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  • how to copy char * into a string and vice-versa

    - by user295030
    If i pass a char * into a function. I want to then take that char * convert it to a std::string and once I get my result convert it back to char * from a std::string to show the result. I don't know how to do this for conversion ( I am not talking const char * but just char *) I am not sure how to manipulate the value of the pointer I send in. so steps i need to do take in a char * convert it into a string. take the result of that string and put it back in the form of a char * return the result such that the value should be available outside the function and not get destroyed. If possible can i see how it could be done via reference vs a pointer (whose address I pass in by value however I can still modify the value that pointer is pointing to. so even though the copy of the pointer address in the function gets destroyed i still see the changed value outside. thanks!

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  • Wierdness debugging Visual Studio C++ 2008

    - by Jeff Dege
    I have a legacy C++ app, that in its most incarnation we've been building with makefiles and VS2003's command-line tool. I'm trying to get it to build using VS2008 and MsBuild. The build is working OK, but I'm getting errors where I'd never seen errors, before, and stepping through in VS2008's debugger only confuses me. The app links a number of static libraries, which fall into two categories: those that are part of the same application suite, and those that are shared between a number of application suites. Originally, I had a .csproj file for each static library, and two .sln files, one for the application suite (including the suite-specific libraries) and one for the non-suite-specific shared libraries. The shared libraries were included in the link, their projects were not included in the application suite .sln. The application instantiates an object from a class that is defined in one of the shared libraries. The class has a member object of a class that wraps a linked list. The constructor of the linked list class sets its "head" pointer to null. When I run the app, and try to add an element to the linked list, I get an error - the head pointer contains the value 0xCCCCCCCC. So I step through with the debugger. And see weirdness. When the current line in the debugger is in a source file belonging to the static library, the head pointer contains 0x00000000. When I step into the constructor, I can see the pointer being set to that value, and when I'm stepped into any other method of the class, I can see that the head pointer still contains 0x00000000. But when I step out into methods that are defined in the application suite .sln, it contains 0xCCCCCCCC. It's not like it's being overwritten. It changes back and forth depending upon which source file I am currently debugging. So I included the shared library's project in the application suite .sln, and now I see the head pointer containing 0xCCCCCCCC all the time. It looks like the constructor of the linked list class is not being called. So now, I'm entirely confused. Anyone have any ideas?

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  • Getting list of all existing vtables.

    - by Patrick
    In my application I have quite some void-pointers (this is because of historical reasons, application was originally written in pure C). In one of my modules I know that the void-pointers points to instances of classes that could inherit from a known base class, but I cannot be 100% sure of it. Therefore, doing a dynamic_cast on the void-pointer might give problems. Possibly, the void-pointer even points to a plain-struct (so no vptr in the struct). I would like to investigate the first 4 bytes of the memory the void-pointer is pointing to, to see if this is the address of the valid vtable. I know this is platform, maybe even compiler-version-specific, but it could help me in moving the application forward, and getting rid of all the void-pointers over a limited time period (let's say 3 years). Is there a way to get a list of all vtables in the application, or a way to check whether a pointer points to a valid vtable, and whether that instance pointing to the vtable inherits from a known base class?

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  • C -- Basic Struct questions

    - by Ryan Yu
    So I'm trying to learn C right now, and I have some basic struct questions I'd like to clear up: Basically, everything centers around this snippet of code: #include <stdio.h> #include <stdlib.h> #define MAX_NAME_LEN 127 typedef struct { char name[MAX_NAME_LEN + 1]; unsigned long sid; } Student; /* return the name of student s */ const char* getName (const Student* s) { // the parameter 's' is a pointer to a Student struct return s->name; // returns the 'name' member of a Student struct } /* set the name of student s If name is too long, cut off characters after the maximum number of characters allowed. */ void setName(Student* s, const char* name) { // 's' is a pointer to a Student struct | 'name' is a pointer to the first element of a char array (repres. a string) s->name = name; } /* return the SID of student s */ unsigned long getStudentID(const Student* s) { // 's' is a pointer to a Student struct return s->sid; } /* set the SID of student s */ void setStudentID(Student* s, unsigned long sid) { // 's' is a pointer to a Student struct | 'sid' is a 'long' representing the desired SID s->sid = sid; } I've commented up the code in an attempt to solidify my understanding of pointers; I hope they're all accurate. So anyway, I have a feeling that setName and setStudentID aren't correct, but I'm not exactly sure why. Can someone explain? Thanks!

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  • Decayed multidimensional array return from function

    - by paul simmons
    related to http://stackoverflow.com/questions/2520535/gcc-multi-dim-array-or-double-pointer-for-warning-free-compile , is there a way to return so-called "decayed array pointer" from a function? in summary (suppose 2 dim array) returning int (*a)[5] format rather than int** format? as far as I see, when returned int** pointer is sent to another function waiting (int*)[] parameter, it is not working correctly.

