Search Results

Search found 3137 results on 126 pages for 'digital signature'.

Page 102/126 | < Previous Page | 98 99 100 101 102 103 104 105 106 107 108 109  | Next Page >

• Gridview Paging via ObjectDataSource: Why is maximumRows being set to -1?

  - by Bryan

  So before I tried custom gridview paging via ObjectDataSource... I think I read every tutorial known to man just to be sure I got it. It didn't look like rocket science. I've set the AllowPaging = True on my gridview. I've specified PageSize="10" on my gridview. I've set EnablePaging="True" on the ObjectDataSource. I've added the 2 paging parms (maximumRows & startRowIndex) to my business object's select method. I've created an analogous "count" method with the same signature as the select method. The only problem I seem to have is during execution... the ObjectDataSource is supplying my business object with a maximumRows value of -1 and I can't for the life of me figure out why. I've searched to the end of the web for anyone else having this problem and apparently I'm the only one. The StartRowIndex parameter seems to be working just fine. Any ideas?

  Read the article

• .NET consumer of ActiveX throwing TargetParameterCountException

  - by DevSolo

  I have a .NET (3.5 w/ Dev Studio 2008) app that hosts a visual Active X (written in C++ w/ Dev Studio 2003). Have access to all sources, but can't easily move the Active X control up to 2008. This as worked fine in the past. Made some changes to the Active X control and now, when calling one method on the Active X, I'm getting a TargetParameterCountException 100% of the time. The signature of the Active X method is: LONG CMyActive::License(LPCTSTR string1, LPCTSTR string2, LONG long1, LPCTSTR string3, LPCTSTR string4); When viewing the method in object browser of reflector, .NET sees it as: public virtual int License(string string1, string string2, int long1, string string3, string string4) I renamed the parameters for demonstration purpose (boss gets twitchy about any code). I left the method name, as it could be relevant. There are method calls prior that work. I just can't seen to figure out why I'm all of a sudden getting this exception. The HRESULT is 0x8002000e and a quick search seems to indicate that's a general one. Thanks to all for reading.

  Read the article

• How to create a generic C free function .

  - by nomemory

  I have some C structures related to a 'list' data structure. They look like this. struct nmlist_element_s { void *data; struct nmlist_element_s *next; }; typedef struct nmlist_element_s nmlist_element; struct nmlist_s { void (*destructor)(void *data); int (*cmp)(const void *e1, const void *e2); unsigned int size; nmlist_element *head; nmlist_element *tail; }; typedef struct nmlist_s nmlist; This way I can have different data types being hold in "nmlist_element-data" . The "constructor" (in terms of OOP) has the following signature: nmlist *nmlist_alloc(void (*destructor)(void *data)); Where "destructor" is specific function that de-allocated "data" (being hold by the nmlist_element). If I want to have a list containing integers as data, my "destructor" would like this: void int_destructor(void *data) { free((int*)data); } Still i find it rather "unfriendly" for me to write a destructor functions for every simple primitive data type. So is there a trick to write something like this ? (for primitives): void "x"_destructor(void *data, "x") { free(("x" *)data); } PS: I am not a macro fan myself, and in my short experience regarding C, i don't use them, unless necessary.

