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  • Why is address zero used for null pointer?

    - by Joel
    In C (or C++ for that matter), pointers are special if they have the value zero: I am adviced to set pointers to zero after freeing their memory, because it means freeing the pointer again isn't dangerous; when I call malloc it returns a pointer with the value zero if it can't get me memory; I use if (p != 0) all the time to make sure passed pointers are valid etc. But since memory addressing starts at 0, isn't 0 just as a valid address as any other? How can 0 be used for handling null pointers if that is the case? Why isn't a negative number null instead?

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  • Freeing a character pointer returns error

    - by Kraffs
    I'm trying to free a character pointer after having used it but it returns a strange error. The error says: "_CrtDbgREport: String too long or IO Error" The debugger itself returns no errors while compiling. The code currently looks like this: void RespondToUser(SOCKET client, SOCKET server) { char buffer[80]; char *temp = malloc(_scprintf("HTTP/1.1 200 OK\r\n%s\r\nServer: %s\r\nConnection: close\r\n\r\nHi!", buffer, SERVER_NAME)); sprintf(temp, "HTTP/1.1 200 OK\r\n%s\r\nServer: %s\r\nConnection: close\r\n\r\nHi!", buffer, SERVER_NAME); send(client, temp, strlen(temp), 0); closesocket(client); free(temp); ListenToUsers(server); } The problem only occurs when I try to free the temp pointer from the memory and not otherwise. What might be causing this?

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  • C pointer initialization and dereferencing, what's wrong here?

    - by randombits
    This should be super simple, but I'm not sure why the compiler is complaining here. #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { int *n = 5; printf ("n: %d", *n); exit(0); } Getting the following complaints: foo.c: In function ‘main’: foo.c:6: warning: initialization makes pointer from integer without a cast I just want to print the value that the pointer n references. I'm dereferencing it in the printf() statement and I get a segmentation fault. Compiling this with gcc -o foo foo.c.

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  • Null Pointer Exception with an array of bitsets

    - by p0ny
    could someone explain to me why the following results in a Null pointer Exception? And how to set a value for bitarray[0]? BitSet[] bitarray; bitarray= new BitSet[10]; bitarray[0].set(1); Also, why something like this work and not result in a pointer exception? BitSet[] bitarray = new BitSet[10]; BitSet bits = new BitSet(32); bits.set(1); bitarray[0] = bits; Thanks

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  • Set argument pointer to point to new memory inside a function (without returning it) IN C

    - by user321605
    Hello, Hopefully my title was descriptive enough to attract the right help. I want to write a function that will return 1 thing, and modify a provided pointer in another. My current function declaration is . . . char * afterURL replaceURLS(char * body) What I want to do is copy all of body's data into a new string, and set body to point to this new data. I then want afterURL to point to a location within the new string. My issue is getting the actual pointer that is passed in to this function to point to the new data. Thanks in advance! Rob

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  • Referencing an array to a pointer

    - by james
    I want to refer a pointer to an array by another pointer. Example: void exp() { double var[2]; exp1(&var[0]); printf("\n varvalue is %lf\n",var[0]); } void exp1(double *var) { //updating the value *var[0]=4.0; exp2(&var[0]); } void exp2(double *var) { *var[0]=7.0; } This should update the value as 7.0(the last update).I am getting an array like invalid argument type of unary(*) . How can i correct this?where i am going wrong here?

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  • A pointer member variable having different values

    - by Rohan Prabhu
    Ok, to begin with, this is my code: HyperSprite::HyperSprite() { _view = 0; } void HyperSprite::publish(QGraphicsView* view) { _view = view; } void HyperSprite::getKFrame() { if(_view != 0) { qDebug()<<(void*)_view; } } Now, if I call HyperSprite::getKFrame() from within main(), I get the output: 0xbf8ffb84 I have a TCP server, which requires this QGraphicsView* variable. So whenever a new connection is made, HyperSprite::getKFrame() is called. However, whenever I make a connection to my server, this is the output: 0x1e425ff I honestly don't understand this. Shouldn't the value of a member remain same throughout? Why is the pointer value changing? As is obvious, whenever I try to use the _view pointer to access any of its members, a Segmentation Fault occurs. I tried using QSharedPointer, but it also results in the same problem. The data of the QSharedPointer automatically changes. Why is this happening?

