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  • binary files writing/reading problems...

    - by ScReYm0
    Ok i have problem with my code for reading binary file... First i will show you my writing code: void book_saving(char *file_name, struct BOOK *current) { FILE *out; BOOK buf; out = fopen(file_name, "wb"); if(out != NULL) { printf_s("Writting to file..."); do { if(current != NULL) { strcpy(buf.catalog_number, current-catalog_number); strcpy(buf.author, current-author); buf.price = current-price; strcpy(buf.publisher, current-publisher); strcpy(buf.title, current-title); buf.price = current-year_published; fwrite(&buf, sizeof(BOOK), 1, out); } current = current-next; }while(current != NULL); printf_s("Done!\n"); fclose(out); } } and here is my "version" for reading: int book_open(struct BOOK *current, char *file_name) { FILE *in; BOOK buf; BOOK *vnext; int count; int i; in = fopen("west", "rb"); printf_s("Reading database from %s...", file_name); if(!in) { printf_s("\nERROR!"); return 1; } i = fread(&buf,sizeof(BOOK), 1, in); while(!feof(in)) { if(current != NULL) { current = malloc(sizeof(BOOK)); current-next = NULL; } strcpy(current-catalog_number, buf.catalog_number); strcpy(current-title, buf.title); strcpy(current-publisher, buf.publisher); current-price = buf.price; current-year_published = buf.year_published; fread(&buf, 1, sizeof(BOOK), in); while(current-next != NULL) current = current-next; fclose(in); } printf_s("Done!"); return 0; } I just need to save my linked list in binary file and to be able to read it back ... please help me. The program just don't read it or its crash every time different situation ...

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  • XCode sqlite3 - SELECT always return SQLITE_DONE

    - by user573633
    Hi developers.... a noob here asking for help after a day of head-banging.... I am working on an app with sqlite3 database with one database and two tables. I have now come to a step where I want to select from the table with an argument. The code is here: -(NSMutableArray*) getGroupsPeopleWhoseGroupName:(NSString*)gn;{ NSMutableArray *groupedPeopleArray = [[NSMutableArray alloc] init]; const char *sql = "SELECT * FROM Contacts WHERE groupName='?'"; @try { NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES); NSString *docsDir = [paths objectAtIndex:0]; NSString *theDBPath = [docsDir stringByAppendingPathComponent:@"ContactBook.sqlite"]; if (!(sqlite3_open([theDBPath UTF8String], &database) == SQLITE_OK)) { NSLog(@"An error opening database."); } sqlite3_stmt *st; NSLog(@"debug004 - sqlite3_stmt success."); if (sqlite3_prepare_v2(database, sql, -1, &st, NULL) != SQLITE_OK) { NSLog(@"Error, failed to prepare statement."); } //DB is ready for accessing, now start getting all the info. while (sqlite3_step(st) == SQLITE_ROW) { MyContacts * aContact = [[MyContacts alloc] init]; //get contactID from DB. aContact.contactID = sqlite3_column_int(st, 0); if (sqlite3_column_text(st, 1) != NULL) { aContact.firstName = [NSString stringWithUTF8String:(char *) sqlite3_column_text(st, 1)]; } else { aContact.firstName = @""; } // here retrieve other columns data .... //store these info retrieved into the newly created array. [groupedPeopleArray addObject:aContact]; [aContact release]; } if(sqlite3_finalize(st) != SQLITE_OK) { NSLog(@"Failed to finalize data statement."); } if (sqlite3_close(database) != SQLITE_OK) { NSLog(@"Failed to close database."); } } @catch (NSException *e) { NSLog(@"An exception occurred: %@", [e reason]); return nil; } return groupedPeopleArray;} MyContacts is the class where I put up all the record variables. My problem is sqlite3_step(st) always return SQLITE_DONE, so that it i can never get myContacts. (i verified this by checking the return value). What am I doing wrong here? Many thanks in advance!