  Read the article

• c++ callback syntax in a class

  - by Mr Bell

  I am trying to figure out the syntax to register a callback with this 3rd party software. I think it is probably a basic question, I just am not too familiar with c++. They have a method for registering a callback function so their code can call a function in my code when an event happens. They provided a working example that registers the callback from the main file, but I want to know how to do it when working inside a class Their method signature: smHTRegisterHeadPoseCallback(smEngineHandle engine_handle, void *user_data, smHTHeadPoseCallback callback_fun); Working example from the main file: void STDCALL receiveHeadPose(void *,smEngineHeadPoseData head_pose, smCameraVideoFrame video_frame) { ... } void main() { ... smHTRegisterHeadPoseCallback(engine_handle,0,receiveHeadPose) ... } But I want to use this from my class MyClass.h class FaceEngine { public: void STDCALL receiveFaceData(void *, smEngineFaceData face_data, smCameraVideoFrame video_frame); ... MyClass.cpp void FaceEngine::Start(void) { rc = smHTRegisterFaceDataCallback(hFaceAPIEngine,0,&FaceEngine::receiveFaceData); ... Results in this compiler error: Error 1 error C2664: 'smHTRegisterFaceDataCallback' : cannot convert parameter 3 from 'void (__stdcall FaceEngine::* )(void *,smEngineFaceData,smCameraVideoFrame)' to 'smHTFaceDataCallback' d:\stuff\programming\visual studio 2008\projects\tut02_vertices\faceengine.cpp 43 Beard If my question isn't clear please let me know how I can clarify.

  Read the article

• Connecting an overloaded PyQT signal using new-style syntax

  - by Claudio

  I am designing a custom widget which is basically a QGroupBox holding a configurable number of QCheckBox buttons, where each one of them should control a particular bit in a bitmask represented by a QBitArray. In order to do that, I added the QCheckBox instances to a QButtonGroup, with each button given an integer ID: def populate(self, num_bits, parent = None): """ Adds check boxes to the GroupBox according to the bitmask size """ self.bitArray.resize(num_bits) layout = QHBoxLayout() for i in range(num_bits): cb = QCheckBox() cb.setText(QString.number(i)) self.buttonGroup.addButton(cb, i) layout.addWidget(cb) self.setLayout(layout) Then, each time a user would click on a checkbox contained in self.buttonGroup, I'd like self.bitArray to be notified so I can set/unset the corresponding bit in the array. For that I intended to connect QButtonGroup's buttonClicked(int) signal to QBitArray's toggleBit(int) method and, to be as pythonic as possible, I wanted to use new-style signals syntax, so I tried this: self.buttonGroup.buttonClicked.connect(self.bitArray.toggleBit) The problem is that buttonClicked is an overloaded signal, so there is also the buttonClicked(QAbstractButton*) signature. In fact, when the program is executing I get this error when I click a check box: The debugged program raised the exception unhandled TypeError "QBitArray.toggleBit(int): argument 1 has unexpected type 'QCheckBox'" which clearly shows the toggleBit method received the buttonClicked(QAbstractButton*) signal instead of the buttonClicked(int) one. So, the question is, how can we specify, using new-style syntax, that self.buttonGroup emits the buttonClicked(int) signal instead of the default overload - buttonClicked(QAbstractButton*)?

  Read the article

• Using 'or' in Java Generics declaration

  - by Shervin

  I have a method that returns an instance of Map<String, List<Foo>> x(); and another method that returns an instance of Map<String, Collection<Foo>> y(); Now if I want to dynamically add one of this Maps in my field, how can I write the generics for it to work? ie: public class Bar { private Map<String, ? extends Collection<Foo>> myMap; public void initializer() { if(notImportant) myMap = x(); //OK else myMap = y(); // !OK (Need cast to (Map<String, ? extends Collection<Foo>>) } Now is it ok that I cast to the signature even though the y() is declared as being Collection? } } If it is not ok to cast, can I somehow write this (Collection OR List) I mean, List is a Collection, so it should somehow be possible. private Map<String, Collection<Foo> | List<Foo>>> myMap;

