabled to TRUE if you want to compute //shipping and tax based on the user's address choice, default: FALSE [PayPal getPayPalInst].dynamicAmountUpdateEnabled = TRUE; //optional, choose who pays the fee, default: FEEPAYER_EACHRECEIVER [PayPal getPayPalInst].feePayer = FEEPAYER_EACHRECEIVER; //for a payment with multiple recipients, use a PayPalAdvancedPayment object PayPalAdvancedPayment *payment = [[PayPalAdvancedPayment alloc] init]; payment.paymentCurrency = @"USD"; // A payment note applied to all recipients. payment.memo = @"A Note applied to all recipients"; //receiverPaymentDetails is a list of PPReceiverPaymentDetails objects payment.receiverPaymentDetails = [NSMutableArray array]; NSArray *emailArray = [NSArray arrayWithObjects:@"[email protected]",@"[email protected]", nil]; for (int i = 1; i <= 2; i++) { PayPalReceiverPaymentDetails *details = [[PayPalReceiverPaymentDetails alloc] init]; // Customize the payment notes for one of the three recipient. if (i == 2) { details.description = [NSString stringWithFormat:@"Component %d", i]; } details.recipient = [NSString stringWithFormat:@"%@",[emailArray objectAtIndex:i-1]]; unsigned order; if (i==1) { order = [[feeArray objectAtIndex:0] unsignedIntValue]; } if (i==2) { order = [[amountArray objectAtIndex:0] unsignedIntValue]; } //subtotal of all items for this recipient, without tax and shipping details.subTotal = [NSDecimalNumber decimalNumberWithMantissa:order exponent:-4 isNegative:FALSE]; //invoiceData is a PayPalInvoiceData object which contains tax, shipping, and a list of PayPalInvoiceItem objects details.invoiceData = [[PayPalInvoiceData alloc] init]; //invoiceItems is a list of PayPalInvoiceItem objects //NOTE: sum of totalPrice for all items must equal details.subTotal //NOTE: example only shows a single item, but you can have more than one details.invoiceData.invoiceItems = [NSMutableArray array]; PayPalInvoiceItem *item = [[PayPalInvoiceItem alloc] init]; item.totalPrice = details.subTotal; [details.invoiceData.invoiceItems addObject:item]; [payment.receiverPaymentDetails addObject:details]; } [[PayPal getPayPalInst] advancedCheckoutWithPayment:payment]; Can anybody tell me how to do this conversion? Thanks and regards in advance.

    Read the article

  • Ruby/Rails - Add records to an object with each loop iteration / Object vs Arrays

    - by ChrisWesAllen
    I'm trying to figure out how to add records to an existing object for each iteration of a loop. I'm having a hard time discovering the difference between an object and an array. I have this @events = Event.find(1) @loops = Choices.find(:all, :limit => 5) #so loop for 5 instances of choice model for loop in @loops @events = Event.find(:all,:conditions => ["event.id = ?", loop.event_id ]) end I'm trying to add a new events to the existing @events object based on the id of whatever the loop variable is. But the ( = ) operator just creates a new instance of the @events object. I tried ( += ) and ( << ) as operators but got the error "You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil" I tried created an array events = [] events << Event.find(1) @loops = Choices.find(:all, :limit => 5) #so loop for 5 instances of choice model for loop in @loops events << Event.find(:all,:conditions => ["event.id = ?", loop.event_id ]) end But I dont know how to call that arrays attributes within the view With objects I was able do create a loop within the view and call all the attributes of that object as well... <table> <% for event in @events %> <tr> <td><%= link_to event.title, event %></td> <td><%= event.start_date %></td> <td><%= event.price %></td> </tr> <% end %> </table> How could i do this with an array set? So the questions are 1) Whats the difference between arrays and objects? 2) Is there a way to add into the existing object for each iteration? 3) If I use an array, is there a way to call the attributes for each array record within the view?

    Read the article

  • Specializing a template on a lambda in C++0x

    - by Tony A.
    I've written a traits class that lets me extract information about the arguments and type of a function or function object in C++0x (tested with gcc 4.5.0). The general case handles function objects: template <typename F> struct function_traits { template <typename R, typename... A> struct _internal { }; template <typename R, typename... A> struct _internal<R (F::*)(A...)> { // ... }; typedef typename _internal<decltype(&F::operator())>::<<nested types go here>>; }; Then I have a specialization for plain functions at global scope: template <typename R, typename... A> struct function_traits<R (*)(A...)> { // ... }; This works fine, I can pass a function into the template or a function object and it works properly: template <typename F> void foo(F f) { typename function_traits<F>::whatever ...; } int f(int x) { ... } foo(f); What if, instead of passing a function or function object into foo, I want to pass a lambda expression? foo([](int x) { ... }); The problem here is that neither specialization of function_traits<> applies. The C++0x draft says that the type of the expression is a "unique, unnamed, non-union class type". Demangling the result of calling typeid(...).name() on the expression gives me what appears to be gcc's internal naming convention for the lambda, main::{lambda(int)#1}, not something that syntactically represents a C++ typename. In short, is there anything I can put into the template here: template <typename R, typename... A> struct function_traits<????> { ... } that will allow this traits class to accept a lambda expression?

    Read the article

< Previous Page | 183 184 185 186 187 188 189 190 191 192 193 194  | Next Page >