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  • IF Statement has strange behavior

    - by BSchlinker
    I've developed a 'custom' cout, so that I can display text to console and also print it to a log file. This cout class is passed a different integer on initialization, with the integer representing the verbosity level of the message. If the current verbosity level is greater then or equal to the verbosity level of the message, the message should print. The problem is, I have messages printing even when the current verbosity level is too low. I went ahead and debugged it, expecting to find the problem. Instead, I found multiple scenarios where my if statements are not working as expected. The statement if(ilralevel_passed <= ilralevel_set) will sometimes proceed even if ilralevel_set is LESS then ilralevel_passed. You can see this behavior in the following picture (my apologizes for using Twitpic) http://twitpic.com/1xtx4g/full. Notice how ilralevel_set is equal to zero, and ilralevel_passed is equal to one. Yet, the if statement has returned true and is now moving forward to pass the line to cout. I've never seen this type of behavior before and I'm not exactly sure how to proceed debugging it. I'm not able to isolate the behavior either -- it only occurs in certain parts of my program. Any suggestions are appreciated as always. // Here is an example use of the function: // ilra_status << setfill('0') << setw(2) << dispatchtime.tm_sec << endl; // ilra_warning << "Dispatch time (seconds): " << mktime(&dispatchtime) << endl; // Here is the 'custom' cout function: #ifndef ILRA_H_ #define ILRA_H_ // System libraries #include <iostream> #include <ostream> #include <sstream> #include <iomanip> // Definitions #define ilra_talk ilra(__FUNCTION__,0) #define ilra_update ilra(__FUNCTION__,0) #define ilra_error ilra(__FUNCTION__,1) #define ilra_warning ilra(__FUNCTION__,2) #define ilra_status ilra(__FUNCTION__,3) // Statics static int ilralevel_set = 0; static int ilralevel_passed; // Classes class ilra { public: // constructor / destructor ilra(const std::string &funcName, int toset) { ilralevel_passed = toset; } ~ilra(){}; // enable / disable irla functions static void ilra_verbose_level(int toset){ ilralevel_set = toset; } // output template <class T> ilra &operator<<(const T &v) { if(ilralevel_passed <= ilralevel_set) std::cout << v; return *this; } ilra &operator<<(std::ostream&(*f)(std::ostream&)) { if(ilralevel_passed <= ilralevel_set) std::cout << *f; return *this; } }; // end of the class #endif /* ILRA_H_ */

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  • Creating lots of arrays

    - by Dmitry
    Hello, everybody! May be that is a stupid question. How to create, say, 30 arrays (it doesn't matter of what type, say, char[])? It seems to me that it is not a good idea, to create them one by one by hand. I want to do that using a "for" cycle, but how should I specify identifiers?

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  • Recommendations for a C++ polymorphic, seekable, binary I/O interface

    - by Trevor Robinson
    I've been using std::istream and ostream as a polymorphic interface for random-access binary I/O in C++, but it seems suboptimal in numerous ways: 64-bit seeks are non-portable and error-prone due to streampos/streamoff limitations; currently using boost/iostreams/positioning.hpp as a workaround, but it requires vigilance Missing operations such as truncating or extending a file (ala POSIX ftruncate) Inconsistency between concrete implementations; e.g. stringstream has independent get/put positions whereas filestream does not Inconsistency between platform implementations; e.g. behavior of seeking pass the end of a file or usage of failbit/badbit on errors Don't need all the formatting facilities of stream or possibly even the buffering of streambuf streambuf error reporting (i.e. exceptions vs. returning an error indicator) is supposedly implementation-dependent in practice I like the simplified interface provided by the Boost.Iostreams Device concept, but it's provided as function templates rather than a polymorphic class. (There is a device class, but it's not polymorphic and is just an implementation helper class not necessarily used by the supplied device implementations.) I'm primarily using large disk files, but I really want polymorphism so I can easily substitute alternate implementations (e.g. use stringstream instead of fstream for unit tests) without all the complexity and compile-time coupling of deep template instantiation. Does anyone have any recommendations of a standard approach to this? It seems like a common situation, so I don't want to invent my own interfaces unnecessarily. As an example, something like java.nio.FileChannel seems ideal. My best solution so far is to put a thin polymorphic layer on top of Boost.Iostreams devices. For example: class my_istream { public: virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) = 0; virtual std::streamsize read(char* s, std::streamsize n) = 0; virtual void close() = 0; }; template <class T> class boost_istream : public my_istream { public: boost_istream(const T& device) : m_device(device) { } virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) { return boost::iostreams::seek(m_device, off, way); } virtual std::streamsize read(char* s, std::streamsize n) { return boost::iostreams::read(m_device, s, n); } virtual void close() { boost::iostreams::close(m_device); } private: T m_device; };