  Read the article

• Liskov Substition and Composition

  - by FlySwat

  Let say I have a class like this: public sealed class Foo { public void Bar { // Do Bar Stuff } } And I want to extend it to add something beyond what an extension method could do....My only option is composition: public class SuperFoo { private Foo _internalFoo; public SuperFoo() { _internalFoo = new Foo(); } public void Bar() { _internalFoo.Bar(); } public void Baz() { // Do Baz Stuff } } While this works, it is a lot of work...however I still run into a problem: public void AcceptsAFoo(Foo a) I can pass in a Foo here, but not a super Foo, because C# has no idea that SuperFoo truly does qualify in the Liskov Substitution sense...This means that my extended class via composition is of very limited use. So, the only way to fix it is to hope that the original API designers left an interface laying around: public interface IFoo { public Bar(); } public sealed class Foo : IFoo { // etc } Now, I can implement IFoo on SuperFoo (Which since SuperFoo already implements Foo, is just a matter of changing the signature). public class SuperFoo : IFoo And in the perfect world, the methods that consume Foo would consume IFoo's: public void AcceptsAFoo(IFoo a) Now, C# understands the relationship between SuperFoo and Foo due to the common interface and all is well. The big problem is that .NET seals lots of classes that would occasionally be nice to extend, and they don't usually implement a common interface, so API methods that take a Foo would not accept a SuperFoo and you can't add an overload. So, for all the composition fans out there....How do you get around this limitation? The only thing I can think of is to expose the internal Foo publicly, so that you can pass it on occasion, but that seems messy.

  Read the article

• prolog - infinite rule

  - by Tom

  I have the next rules % Signature: natural_number(N)/1 % Purpose: N is a natural number. natural_number(0). natural_number(s(X)) :- natural_number(X) ackermann(0, N, s(N)). //rule 1 ackermann(s(M),0,Result):- ackermann(M,s(0),Result). //rule 2 ackermann(s(M),s(N),Result):-ackermann(M,Result1,Result),ackermann(s(M),N,Result1). //rule 3 The query is: ackermann (M,N,s(s(0))). Now, as I understood, In the third calculation, we got an infinite search (failture branch). I check it, and I got a finite search (failture branch). I'll explain: In the first, we got a substitue of M=0, N=s(0) (rule 1 - succsess!). In the second, we got a substitue of M=s(0),N=0 (rule 2 - sucsses!). But what now? I try to match M=s(s(0)) N=0, But it got a finite search - failture branch. Why the comipler doesn't write me "fail". Thank you.

  Read the article

• Using an SHA1 with Microsoft CAPI

  - by Erik Jõgi

  I have an SHA1 hash and I need to sign it. The CryptSignHash() method requires a HCRYPTHASH handle for signing. I create it and as I have the actual hash value already then set it: CryptCreateHash(cryptoProvider, CALG_SHA1, 0, 0, &hash); CryptSetHashParam(hash, HP_HASHVAL, hashBytes, 0); The hashBytes is an array of 20 bytes. However the problem is that the signature produced from this HCRYPTHASH handle is incorrect. I traced the problem down to the fact that CAPI actually doesn't use all 20 bytes from my hashBytes array. For some reason it thinks that SHA1 is only 4 bytes. To verify this I wrote this small program: HCRYPTPROV cryptoProvider; CryptAcquireContext(&cryptoProvider, NULL, NULL, PROV_RSA_FULL, 0); HCRYPTHASH hash; HCRYPTKEY keyForHash; CryptCreateHash(cryptoProvider, CALG_SHA1, keyForHash, 0, &hash); DWORD hashLength; CryptGetHashParam(hash, HP_HASHSIZE, NULL, &hashLength, 0); printf("hashLength: %d\n", hashLength); And this prints out hashLength: 4 ! Can anyone explain what I am doing wrong or why Microsoft CAPI thinks that SHA1 is 4 bytes (32 bits) instead of 20 bytes (160 bits).