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  • Useless variable name in C struct type definition

    - by user1210233
    I'm implementing a linked list in C. Here's a struct that I made, which represents the linked list: typedef struct llist { struct lnode* head; /* Head pointer either points to a node with data or NULL */ struct lnode* tail; /* Tail pointer either points to a node with data or NULL */ unsigned int size; /* Size of the linked list */ } list; Isn't the "llist" basically useless. When a client uses this library and makes a new linked list, he would have the following declaration: list myList; So typing llist just before the opening brace is practically useless, right? The following code basically does the same job: typedef struct { struct lnode* head; /* Head pointer either points to a node with data or NULL */ struct lnode* tail; /* Tail pointer either points to a node with data or NULL */ unsigned int size; /* Size of the linked list */ } list;

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  • Could I ever want to access the address zero?

    - by Joel
    The constant 0 is used as the null pointer in C and C++. But as in http://stackoverflow.com/questions/2389251/pointer-to-a-specific-fixed-address there seems to be some possible use of assigning fixed addresses. Is there ever any conceivable need, in any system, for whatever low level task, for accessing the address 0? If there is, how is that solved with 0 being the null pointer and all? If not, what makes it certain that there is not such a need?

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  • sending address of a variable declared on the stack?

    - by kobac
    I have a doubt concerning declaring variables, their scope, and if their address could be sent to other functions even if they are declared on the stack? class A{ AA a; void f1(){ B b; aa.f2(&b); } }; class AA{ B* mb; f2(B* b){ mb = b; //... } }; Afterwards, I use my AA::mb pointer in the code. So things I would like to know are following. When the program exits A::f1() function, b variable since declared as a local variable and placed on the stack, can't be used anymore afterwards. What happens with the validity of the AA::mb pointer? It contains the address of the local variable which could not be available anymore, so the pointer isn't valid anymore? If B class is a std::<vector>, and AA::mb is not a pointer anymore to that vector, but a vector collection itself for example. I would like to avoid copying all of it's contents in AA::f2() to a member AA::mb in line mb = b. Which solution would you recommend since I can't assign a pointer to it, because it'll be destroyed when the program exits AA::f2()

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  • walking list in KDB/kernel debugger

    - by user291849
    I need to walk a link list in the kernel debugger. How can I determine the head pointer and walk the list? I have a listing and can find the address and location in the code where I check to see if I have a head, so I know the specific code location and address. But not sure how to determine the pointer or how to determine the next element and pointer on the list.

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  • Linked List manipulation, issues retrieving data c++

    - by floatfil
    I'm trying to implement some functions to manipulate a linked list. The implementation is a template typename T and the class is 'List' which includes a 'head' pointer and also a struct: struct Node { // the node in a linked list T* data; // pointer to actual data, operations in T Node* next; // pointer to a Node }; Since it is a template, and 'T' can be any data, how do I go about checking the data of a list to see if it matches the data input into the function? The function is called 'retrieve' and takes two parameters, the data and a pointer: bool retrieve(T target, T*& ptr); // This is the prototype we need to use for the project "bool retrieve : similar to remove, but not removed from list. If there are duplicates in the list, the first one encountered is retrieved. Second parameter is unreliable if return value is false. E.g., " Employee target("duck", "donald"); success = company1.retrieve(target, oneEmployee); if (success) { cout << "Found in list: " << *oneEmployee << endl; } And the function is called like this: company4.retrieve(emp3, oneEmployee) So that when you cout *oneEmployee, you'll get the data of that pointer (in this case the data is of type Employee). (Also, this is assuming all data types have the apropriate overloaded operators) I hope this makes sense so far, but my issue is in comparing the data in the parameter and the data while going through the list. (The data types that we use all include overloads for equality operators, so oneData == twoData is valid) This is what I have so far: template <typename T> bool List<T>::retrieve(T target , T*& ptr) { List<T>::Node* dummyPtr = head; // point dummy pointer to what the list's head points to for(;;) { if (*dummyPtr->data == target) { // EDIT: it now compiles, but it breaks here and I get an Access Violation error. ptr = dummyPtr->data; // set the parameter pointer to the dummy pointer return true; // return true } else { dummyPtr = dummyPtr->next; // else, move to the next data node } } return false; } Here is the implementation for the Employee class: //-------------------------- constructor ----------------------------------- Employee::Employee(string last, string first, int id, int sal) { idNumber = (id >= 0 && id <= MAXID? id : -1); salary = (sal >= 0 ? sal : -1); lastName = last; firstName = first; } //-------------------------- destructor ------------------------------------ // Needed so that memory for strings is properly deallocated Employee::~Employee() { } //---------------------- copy constructor ----------------------------------- Employee::Employee(const Employee& E) { lastName = E.lastName; firstName = E.firstName; idNumber = E.idNumber; salary = E.salary; } //-------------------------- operator= --------------------------------------- Employee& Employee::operator=(const Employee& E) { if (&E != this) { idNumber = E.idNumber; salary = E.salary; lastName = E.lastName; firstName = E.firstName; } return *this; } //----------------------------- setData ------------------------------------ // set data from file bool Employee::setData(ifstream& inFile) { inFile >> lastName >> firstName >> idNumber >> salary; return idNumber >= 0 && idNumber <= MAXID && salary >= 0; } //------------------------------- < ---------------------------------------- // < defined by value of name bool Employee::operator<(const Employee& E) const { return lastName < E.lastName || (lastName == E.lastName && firstName < E.firstName); } //------------------------------- <= ---------------------------------------- // < defined by value of inamedNumber bool Employee::operator<=(const Employee& E) const { return *this < E || *this == E; } //------------------------------- > ---------------------------------------- // > defined by value of name bool Employee::operator>(const Employee& E) const { return lastName > E.lastName || (lastName == E.lastName && firstName > E.firstName); } //------------------------------- >= ---------------------------------------- // < defined by value of name bool Employee::operator>=(const Employee& E) const { return *this > E || *this == E; } //----------------- operator == (equality) ---------------- // if name of calling and passed object are equal, // return true, otherwise false // bool Employee::operator==(const Employee& E) const { return lastName == E.lastName && firstName == E.firstName; } //----------------- operator != (inequality) ---------------- // return opposite value of operator== bool Employee::operator!=(const Employee& E) const { return !(*this == E); } //------------------------------- << --------------------------------------- // display Employee object ostream& operator<<(ostream& output, const Employee& E) { output << setw(4) << E.idNumber << setw(7) << E.salary << " " << E.lastName << " " << E.firstName << endl; return output; } I will include a check for NULL pointer but I just want to get this working and will test it on a list that includes the data I am checking. Thanks to whoever can help and as usual, this is for a course so I don't expect or want the answer, but any tips as to what might be going wrong will help immensely!