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  • filebuf in ifstream and ofstream

    - by Juan
    How can i set a new char array to be the buffer of a fstream's filebuf, there is a function (setbuf) in the filebuf but it is protected. while searching on the web, some sites mention fstream::setbuf but it doesn't seem to exist anymore. Thanks

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  • Glob function (c) and backup file (file~)

    - by arnoras
    I'm using glob function for a autocompletion function. I'm showing you the problem because it's difficult to explain: matched = ~/.tcsh glob(matched, 0, NULL, &pglob); glob put all matched files in a char ** and when I print it I have: case[0] = .tcshrc case[1] = I should have .tcshrc~ in case[1], but nothing =S, I've seen a flag "GLOB_TILDE" like this " glob(matched, GLOB_TILDE, NULL, &pglob); But it doesn't change anything! Can someone help me?

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  • Dojo script (fx.xd.js) not working IE

    - by Andy Walpole
    Hi folks, I've been teaching myself Dojo over the last few days... However, if you look at the following page: http://www.mechanic-one.suburban-glory.com/ You'll see that the simple script in the header doesn't work in IE I get the following message: Message: 'duration' is null or not an object Line: 8 Char: 622 Code: 0 URI: htt p://ajax.googleapis.com/ajax/libs/dojo/1.3.2/dojo/fx.xd.js Do you have any ideas why this is so? Andy

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  • Denormalization of large text?

    - by tesmar
    If I have large articles that need to be stored in a database, each associated with many tables would a NoSQL option help? Should I copy the 1000 char articles over multiple "buckets", duplicating them each time they are related to a bucket or should I use a normalized MySQL DB with lots of Memcache?

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  • How to maxmise the largest contiguous block of memory in the Large Object Heap

    - by Unsliced
    The situation is that I am making a WCF call to a remote server which is returns an XML document as a string. Most of the time this return value is a few K, sometimes a few dozen K, very occasionally a few hundred K, but very rarely it could be several megabytes (first problem is that there is no way for me to know). It's these rare occasions that are causing grief. I get a stack trace that starts: System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown. at System.Xml.BufferBuilder.AddBuffer() at System.Xml.BufferBuilder.AppendHelper(Char* pSource, Int32 count) at System.Xml.BufferBuilder.Append(Char[] value, Int32 start, Int32 count) at System.Xml.XmlTextReaderImpl.ParseText() at System.Xml.XmlTextReaderImpl.ParseElementContent() at System.Xml.XmlTextReaderImpl.Read() at System.Xml.XmlTextReader.Read() at System.Xml.XmlReader.ReadElementString() at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderMDRQuery.Read2_getMarketDataResponse() at Microsoft.Xml.Serialization.GeneratedAssembly.ArrayOfObjectSerializer2.Deserialize(XmlSerializationReader reader) at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events) at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle) at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) I've read around and it is because the Large Object Heap is just getting too fragmented, so even preceding the call with a quick check to StringBuilder.EnsureCapacity just causes the OutOfMemoryException to be thrown earlier (and because I'm guessing at what's needed, it might not actually need that much so my check is causing more problems than it is solving). Some opinions are that there's not much I can do about it. Some of the questions I've asked myself: Use less memory - have you checked for leaks? Yes. The memory usage goes up and down, but there's no fundamental growth that guarantees this to happen. Some of the times it fails, it succeeded at that stage previously. Transfer smaller amounts Not an option, this is a third party web service over which I have no control (or at least it would take a long time to resolve, in the meantime I still have a problem) Can you do something to the LOH to make it less likely to fail? ... now this is most fruitful course. It's a 32-bit process (it has to be for various political, technical and boring reasons) but there's normally hundreds of meg free (multiples of the largest amount for which we've seen failures). Can we monitor the LOH? Using perfmon I can track the size of the heaps, but I don't think there's a way to monitor the largest available contiguous block of memory. Question is: any advice or suggestions for things to try?