  Read the article

• Existentials and Scrap your Boilerplate

  - by finnsson

  I'm writing a XML (de)serializer using Text.XML.Light and Scrap your Boilerplate (at http://github.com/finnsson/Text.XML.Generic) and so far I got working code for "normal" ADTs but I'm stuck at deserializing existentials. I got the existential data type data DataBox where DataBox :: (Show d, Eq d, Data d) => d -> DataBox and I'm trying to get this to compile instance Data DataBox where gfoldl k z (DataBox d) = z DataBox `k` d gunfold k z c = k (z DataBox) -- not OK toConstr (DataBox d) = toConstr d dataTypeOf (DataBox d) = dataTypeOf d but I can't figure out how to implement gunfold for DataBox. The error message is Text/XML/Generic.hs:274:23: Ambiguous type variable `b' in the constraints: `Eq b' arising from a use of `DataBox' at Text/XML/Generic.hs:274:23-29 `Show b' arising from a use of `DataBox' at Text/XML/Generic.hs:274:23-29 `Data b' arising from a use of `k' at Text/XML/Generic.hs:274:18-30 Probable fix: add a type signature that fixes these type variable(s) It's complaining about not being able to figure out the data type of b. I'm also trying to implement dataCast1 and dataCast2 but I think I can live without them (i.e. an incorrect implementation). I guess my questions are: Is it possible to combine existentials with Scrap your Boilerplate? If so: how do you implement gunfold for an existential data type?

  Read the article

• How can I get an IObservable<T> in Rx from a "non-standard" event?

  - by Dan Tao

  Here's what I mean. Suppose I'm working with an API that exposes events, but these events do not follow the standard EventHandler or EventHandler<TEventArgs> signature. One event might look like this, for instance: Public Event Update(ByVal sender As BaseSubscription, ByVal e As BaseEvent) Now, typically, if I want to get an IObservable<TEventArgs> from an event, I can just do this: Dim updates = Observable.FromEvent(Of UpdateEventArgs)( _ target:=updateSource, _ eventName:="Update" _ ) But this doesn't work, because the Update event is not an EventHandler<UpdateEventArgs> -- in fact, there is no UpdateEventArgs -- it's basically just its own thing. Obviously, I could define my own class deriving from EventArgs (i.e., UpdateEventArgs), write another class to wrap the object providing the Update event, give the wrapper class its own Update event that is an EventHandler<UpdateEventArgs>, and get an IObservable<UpdateEventArgs> from that. But that's an annoying amount of work. Is there some way to create an IObservable<[something]> from a "non-standard" event like this, or am I out of luck?

  Read the article

• std::conditional compile-time branch evaluation

  - by cmannett85

  Compiling this: template < class T, class Y, class ...Args > struct isSame { static constexpr bool value = std::conditional< sizeof...( Args ), typename std::conditional< std::is_same< T, Y >::value, isSame< Y, Args... >, // Error! std::false_type >::type, std::is_same< T, Y > >::type::value; }; int main() { qDebug() << isSame< double, int >::value; return EXIT_SUCCESS; } Gives me this compiler error: error: wrong number of template arguments (1, should be 2 or more) The issue is that isSame< double, int > has an empty Args parameter pack, so isSame< Y, Args... > effectively becomes isSame< Y > which does not match the signature. But my question is: Why is that branch being evaluated at all? sizeof...( Args ) is false, so the inner std:conditional should not be evaluated. This isn't a runtime piece of code, the compiler knows that sizeof..( Args ) will never be true with the given template types. If you're curious, it's supposed to be a variadic version of std::is_same, not that it works...