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  • gluNewQuadric() before opengl's initialization

    - by Schrödinger's cat
    Hello, I'm working on a c++ code that uses SDL/opengl. Is this possible to create a pointer to a quadric with 'gluNewQuadric()' before having initialized opengl with 'SDL_SetVideoMode'? The idea is to create a class with a (pointer to a) quadric class member that has to be instantiate before the 'SDL_SetVideoMode' call. This pointer is initialized in the class' constructor with a 'gluNewQuadric()' call.

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  • Using `g_object_set_data` for passing user name.

    - by PP
    I am using g_object_set_data to set user name with event_box so in call back i can get it with in event_box pointer. g_object_set_data(G_OBJECT(event_box), "user_name", (gpointer)(user_name) ); but problem is that i am setting user_name which is not an pointer allocated string. It is an local string (not allocated on hip) which gets destroyed. So is it necessary to allocated and then use the pointer, i just want to associate one name with this event_box.

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  • Java reference storage question

    - by aab
    In java, when you pass an object to a method as a parameter, it is actually passing a reference, or a pointer, to that object because objects in Java are references. Inside the function, it has a pointer to that object which is a location in memory. I am wondering where this pointer lives in memory? Is a new memory location created once inside the function to hold this reference?

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  • Modifying a gedit syntax highlighting file

    - by Oscar Saleta Reig
    I am trying to change a highlighting file from Gedit. I have modified the file /usr/share/gtksourceview-3.0/language-specs/fortran.lang because I want to change the cases in which the editor takes a statement as a comment. The problem I have is that when I choose the new highlighting scheme nothing highlights, it just remains as plain text. The file fortran.lang was opened with su permissions and I just copy-pasted everything into a new Gedit file and later saved it as fortran_enhanced.lang in the same folder. The changes I've done to the original file are these: Original fortran.lang file: <language id="fortran" _name="Fortran 95" version="2.0" _section="Sources"> <metadata> <property name="mimetypes">text/x-fortran</property> <property name="globs">*.f;*.f90;*.f95;*.for</property> <property name="line-comment-start">!</property> </metadata> <styles> <style id="comment" _name="Comment" map-to="def:comment"/> <style id="floating-point" _name="Floating Point" map-to="def:floating-point"/> <style id="keyword" _name="Keyword" map-to="def:keyword"/> <style id="intrinsic" _name="Intrinsic function" map-to="def:builtin"/> <style id="boz-literal" _name="BOZ Literal" map-to="def:base-n-integer"/> <style id="decimal" _name="Decimal" map-to="def:decimal"/> <style id="type" _name="Data Type" map-to="def:type"/> </styles> <default-regex-options case-sensitive="false"/> <definitions> <!-- Note: contains an hack to avoid considering ^COMMON a comment --> <context id="line-comment" style-ref="comment" end-at-line-end="true" class="comment" class-disabled="no-spell-check"> <start>!|(^[Cc](\b|[^OoAaYy]))</start> <include> <context ref="def:escape"/> <context ref="def:in-line-comment"/> </include> </context> (...) Modified fortran_enhanced.lang file: <!-- Note: changed language id and name --> <language id="fortran_enhanced" _name="Fortran 95 2.0" version="2.0" _section="Sources"> <metadata> <property name="mimetypes">text/x-fortran</property> <!-- Note: removed *.f and *.for from file extensions --> <property name="globs">*.f90;*.f95;</property> <property name="line-comment-start">!</property> </metadata> <styles> <style id="comment" _name="Comment" map-to="def:comment"/> <style id="floating-point" _name="Floating Point" map-to="def:floating-point"/> <style id="keyword" _name="Keyword" map-to="def:keyword"/> <style id="intrinsic" _name="Intrinsic function" map-to="def:builtin"/> <style id="boz-literal" _name="BOZ Literal" map-to="def:base-n-integer"/> <style id="decimal" _name="Decimal" map-to="def:decimal"/> <style id="type" _name="Data Type" map-to="def:type"/> </styles> <default-regex-options case-sensitive="false"/> <definitions> <!-- Note: I want comments only beginning with !, not C --> <context id="line-comment" style-ref="comment" end-at-line-end="true" class="comment" class-disabled="no-spell-check"> <start>!</start> <include> <context ref="def:escape"/> <context ref="def:in-line-comment"/> </include> </context> (...) I have read this question [ Custom gedit Syntax Highlighting for Dummies? ] and I tried to make the new fortran_enhanced.lang file readable with $ cd /usr/share/gtksourceview-3.0/language-specs $ sudo chmod 0644 fortran_enhanced.lang but it doesn't seem that made some difference. I have to say that I have never done a thing like this before and I don't even understand most of the language file, so I am open to every criticism, as I have been guided purely by intuition. Thank you in advanced!