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  • What is the best way to store incremental downloaded data?

    - by afriza
    Inspired by Chromium's sha1 class, I am thinking to store incrementally downloaded data using std::string // pseudo-code char buff[BUFF_SIZE]; std::string data; do { size = ReadInternetFileTo(buff,BUFF_SIZE); data.append(buff,size); } while (not_finished); Any foreseeable problems with this method or better way to do it?

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  • Check for a string format...

    - by ThePower
    I need an simple way to check whether a string that is sent to my function is of the form: (x + n)(x + m) //the +'s can be minus' //n and m represent a double //x represents the char 'x' Is there a simple string format that I can use to check that this is the form. As opposed to checking each character singularly. The whitespace will be removed to save any confusion. Regards Lloyd

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  • How to encrypt and save a binary stream after serialization and read it back?

    - by Anindya Chatterjee
    I am having some problems in using CryptoStream when I want to encrypt a binary stream after binary serialization and save it to a file. I am getting the following exception System.ArgumentException : Stream was not readable. Can anybody please show me how to encrypt a binary stream and save it to a file and deserialize it back correctly? The code is as follows: class Program { public static void Main(string[] args) { var b = new B {Name = "BB"}; WriteFile<B>(@"C:\test.bin", b, true); var bb = ReadFile<B>(@"C:\test.bin", true); Console.WriteLine(b.Name == bb.Name); Console.ReadLine(); } public static T ReadFile<T>(string file, bool decrypt) { T bObj = default(T); var _binaryFormatter = new BinaryFormatter(); Stream buffer = null; using (var stream = new FileStream(file, FileMode.OpenOrCreate)) { if(decrypt) { const string strEncrypt = "*#4$%^.++q~!cfr0(_!#$@$!&#&#*&@(7cy9rn8r265&$@&*E^184t44tq2cr9o3r6329"; byte[] dv = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; CryptoStream cs; DESCryptoServiceProvider des = null; var byKey = Encoding.UTF8.GetBytes(strEncrypt.Substring(0, 8)); using (des = new DESCryptoServiceProvider()) { cs = new CryptoStream(stream, des.CreateEncryptor(byKey, dv), CryptoStreamMode.Read); } buffer = cs; } else buffer = stream; try { bObj = (T) _binaryFormatter.Deserialize(buffer); } catch(SerializationException ex) { Console.WriteLine(ex.Message); } } return bObj; } public static void WriteFile<T>(string file, T bObj, bool encrypt) { var _binaryFormatter = new BinaryFormatter(); Stream buffer; using (var stream = new FileStream(file, FileMode.Create)) { try { if(encrypt) { const string strEncrypt = "*#4$%^.++q~!cfr0(_!#$@$!&#&#*&@(7cy9rn8r265&$@&*E^184t44tq2cr9o3r6329"; byte[] dv = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; CryptoStream cs; DESCryptoServiceProvider des = null; var byKey = Encoding.UTF8.GetBytes(strEncrypt.Substring(0, 8)); using (des = new DESCryptoServiceProvider()) { cs = new CryptoStream(stream, des.CreateEncryptor(byKey, dv), CryptoStreamMode.Write); buffer = cs; } } else buffer = stream; _binaryFormatter.Serialize(buffer, bObj); buffer.Flush(); } catch(SerializationException ex) { Console.WriteLine(ex.Message); } } } } [Serializable] public class B { public string Name {get; set;} } It throws the serialization exception as follows The input stream is not a valid binary format. The starting contents (in bytes) are: 3F-17-2E-20-80-56-A3-2A-46-63-22-C4-49-56-22-B4-DA ...