  Read the article

• Security header is not valid - using curl php

  - by toni

  Hi all, Im implementing the Express Checkout, Paypal API using PHP. I have no problem with the first step:SetExpressCheckout. I a have awk=success. But in method GetExpressCheckout I get "Security header is not valid". I try to figure out the problem and i think found out maybe it was the curl not working well.. What i did i copy the whole URL: https://api-3t.sandbox.paypal.com/nvp?USER=sanbox_1276609583_biz_api1.gmail.com&PWD=1276609589&SIGNATURE=AYVosblmD7khKkvvb.bNxvFT0OQ2A8GopwByEuC.CfMHt65VaUmvAEy-&VERSION=62.0&token=EC-3YG18670X88588437&METHOD=GetExpressCheckoutDetails and paste it to the browser. This will result to: TOKEN=EC%2d3YG18670X88588437&CHECKOUTSTATUS=PaymentActionNotInitiated&TIMESTAMP=2010%2d06%2d16T07%3a40%3a12Z&CORRELATIONID=e1a1e469bf066&ACK=Success&VERSION=62%2e0&BUILD=1356926... But when that url executed in the function I made it will not work. Below is my function: function mycurl($url,$querystr){ $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_VERBOSE, 1); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); curl_setopt($ch, CURLOPT_POST, 1); curl_setopt($ch, CURLOPT_POSTFIELDS, $querystr); curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); $response = curl_exec($ch); curl_close ($ch); return $response; } I hope somebody can help on this. thanks so much. Note: - I Used the sandbox for this. I created a sandbox account, I have a Business account to represent a merchant, and a Personal account to represent a buyer. And I used this: endpoint url: api-3t.sandbox.paypal.com/nvp sandbox url: www.sandbox.paypal.com/cgi-bin/webscr This should not be the issue.

  Read the article

• Multiple generic parameters on a html helper extension method

  - by WestDiscGolf

  What I'm trying to do is create an extension method for the HtmlHelper to create a specific output and associated details like TextBoxFor<. What I want to do is specify the property from the model class as per TextBoxFor<, then an associated controller action and other parameters. So far the signature of the method looks like: public static MvcHtmlString Create<TModel, TProperty, TController>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Expression<Action<TController>> action, object htmlAttributes) where TController : Controller where TModel : class The issue occurs when I go to call it. In my view if I call it as per the TextBoxFor without specifying the Model type I am able to specify the lambda expression to set the property which it's for, but when I go to specify the action I am unable to. However, when I specify the controller type Html.Create<HomeController>( ... ) I am unable to specify the model property that the control is to be created for. I want to be able to call it like <%= Html.Create(x => x.Title, controller => controller.action, null) %> I've been hitting my head for a few hours now on this issue over the past day, can anyone point me in the right direction?

  Read the article

• Using an SHA1 with Micrsoft CAPI

  - by Erik Jõgi

  Hello, I have an SHA1 hash and I need to sign it. The CryptSignHash() method requires a HCRYPTHASH handle for signing. I create it and as I have the actual hash value already then set it: CryptCreateHash(cryptoProvider, CALG_SHA1, 0, 0, &hash); CryptSetHashParam(hash, HP_HASHVAL, hashBytes, 0); The hashBytes is an array of 20 bytes. However the problem is that the signature produced from this HCRYPTHASH handle is incorrect. I traced the problem down to the fact that CAPI actually doesn't use all 20 bytes from my hashBytes array. For some reason it thinks that SHA1 is only 4 bytes. To verify this I wrote this small program: HCRYPTPROV cryptoProvider; CryptAcquireContext(&cryptoProvider, NULL, NULL, PROV_RSA_FULL, 0); HCRYPTHASH hash; HCRYPTKEY keyForHash; CryptCreateHash(cryptoProvider, CALG_SHA1, keyForHash, 0, &hash); DWORD hashLength; CryptGetHashParam(hash, HP_HASHSIZE, NULL, &hashLength, 0); printf("hashLength: %d\n", hashLength); And this prints out hashLength: 4 ! Can anyone explain what I am doing wrong or why Microsoft CAPI thinks that SHA1 is 4 bytes (32 bits) instead of 20 bytes (160 bits). Thank you.

  Read the article

• Having some fun - what is a good way to include a secret key functionality and fire the KeyDown event?