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  • Excel - working in a bank

    - by Einsteins Grandson
    I am supposed to go to an interview to a bank for just supporting managers in projects. It's a part-time job and the thing is that bank uses Excel for everything. Modifications of tables of really lot of data... What can I expect to find in the test of Excel? I have some books that are around 1000 pages thick but I don't have time and also don't feel like reading everything that's in them. These are the books that I have: http://www.amazon.com/Excel-2010-Bible-John-Walkenbach/dp/0470474874/ref=sr_1_1?ie=UTF8&qid=1347571864&sr=8-1&keywords=excel+bible http://www.amazon.com/Excel-2010-The-Missing-Manual/dp/1449382355/ref=sr_1_1?ie=UTF8&qid=1347571884&sr=8-1&keywords=Excel+2010+The+Missing+Manual http://www.amazon.com/Microsoft-Excel-2010-In-Depth/dp/0789743086/ref=sr_1_1?ie=UTF8&qid=1347571904&sr=8-1&keywords=Microsoft+Excel+2010+In+Depth So, anybody knows a good online tutorial or a book that would contain the basics and was not that much thick? ;-) Thanks so much!!!

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  • Perf4j Not Logging Correctly

    - by Jehud
    I setup some stop watch calls in my code to measure some code blocks and all the messages are going into my primary log and not into the timing log. The perfStats.log file gets created just fine but all the messages go to the root log which I didn't think was supposed to happen according to the docs I've read. Is there something obvious I'm missing here? perf4j tutorial link: http://perf4j.codehaus.org/devguide.html#Using_the_log4j_Appenders_to_Generate_Real-Time_Performance_Information Example code import org.apache.log4j.Logger; import org.perf4j.LoggingStopWatch; import org.perf4j.StopWatch; public class PerfLogger { /** * @param args */ public static void main(String[] args) { Logger logger = Logger.getLogger(PerfLogger.class.getName()); logger.info("Starting perf log test"); StopWatch stopWatch = new LoggingStopWatch("test time"); try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } stopWatch.stop(); } } Example log4j.xml <log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'> <appender name="STDOUT-DEBUG" class="org.apache.log4j.ConsoleAppender"> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%d %-5p [%t]%x %M (%F:%L) - %m%n"/> </layout> </appender> <!-- Perf4J appenders --> <!-- This AsyncCoalescingStatisticsAppender groups StopWatch log messages into GroupedTimingStatistics messages which it sends on the file appender defined below --> <appender name="CoalescingStatistics" class="org.perf4j.log4j.AsyncCoalescingStatisticsAppender"> <!-- The TimeSlice option is used to determine the time window for which all received StopWatch logs are aggregated to create a single GroupedTimingStatistics log. Here we set it to 10 seconds, overriding the default of 30000 ms --> <param name="TimeSlice" value="10000"/> <appender-ref ref="fileAppender"/> </appender> <!-- This file appender is used to output aggregated performance statistics --> <appender name="fileAppender" class="org.apache.log4j.FileAppender"> <param name="File" value="perfStats.log"/> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%m%n"/> </layout> </appender> <!-- Loggers --> <!-- The Perf4J logger. Note that org.perf4j.TimingLogger is the value of the org.perf4j.StopWatch.DEFAULT_LOGGER_NAME constant. Also, note that additivity is set to false, which is usually what is desired - this means that timing statements will only be sent to this logger and NOT to upstream loggers. --> <logger name="org.perf4j.TimingLogger" additivity="false"> <level value="INFO"/> <appender-ref ref="CoalescingStatistics"/> </logger> <root> <priority value="info"/> <appender-ref ref="STDOUT-DEBUG"/> </root> </log4j:configuration>