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  • UNIQUE CONSTRAINT on a column from foreign table in SQL Server 2008

    - by bodziec
    I have two tables: create table [dbo].[Main] ( [ID] [int] identity(1,1) primary key not null, [Sign] [char](1) not null ) create table [dbo].[Names] ( [ID_Main][int] primary key not null, [Name][nvarchar](128) not null, constraint [FK_Main_Users] foreign key ([ID_Main]) references [dbo].[Main]([ID]), constraint [CK_Name] unique ([Name], [Sign]) ) The problem is with the second constraint CK_Name Is there a way to make a constraint target column from a foreign table?

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  • generic programming in C with void pointer.

    - by Nyan
    Hi everyone, even though it is possible to write generic code in C using void pointer(generic pointer), I find that it is quite difficult to debug the code since void pointer can take any pointer type without warning from compiler. (e.g function foo() take void pointer which is supposed to be pointer to struct, but compiler won't complain if char array is passed.) What kind of approach/strategy do you all use when using void pointer in C?

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  • Strange behavior of move with strings

    - by Umair Ahmed
    I am testing some enhanced string related functions with which I am trying to use move as a way to copy strings around for faster, more efficient use without delving into pointers. While testing a function for making a delimited string from a TStringList, I encountered a strange issue. The compiler referenced the bytes contained through the index when it was empty and when a string was added to it through move, index referenced the characters contained. Here is a small downsized barebone code sample:- unit UI; interface uses System.SysUtils, System.Types, System.UITypes, System.Rtti, System.Classes, System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.Layouts, FMX.Memo; type TForm1 = class(TForm) Results: TMemo; procedure FormCreate(Sender: TObject); end; var Form1: TForm1; implementation {$R *.fmx} function StringListToDelimitedString ( const AStringList: TStringList; const ADelimiter: String ): String; var Str : String; Temp1 : NativeInt; Temp2 : NativeInt; DelimiterSize : Byte; begin Result := ' '; Temp1 := 0; DelimiterSize := Length ( ADelimiter ) * 2; for Str in AStringList do Temp1 := Temp1 + Length ( Str ); SetLength ( Result, Temp1 ); Temp1 := 1; for Str in AStringList do begin Temp2 := Length ( Str ) * 2; // Here Index references bytes in Result Move ( Str [1], Result [Temp1], Temp2 ); // From here the index seems to address characters instead of bytes in Result Temp1 := Temp1 + Temp2; Move ( ADelimiter [1], Result [Temp1], DelimiterSize ); Temp1 := Temp1 + DelimiterSize; end; end; procedure TForm1.FormCreate(Sender: TObject); var StrList : TStringList; Str : String; begin // Test 1 : StringListToDelimitedString StrList := TStringList.Create; Str := ''; StrList.Add ( 'Hello1' ); StrList.Add ( 'Hello2' ); StrList.Add ( 'Hello3' ); StrList.Add ( 'Hello4' ); Str := StringListToDelimitedString ( StrList, ';' ); Results.Lines.Add ( Str ); StrList.Free; end; end. Please devise a solution and if possible, some explanation. Alternatives are welcome too.

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  • Error in ternary expression

    - by Bipul
    Consider the following code which shows compile time error : #include <stdio.h> int main(int argc, char** argv) { int x=5,y=0,z=2; int a=z?x,y?x:(y); // but z?x,y?x:y:z is not showing any error printf("%d",a); return 0; } Please help me explain the reason why z?x,y?x:y:z is not showing any error?