  - by Sisyphus

  To keep myself interested, I try to put little Easter Eggs in my projects (mostly to amuse myself). I've seen some websites where you can type a series of letters "aswzaswz" and you get a "secret function" - how would I achieve this in C#? I've assigned a "secret function" in the past by using modifier keys bool showFunThing = (Control.ModifierKeys & Keys.Control) == Keys.Control; but wanted to get a bit more secretive (without the modifier keys) I just wanted the form to detect a certain word typed without any input ... I've built a method that I think should do it: private StringBuilder _pressedKeys = new StringBuilder(); protected override void OnKeyDown(KeyEventArgs e) { const string kWord = "fun"; char letter = (char)e.KeyValue; if (!char.IsLetterOrDigit(letter)) { return; } _pressedKeys.Append(letter); if (_pressedKeys.Length == kWord.Length) { if (_pressedKeys.ToString().ToLower() == kWord) { MessageBox.Show("Fun"); _pressedKeys.Clear(); } } base.OnKeyDown(e); } Now I need to wire it up but I can't figure out how I'm supposed to raise the event in the form designer ... I've tried this: this.KeyDown +=new System.Windows.Forms.KeyEventHandler(OnKeyDown); and a couple of variations on this but I'm missing something because it won't fire (or compile). It tells me that the OnKeyDown method is expecting a certain signature but I've got other methods like this where I haven't specified arguments. I fear that I may have got myself confused so I am turning to SO for help ... anyone?

  Read the article

• Can Win32_NetworkAdapterConfiguration.EnableStatic() be used to set more than one IP address?

  - by Andrew J. Brehm

  I ran into this problem in a Visual Basic program that uses WMI but could confirm it in PowerShell. Apparently the EnableStatic() method can only be used to set one IP address, despite taking two parameters IP address(es) and subnetmask(s) that are arrays. I.e. $a=get-wmiobject win32_networkadapterconfiguration -computername myserver This gets me an array of all network adapters on "myserver". After selecting a specific one ($a=$a[14] in this case), I can run $a.EnableStatic() which has this signature System.Management.ManagementBaseObject EnableStatic(System.String[] IPAddress, System.String[] SubnetMask) I thought this implies that I could set several IP addresses like this: $ips="192.168.1.42","192.168.1.43" $a.EnableStatic($ips,"255.255.255.0") But this call fails. However, this call works: $a.EnableStatic($ips[0],"255.255.255.0") It looks to me as if EnableStatic() really takes two strings rather than two arrays of strings as parameters. In Visual Basic it's more complicated and arrays must be passed but the method appears to take into account only the first element of each array. Am I confused again or is there some logic here?

  Read the article

• Setting minOccurs="0" (not required) on web service parameters of type int

  - by Alex Angas

  I have an ASP.NET 2.0 web method with the following signature: [WebMethod] public QueryResult[] GetListData( string url, string list, string query, int noOfItems, string titleField) I'm running the disco.exe tool to generate .wsdl and .disco files from this web service for use in SharePoint. The following WSDL for the parameters is being generated: <s:element minOccurs="0" maxOccurs="1" name="url" type="s:string" /> <s:element minOccurs="0" maxOccurs="1" name="list" type="s:string" /> <s:element minOccurs="0" maxOccurs="1" name="query" type="s:string" /> <s:element minOccurs="1" maxOccurs="1" name="noOfItems" type="s:int" /> <s:element minOccurs="0" maxOccurs="1" name="titleField" type="s:string" /> Why does the int parameter have minOccurs set to 1 instead of 0 and how do I change it? I've tried the following without success: [XmlElementAttribute(IsNullable=false)] in the parameter declaration: makes no difference (as expected when you think about it) [XmlElementAttribute(IsNullable=true)] in the parameter declaration: gives error "IsNullable may not be 'true' for value type System.Int32. Please consider using Nullable instead." changing the parameter type to int? : keeps minOccurs="1" and adds nillable="true" [XmlIgnore] in the parameter declaration: the parameter is never output to the WSDL at all

  Read the article

• Does it ever make sense to make a fundamental (non-pointer) parameter const?