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  • populate a tree view with an xml file

    - by syedsaleemss
    Im using .net windows form application. I have an xml file.I want to populate a tree view with data from a xml file. I am doing this using the following code. private void button1_Click(object sender, EventArgs e) { try { this.Cursor = System.Windows.Forms.Cursors.WaitCursor; //string strXPath = "languages"; string strRootNode = "Treeview Sample"; OpenFileDialog Dlg = new OpenFileDialog(); Dlg.Filter = "All files(*.*)|*.*|xml file (*.xml)|*.txt"; Dlg.CheckFileExists = true; string xmlfilename = ""; if (Dlg.ShowDialog() == DialogResult.OK) { xmlfilename = Dlg.FileName; } // Load the XML file. //XmlDocument dom = new XmlDocument(); //dom.Load(xmlfilename); XmlDocument doc = new XmlDocument(); doc.Load(xmlfilename); string rootName = doc.SelectSingleNode("/*").Name; textBox4.Text = rootName.ToString(); //XmlNode root = dom.LastChild; //textBox4.Text = root.Name.ToString(); // Load the XML into the TreeView. this.treeView1.Nodes.Clear(); this.treeView1.Nodes.Add(new TreeNode(strRootNode)); TreeNode tNode = new TreeNode(); tNode = this.treeView1.Nodes[0]; XmlNodeList oNodes = doc.SelectNodes(textBox4.Text); XmlNode xNode = oNodes.Item(0).ParentNode; AddNode(ref xNode, ref tNode); this.treeView1.CollapseAll(); this.treeView1.Nodes[0].Expand(); this.Cursor = System.Windows.Forms.Cursors.Default; } catch (Exception ex) { this.Cursor = System.Windows.Forms.Cursors.Default; MessageBox.Show(ex.Message, "Error"); } } private void AddNode(ref XmlNode inXmlNode, ref TreeNode inTreeNode) { // Recursive routine to walk the XML DOM and add its nodes to a TreeView. XmlNode xNode; TreeNode tNode; XmlNodeList nodeList; int i; // Loop through the XML nodes until the leaf is reached. // Add the nodes to the TreeView during the looping process. if (inXmlNode.HasChildNodes) { nodeList = inXmlNode.ChildNodes; for (i = 0; i <= nodeList.Count - 1; i++) { xNode = inXmlNode.ChildNodes[i]; inTreeNode.Nodes.Add(new TreeNode(xNode.Name)); tNode = inTreeNode.Nodes[i]; AddNode(ref xNode, ref tNode); } } else { inTreeNode.Text = inXmlNode.OuterXml.Trim(); } } My xml file is this:"hello.xml" - - abc hello how ru - def i m fine - ghi how abt u Now after using the above code I am able to populate the tree view. But I dont like to populate the complete xml file. I should get only till languages language key value I don't want abc how are you etc..... I mean to say the leaf nodes. Please help me

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  • C++ template function specialization using TCHAR on Visual Studio 2005

    - by Eli
    I'm writing a logging class that uses a templatized operator<< function. I'm specializing the template function on wide-character string so that I can do some wide-to-narrow translation before writing the log message. I can't get TCHAR to work properly - it doesn't use the specialization. Ideas? Here's the pertinent code: // Log.h header class Log { public: template <typename T> Log& operator<<( const T& x ); template <typename T> Log& operator<<( const T* x ); template <typename T> Log& operator<<( const T*& x ); ... } template <typename T> Log& Log::operator<<( const T& input ) { printf("ref"); } template <typename T> Log& Log::operator<<( const T* input ) { printf("ptr"); } template <> Log& Log::operator<<( const std::wstring& input ); template <> Log& Log::operator<<( const wchar_t* input ); And the source file // Log.cpp template <> Log& Log::operator<<( const std::wstring& input ) { printf("wstring ref"); } template <> Log& Log::operator<<( const wchar_t* input ) { printf("wchar_t ptr"); } template <> Log& Log::operator<<( const TCHAR*& input ) { printf("tchar ptr ref"); } Now, I use the following test program to exercise these functions // main.cpp - test program int main() { Log log; log << "test 1"; log << L"test 2"; std::string test3( "test3" ); log << test3; std::wstring test4( L"test4" ); log << test4; TCHAR* test5 = L"test5"; log << test4; } Running the above tests reveals the following: // Test results ptr wchar_t ptr ref wstring ref ref Unfortunately, that's not quite right. I'd really like the last one to be "TCHAR", so that I can convert it. According to Visual Studio's debugger, the when I step in to the function being called in test 5, the type is wchar_t*& - but it's not calling the appropriate specialization. Ideas? I'm not sure if it's pertinent or not, but this is on a Windows CE 5.0 device.