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  • question regarding the warning that comes everywhere

    - by user177893
    Hi, Would you be able to help to delete the warning discussed below ? I have one file example.h In that I declared static const NSString *variable = @"cool"; Now, I have another file multiple.m. In this file I have a function Bool var2 = [object methodname:variable]; It means, I passed variable as parameter for this function, but I got warning like this: variable is defined but not used So,how to remove this warning? please help me

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  • Why doesn't SQL DISTINCT work with ORDER BY CAST?

    - by Tommy
    Including DISTINCT to an SQL query that also uses ORDER BY CAST(thecolumn AS int) as shown here seems to remove that sorting functionality. Any reason these cant work together? (Using sqlite with the C api) Thanks. EDIT: Started with - sprintf(sql, "SELECT DISTINCT rowX FROM TableX Order By Cast(rowX As int) LIMIT 150 OFFSET %s;", Offset); rowX is Type CHAR(5)

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  • UNIQUE CONSTRAINT on a column from foreign table in MSSQL2008

    - by bodziec
    Hi, I have two tables: create table [dbo].[Main] ( [ID] [int] identity(1,1) primary key not null, [Sign] [char](1) not null ) create table [dbo].[Names] ( [ID_Main][int] primary key not null, [Name][nvarchar](128) not null, constraint [FK_Main_Users] foreign key ([ID_Main]) references [dbo].[Main]([ID]), constraint [CK_Name] unique ([Name], [Sign]) ) The problem is with the second constraint CK_Name Is there a way to make a constraint target column from a foreign table?

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  • How to solve Memory leaks in Lib Xml Parser in objective-C where the list is returned?

    - by Madan Mohan
    Hi Guys, I got leaks in Lib Xml Parser while retrieving the data from the net, Here in the below code, I have allocated the list - (void)getCustomersList { // make an operation so we can push it into the queue SEL method = @selector(parseForData); NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:method object:nil]; customersTempList = [[NSMutableArray alloc] initWithCapacity:20];// allocated list [self.retrieverQueue addOperation:op]; [op release]; } // return each recode // in parser .m class one of the condition in endElement where it shows a leak. else if(0 == strncmp((const char *)localname, kCustomerElement, kCustomerElementLength)) { [customersTempList addObject:customer]; printf("\n no of objects in temp list:%d", [customersTempList count]); if ([customersTempList count] == 20) { NSMutableArray* argsList = [customersTempList copy];//////////////////////here it is showing leak. printf("\n Calling reload data with %d new objects", [argsList count]); SEL selector = @selector(parser:addCustomerObject:); NSMethodSignature *sig = [(id)self.delegate methodSignatureForSelector:selector]; if(nil != sig && [self.delegate respondsToSelector:selector]) { NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:sig]; [invocation retainArguments]; [invocation setTarget:self.delegate]; [invocation setSelector:selector]; [invocation setArgument:&self atIndex:2]; [invocation setArgument:&argsList atIndex:3]; [invocation performSelectorOnMainThread:@selector(invoke) withObject:NULL waitUntilDone:NO]; } [customersTempList removeAllObjects]; } } // returned the list after all the records are stored in the list else if(0 == strncmp((const char *)localname, kCustomersElement, kCustomersElementLength)) { printf("\n Calling reload data with %d new objects", [customersTempList count]); NSMutableArray* argsList = [customersTempList copy]; printf("\n Calling reload data with %d new objects", [argsList count]); SEL selector = @selector(parser:addCustomerObject:); NSMethodSignature *sig = [(id)self.delegate methodSignatureForSelector:selector]; if(nil != sig && [self.delegate respondsToSelector:selector]) { NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:sig]; [invocation retainArguments]; [invocation setTarget:self.delegate]; [invocation setSelector:selector]; [invocation setArgument:&self atIndex:2]; [invocation setArgument:&argsList atIndex:3]; [invocation performSelectorOnMainThread:@selector(invoke) withObject:NULL waitUntilDone:NO]; } [customersTempList removeAllObjects]; } } please help me out of this, Thanks, Madan.

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