  - by Scott Smith

  I recently had an exchange with another C++ developer about the following use of const: void Foo(const int bar); He felt that using const in this way was good practice. I argued that it does nothing for the caller of the function (since a copy of the argument was going to be passed, there is no additional guarantee of safety with regard to overwrite). In addition, doing this prevents the implementer of Foo from modifying their private copy of the argument. So, it both mandates and advertises an implementation detail. Not the end of the world, but certainly not something to be recommended as good practice. I'm curious as to what others think on this issue. Edit: OK, I didn't realize that const-ness of the arguments didn't factor into the signature of the function. So, it is possible to mark the arguments as const in the implementation (.cpp), and not in the header (.h) - and the compiler is fine with that. That being the case, I guess the policy should be the same for making local variables const. One could make the argument that having different looking signatures in the header and source file would confuse others (as it would have confused me). While I try to follow the Principle of Least Astonishment with whatever I write, I guess it's reasonable to expect developers to recognize this as legal and useful.

  Read the article

• How do I add code automatically to a derived function in C++

  - by Ian

  I have code that's meant to manage operations on both a networked client and a server, since there is significant overlap between the two. However, there are a few functions here and there that are meant to be exclusively called by the client or server, and accidentally calling a client function on the server (or vice versa) is a significant source of bugs. To reduce these sorts of programming errors, I'm trying to tag functions so that they'll raise a ruckus if they're misused. My current solution is a simple macro at the start of each function that calls an assert if the client or server accesses members they shouldn't. However, this runs into problems when there are multiple derived instances of classes, in that I have to tag the implementation as client or server side in EVERY child class. What I'd like to be able to do is put a tag in the virtual member's signature in the base class, so that I only have to tag it once and not run into errors by forgetting to do it repeatedly. I've considered putting a check in a base class implementation and then referring to it with something like base::functionName, but that runs into the same issue as far as needing to manually add the function call to every implementation. Ideally, I'd be able to have parent versions of the function called automatically like default constructors do. Does anybody know how to achieve something like this in C++? Is there an alternate approach I should be considering? Thanks!

  Read the article

• Slope requires a real as parameter 2?

  - by Dave Jarvis

  Question How do you pass the correct value to udf_slope's second parameter type? Attempts CAST(Y.YEAR AS FLOAT), but that failed (SQL error). Y.YEAR + 0.0, but that failed, too (see error message). slope(D.AMOUNT, 1.0), failed as well Error Message Using udf_slope fails due to: Can't initialize function 'slope'; slope() requires a real as parameter 2 Code SELECT D.AMOUNT, Y.YEAR, slope(D.AMOUNT, Y.YEAR + 0.0) as SLOPE, intercept(D.AMOUNT, Y.YEAR + 0.0) as INTERCEPT FROM YEAR_REF Y, DAILY D Here, D.AMOUNT is a FLOAT and Y.YEAR is an INTEGER. Create Function The slope function was created as follows: CREATE AGGREGATE FUNCTION slope RETURNS REAL SONAME 'udf_slope.so'; Function Signature From udf_slope.cc: double slope( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* is_error ) Example Usages Reading the fine manual reveals: UDF intercept() Calculates the intercept of the linear regression of two sets of variables. Function name intercept Input parameter(s) 2 (dependent variable: REAL, independent variable: REAL) Examples SELECT intercept(income,age) FROM customers UDF slope() Calculates the slope of the linear regression of two sets of variables. Function name slope Input parameter(s) 2 (dependent variable: REAL, independent variable: REAL) Examples SELECT slope(income,age) FROM customers Thoughts? Thank you!

  Read the article

• Is there anything bad in declaring static inner class inside interface in java?

  - by Roman

  I have an interface ProductService with method findByCriteria. This method had a long list of nullable parameters, like productName, maxCost, minCost, producer and so on. I refactored this method by introducing Parameter Object. I created class SearchCriteria and now method signature looks like this: findByCriteria (SearchCriteria criteria) I thought that instances of SearchCriteria are only created by method callers and are only used inside findByCriteria method, i.e.: void processRequest() { SearchCriteria criteria = new SearchCriteria () .withMaxCost (maxCost) ....... .withProducer (producer); List<Product> products = productService.findByCriteria (criteria); .... } and List<Product> findByCriteria(SearchCriteria criteria) { return doSmthAndReturnResult(criteria.getMaxCost(), criteria.getProducer()); } So I did not want to create separate public class for SearchCriteria and put it inside ProductServiceInterface: public interface ProductService { List<Product> findByCriteria (SearchCriteria criteria); static class SearchCriteria { ... } } Is there anything bad in this interface? Where whould you place SearchCriteria class?