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  • Choosing a type for search results in C#

    - by Chris M
    I have a result set that will never exceed 500; the results that come back from the web-service are assigned to a search results object. The data from the webservice is about 2mb; the bit I want to use is about a third of each record, so this allows me to cache and quickly manipulate it. I want to be able to sort and filter the results with the least amount of overhead and as fast as possible so I used the VCSKICKS timing class to measure their performance Average Total (10,000) Type Create Sort Create Sort HashSet 0.1579 0.0003 1579 3 IList 0.0633 0.0002 633 2 IQueryable 0.0072 0.0432 72 432 Measured in Seconds using http://www.vcskicks.com/algorithm-performance.php I created the hashset through a for loop over the web-service response (adding to the hashset). The List & IQueryable were created using LINQ. Question I can understand why HashSet takes longer to create (the foreach loop vs linq); but why would IQueryable take longer to sort than the other two; and finally is there a better way to assign the HashSet. Thanks Actual Program public class Program { private static AuthenticationHeader _authHeader; private static OPSoapClient _opSession; private static AccommodationSearchResponse _searchResults; private static HashSet<SearchResults> _myHash; private static IList<SearchResults> _myList; private static IQueryable<SearchResults> _myIQuery; static void Main(string[] args) { #region Setup WebService _authHeader = new AuthenticationHeader { UserName = "xx", Password = "xx" }; _opSession = new OPSoapClient(); #region Setup Search Results _searchResults = _opgSession.SearchCR(_authHeader, "ENG", "GBP", "GBR"); #endregion Setup Search Results #endregion Setup WebService // HASHSET SpeedTester hashTest = new SpeedTester(TestHashSet); hashTest.RunTest(); Console.WriteLine("- Hash Test \nAverage Running Time: {0}; Total Time: {1}", hashTest.AverageRunningTime, hashTest.TotalRunningTime); SpeedTester hashSortTest = new SpeedTester(TestSortingHashSet); hashSortTest.RunTest(); Console.WriteLine("- Hash Sort Test \nAverage Running Time: {0}; Total Time: {1}", hashSortTest.AverageRunningTime, hashSortTest.TotalRunningTime); // ILIST SpeedTester listTest = new SpeedTester(TestList); listTest.RunTest(); Console.WriteLine("- List Test \nAverage Running Time: {0}; Total Time: {1}", listTest.AverageRunningTime, listTest.TotalRunningTime); SpeedTester listSortTest = new SpeedTester(TestSortingList); listSortTest.RunTest(); Console.WriteLine("- List Sort Test \nAverage Running Time: {0}; Total Time: {1}", listSortTest.AverageRunningTime, listSortTest.TotalRunningTime); // IQUERIABLE SpeedTester iqueryTest = new SpeedTester(TestIQueriable); iqueryTest.RunTest(); Console.WriteLine("- iquery Test \nAverage Running Time: {0}; Total Time: {1}", iqueryTest.AverageRunningTime, iqueryTest.TotalRunningTime); SpeedTester iquerySortTest = new SpeedTester(TestSortableIQueriable); iquerySortTest.RunTest(); Console.WriteLine("- iquery Sort Test \nAverage Running Time: {0}; Total Time: {1}", iquerySortTest.AverageRunningTime, iquerySortTest.TotalRunningTime); } static void TestHashSet() { var test = _searchResults.Items; _myHash = new HashSet<SearchResults>(); foreach(var x in test) { _myHash.Add(new SearchResults { Ref = x.Ref, Price = x.StandardPrice }); } } static void TestSortingHashSet() { var sorted = _myHash.OrderBy(s => s.Price); } static void TestList() { var test = _searchResults.Items; _myList = (from x in test select new SearchResults { Ref = x.Ref, Price = x.StandardPrice }).ToList(); } static void TestSortingList() { var sorted = _myList.OrderBy(s => s.Price); } static void TestIQueriable() { var test = _searchResults.Items; _myIQuery = (from x in test select new SearchResults { Ref = x.Ref, Price = x.StandardPrice }).AsQueryable(); } static void TestSortableIQueriable() { var sorted = _myIQuery.OrderBy(s => s.Price); } }

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  • How to prevent PHP variables from being arrays or objects?