  Read the article

• Reverse reading WORD from a binary file?

  - by Angel

  Hi, I have a structure: struct JFIF_HEADER { WORD marker[2]; // = 0xFFD8FFE0 WORD length; // = 0x0010 BYTE signature[5]; // = "JFIF\0" BYTE versionhi; // = 1 BYTE versionlo; // = 1 BYTE xyunits; // = 0 WORD xdensity; // = 1 WORD ydensity; // = 1 BYTE thumbnwidth; // = 0 BYTE thumbnheight; // = 0 }; This is how I read it from the file: HANDLE file = CreateFile(filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); DWORD tmp = 0; DWORD size = GetFileSize(file, &tmp); BYTE *DATA = new BYTE[size]; ReadFile(file, DATA, size, &tmp, 0); JFIF_HEADER header; memcpy(&header, DATA, sizeof(JFIF_HEADER)); This is how the beginning of my file looks in hex editor: 0xFF 0xD8 0xFF 0xE0 0x00 0x10 0x4A 0x46 0x49 0x46 0x00 0x01 0x01 0x00 0x00 0x01 When I print header.marker, it shows exactly what it should (0xFFD8FFE0). But when I print header.length, it shows 0x1000 instead of 0x0010. The same thing is with xdensity and ydensity. Why do I get wrong data when reading a WORD? Thank you.

  Read the article

• How to store and remove dynamically and automatic variable of generic data type in custum list data

  - by Vineel Kumar Reddy

  Hi I have created a List data structure implementation for generic data type with each node declared as following. struct Node { void *data; .... .... } So each node in my list will have pointer to the actual data(generic could be anything) item that should be stored in the list. I have following signature for adding a node to the list AddNode(struct List *list, void* eledata); the problem is when i want to remove a node i want to free even the data block pointed by *data pointer inside the node structure that is going to be freed. at first freeing of datablock seems to be straight forward free(data) // forget about the syntax..... But if data is pointing to a block created by malloc then the above call is fine....and we can free that block using free function int *x = (int*) malloc(sizeof(int)); *x = 10; AddNode(list,(void*)x); // x can be freed as it was created using malloc what if a node is created as following int x = 10; AddNode(list,(void*)&x); // x cannot be freed as it was not created using malloc Here we cannot call free on variable x!!!! How do i know or implement the functionality for both dynamically allocated variables and static ones....that are passed to my list.... Thanks in advance...

  Read the article

• Exceptional C++[Bug]?

  - by gautam kumar

  I have been reading Exceptional C++ by Herb Sutter. On reaching Item 32 I found the following namespace A { struct X; struct Y; void f( int ); void g( X ); } namespace B { void f( int i ) { f( i ); // which f()? } } This f() calls itself, with infinite recursion. The reason is that the only visible f() is B::f() itself. There is another function with signature f(int), namely the one in namespace A. If B had written "using namespace A;" or "using A::f;", then A::f(int) would have been visible as a candidate when looking up f(int), and the f(i) call would have been ambiguous between A::f(int) and B::f(int). Since B did not bring A::f(int) into scope, however, only B::f(int) can be considered, so the call unambiguously resolves to B::f(int). But when I did the following.. namespace A { struct X; struct Y; void f( int ); void g( X ); } namespace B { using namespace A; void f( int i ) { f( i ); // No error, why? } } That means Herb Sutter has got it all wrong? If not why dont I get an error?

  Read the article

< Previous Page | 98 99 100 101 102 103 104 105 106 107 108 109  | Next Page >