    - by MJB
    I think that (the title) is the problem I am having. I set up a MySQL connection, I read an XML file, and then I insert those values into a table by looping through the elements. The problem is, instead of inserting only 1 record, sometimes I insert 2 or 3 or 4. It seems to depend on the previous values I have read. I think I am reinitializing the variables, but I guess I am missing something -- hopefully something simple. Here is my code. I originally had about 20 columns, but I shortened the included version to make it easier to read. $ctr = 0; $sql = "insert into csd (id,type,nickname,hostname,username,password) ". "values (?,?,?,?,?,?)"; $cur = $db->prepare($sql); for ($ctr = 0; $ctr < $expected_count; $ctr++) { unset($bind_vars,$dat); $lbl = "csd_{$ctr}"; $dat['type'] = (string) $ref->itm->csds->$lbl->type; $dat['nickname'] = (string) $ref->itm->csds->$lbl->nickname; $dat['hostname'] = (string) $ref->itm->csds->$lbl->hostname; $dat['username'] = (string) $ref->itm->csds->$lbl->username; $dat['password'] = (string) $ref->itm->csds->$lbl->password; $bind_vars = array( $id,$dat['$type'], $dat['$nickname'], $dat['$hostname'], $dat['$username'], $dat['$password']); print_r ($bind_vars); $res = $db->execute($cur, $bind_vars); } P.S. I also tagged this SimpleXML because that is how I am reading the file, though that code is not included above. It looks like this: $ref = simplexml_load_file($file); UPDATE: I've changed the code around as per suggestions, and now it is not always the same pattern, but it is equally broken. When I display the bind array before inserting, it looks like this. Note that I also count the rows before and after, so there are 0 rows, then I insert 1, then there are 2: 0 CSDs on that ITEM now. Array ( [0] => 2 [1] => 0 [2] => [3] => X [4] => XYZ [5] => [6] => [7] => [8] => audio [9] => [10] => 192.168.0.50 [11] => 192.168.0.3 [12] => 255.255.255.0 [13] => 255.255.255.0 [14] => [15] => [16] => [17] => 21 [18] => 5 [19] => Y [20] => /dir ) 2 CSDs on that ITEM now.

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  • How can I pipe two Perl CORE::system commands in a cross-platform way?

    - by Pedro Silva
    I'm writing a System::Wrapper module to abstract away from CORE::system and the qx operator. I have a serial method that attempts to connect command1's output to command2's input. I've made some progress using named pipes, but POSIX::mkfifo is not cross-platform. Here's part of what I have so far (the run method at the bottom basically calls system): package main; my $obj1 = System::Wrapper->new( interpreter => 'perl', arguments => [-pe => q{''}], input => ['input.txt'], description => 'Concatenate input.txt to STDOUT', ); my $obj2 = System::Wrapper->new( interpreter => 'perl', arguments => [-pe => q{'$_ = reverse $_}'}], description => 'Reverse lines of input input', output => { '>' => 'output' }, ); $obj1->serial( $obj2 ); package System::Wrapper; #... sub serial { my ($self, @commands) = @_; eval { require POSIX; POSIX->import(); require threads; }; my $tmp_dir = File::Spec->tmpdir(); my $last = $self; my @threads; push @commands, $self; for my $command (@commands) { croak sprintf "%s::serial: type of args to serial must be '%s', not '%s'", ref $self, ref $self, ref $command || $command unless ref $command eq ref $self; my $named_pipe = File::Spec->catfile( $tmp_dir, int \$command ); POSIX::mkfifo( $named_pipe, 0777 ) or croak sprintf "%s::serial: couldn't create named pipe %s: %s", ref $self, $named_pipe, $!; $last->output( { '>' => $named_pipe } ); $command->input( $named_pipe ); push @threads, threads->new( sub{ $last->run } ); $last = $command; } $_->join for @threads; } #... My specific questions: Is there an alternative to POSIX::mkfifo that is cross-platform? Win32 named pipes don't work, as you can't open those as regular files, neither do sockets, for the same reasons. 2. The above doesn't quite work; the two threads get spawned correctly, but nothing flows across the pipe. I suppose that might have something to do with pipe deadlocking or output buffering. What throws me off is that when I run those two commands in the actual shell, everything works as expected. Point 2 is solved; a -p fifo file test was not testing the correct file.

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  • XForms and multiple inputs for same model tag

    - by iHeartGreek
    Hi! I apologize ahead of time if I am not asking this properly.. it is hard to put into words what I am asking.. I have XForms model such as: <file> <criteria> <criterion></criterion> </criteria> </file> I want to have multiple input text boxes that create a new criterion tag. user interface such as: <xf:input ref="/file/criteria/criterion" model="select_data"> <xf:label>Select</xf:label> </xf:input> <xf:input ref="/file/criteria/criterion" model="select_data"> <xf:label>Select</xf:label> </xf:input> <xf:input ref="/file/criteria/criterion" model="select_data"> <xf:label>Select</xf:label> </xf:input> And I would like the XML output to look like this (once user has entered in info): <file> <criteria> <criterion>AAA</criterion> <criterion>BBB</criterion> <criterion>CCC</criterion> </criteria> </file> The way I have it doesn't work, as it sees the 3 input fields to be referring all to the same criterion tag. How do I differentiate? Thanks! I hope that made some sense! BEGIN FIRST EDIT Thanks for the responses for the basic text box! However, I now need to do this with a listbox. But for the life of me, I can't figure out how. I read somewhere to use with the xforms:select and deselect events.. but I didn't know where to place them, and the places I tried gave me very weird behaviour. I am currently implementing the following: <xf:select ref="instance('criteria_data')/criteria/criterion" selection="" appearance="compact" > <xf:label>Choose criteria</xf:label> <xf:itemset nodeset="instance('criteria_choices')/choice"> <xf:label ref="@label"></xf:label> <xf:value ref="."></xf:value> </xf:itemset> </xf:select> However when multiple choices are submitted, all selection values are inserted into the same node, separated by spaces. For example: If AAA and BBB and FFF were selected from listbox, it would result in the following XML: <criterion>AAA BBB FFF</criterion> How do I change my code to have each selection be in a separate node? i.e. I want it to look like this: <criterion>AAA</criterion> <criterion>BBB</criterion> <criterion>FFF</criterion> Thanks! END FIRST EDIT BEGIN SECOND EDIT: For the listboxes (ie xf:select appearance="compact") I ended up allowing the spaces to occur in the same node and then just transformed that xml using xsl to generate a properly formatted new xml doc (with separate individual nodes). Unfortunately, I did not find a less cumbersome solution by inserting them originally into separate nodes. The selected answer works very well for text boxes however, hence why I selected it as the answer. END SECOND EDIT

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  • WinRT WebView and Cookies

    - by javarg
    Turns out that WebView Control in WinRT is much more limited than it’s counterpart in WPF/Silverlight. There are some great articles out there in how to extend the control in order for it to support navigation events and some other features. For a personal project I'm working on, I needed to grab cookies a Web Site generated for the user. Basically, after a user authenticated to a Web Site I needed to get the authentication cookies and generate some extra requests on her behalf. In order to do so, I’ve found this great article about a similar case using SharePoint and Azure ACS. The secret is to use a p/invoke to native InternetGetCookieEx to get cookies for the current URL displayed in the WebView control.   void WebView_LoadCompleted(object sender, NavigationEventArgs e) { var urlPattern = "http://someserver.com/somefolder"; if (e.Uri.ToString().StartsWith(urlPattern)) { var cookies = InternetGetCookieEx(e.Uri.ToString()); // Do something with the cookies } } static string InternetGetCookieEx(string url) { uint sizeInBytes = 0; // Gets capacity length first InternetGetCookieEx(url, null, null, ref sizeInBytes, INTERNET_COOKIE_HTTPONLY, IntPtr.Zero); uint bufferCapacityInChars = (uint)Encoding.Unicode.GetMaxCharCount((int)sizeInBytes); // Now get cookie data var cookieData = new StringBuilder((int)bufferCapacityInChars); InternetGetCookieEx(url, null, cookieData, ref bufferCapacityInChars, INTERNET_COOKIE_HTTPONLY, IntPtr.Zero); return cookieData.ToString(); }   Function import using p/invoke follows: const int INTERNET_COOKIE_HTTPONLY = 0x00002000; [DllImport("wininet.dll", CharSet = CharSet.Unicode, SetLastError = true)] static extern bool InternetGetCookieEx(string pchURL, string pchCookieName, StringBuilder pchCookieData, ref System.UInt32 pcchCookieData, int dwFlags, IntPtr lpReserved); Enjoy!

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  • Converting world space coordinate to screen space coordinate and getting incorrect range of values

    - by user1423893
    I'm attempting to convert from world space coordinates to screen space coordinates. I have the following code to transform my object position Vector3 screenSpacePoint = Vector3.Transform(object.WorldPosition, camera.ViewProjectionMatrix); The value does not appear to be in screen space coordinates and is not limited to a [-1, 1] range. What step have I missed out in the conversion process? EDIT: Projection Matrix Perspective(game.GraphicsDevice.Viewport.AspectRatio, nearClipPlaneZ, farClipPlaneZ); private void Perspective(float aspect_Ratio, float z_NearClipPlane, float z_FarClipPlane) { nearClipPlaneZ = z_NearClipPlane; farClipPlaneZ = z_FarClipPlane; float yZoom = 1f / (float)Math.Tan(fov * 0.5f); float xZoom = yZoom / aspect_Ratio; matrix_Projection.M11 = xZoom; matrix_Projection.M12 = 0f; matrix_Projection.M13 = 0f; matrix_Projection.M14 = 0f; matrix_Projection.M21 = 0f; matrix_Projection.M22 = yZoom; matrix_Projection.M23 = 0f; matrix_Projection.M24 = 0f; matrix_Projection.M31 = 0f; matrix_Projection.M32 = 0f; matrix_Projection.M33 = z_FarClipPlane / (nearClipPlaneZ - farClipPlaneZ); matrix_Projection.M34 = -1f; matrix_Projection.M41 = 0f; matrix_Projection.M42 = 0f; matrix_Projection.M43 = (nearClipPlaneZ * farClipPlaneZ) / (nearClipPlaneZ - farClipPlaneZ); matrix_Projection.M44 = 0f; } View Matrix // Make our view matrix Matrix.CreateFromQuaternion(ref orientation, out matrix_View); matrix_View.M41 = -Vector3.Dot(Right, position); matrix_View.M42 = -Vector3.Dot(Up, position); matrix_View.M43 = Vector3.Dot(Forward, position); matrix_View.M44 = 1f; // Create the combined view-projection matrix Matrix.Multiply(ref matrix_View, ref matrix_Projection, out matrix_ViewProj); // Update the bounding frustum boundingFrustum.SetMatrix(matrix_ViewProj);

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