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  • Reading function pointer syntax

    - by bobobobo
    Everytime I look at a C function pointer, my eyes glaze over. I can't read them. From here, here are 2 examples of function pointer TYPEDEFS: typedef int (*AddFunc)(int,int); typedef void (*FunctionFunc)(); Now I'm used to something like: typedef vector<int> VectorOfInts ; Which I read as typedef vector<int> /* as */ VectorOfInts ; But I can't read the above 2 typedefs. The bracketing and the asterisk placement, it's just not logical. Why is the * beside the word AddFunc..?

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  • how to copy an array into somewhere else in the memory by using the pointer

    - by user2758510
    I am completely new in c++ programming. I want to copy the array called distances into where pointer is pointing to and then I want to print out the resul to see if it is worked or not. this is what I have done: int distances[4][6]={{1,0,0,0,1,0},{1,1,0,0,1,1},{1,0,0,0,0,0},{1,1,0,1,0,0}}; int *ptr; ptr = new int[sizeof(distances[0])]; for(int i=0; i<sizeof(distances[0]); i++){ ptr=distances[i]; ptr++; } I do not know how to print out the contents of the pointer to see how it works.

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  • pointer and malloc [closed]

    - by gcc
    How many methods/ways are there taking input by using with pointer and dynamic memory? Input: 3 1 2 n k l 2 1 2 p 4 55 62 * # x (x is stop value, first input always integer) Example code: p=malloc(sizeof(int)); scanf("%d",&num_arrays); while(1) { scanf("%c",&(*(p+i))); if(*(p+i)=='x') break; ++i; } "3" is stored in num_arrays. The other input values are stored in pointer[array].

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  • How to convert a void pointer to array of classes

    - by user99545
    I am trying to convert a void pointer to an array of classes in a callback function that only supports a void pointer as a means of passing paramaters to the callback. class person { std::string name, age; }; void callback (void *val) { for (int i = 0; i < 9; i++) { std::cout << (person [])val[i].name; } } int main() { person p[10]; callback((void*)p); } My goal is to be able to pass an array of the class person to the callback which then prints out the data such as their name and age. However, the compile does not like what I am doing and complains that error: request for member 'name' in 'val', which is of non-class type 'void*' How can I go about doing this?

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  • base pointer to derived class

    - by Jay
    Suppose there are Base class and Derived class. Base *A = new Base; Here A is a pointer point to Base class, and new constructs one that A points to. I also saw Base *B = new Derived; How to explain this? B is a pointer to Base Class, and a Derived class constructed and pointed by B? If there is a function derived from Base class, say, Virtual void f(), and it's been overridden in Derived class, then B->f() will invoke which version of the function? version in Base class, or version that overridden in Derived Class. What if there is a new function void g()in Derived, is B->g() going to invoke this function properly? One more is, is int *a = new double; or int *a = new int; legal?

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  • SQLiteOpenHelper.getWriteableDatabase() null pointer exception on Android

    - by Drew Dara-Abrams
    I've had fine luck using SQLite with straight, direct SQL in Android, but this is the first time I'm wrapping a DB in a ContentProvider. I keep getting a null pointer exception when calling getWritableDatabase() or getReadableDatabase(). Is this just a stupid mistake I've made with initializations in my code or is there a bigger issue? public class DatabaseProvider extends ContentProvider { ... private DatabaseHelper databaseHelper; private SQLiteDatabase db; ... @Override public boolean onCreate() { databaseHelper = new DatabaseProvider.DatabaseHelper(getContext()); return (databaseHelper == null) ? false : true; } ... @Override public Uri insert(Uri uri, ContentValues values) { db = databaseHelper.getWritableDatabase(); // NULL POINTER EXCEPTION HERE ... } private static class DatabaseHelper extends SQLiteOpenHelper { public static final String DATABASE_NAME = "cogsurv.db"; public static final int DATABASE_VERSION = 1; public static final String[] TABLES = { "people", "travel_logs", "travel_fixes", "landmarks", "landmark_visits", "direction_distance_estimates" }; // people._id does not AUTOINCREMENT, because it's set based on server's people.id public static final String[] CREATE_TABLE_SQL = { "CREATE TABLE people (_id INTEGER PRIMARY KEY," + "server_id INTEGER," + "name VARCHAR(255)," + "email_address VARCHAR(255))", "CREATE TABLE travel_logs (_id INTEGER PRIMARY KEY AUTOINCREMENT," + "server_id INTEGER," + "person_local_id INTEGER," + "person_server_id INTEGER," + "start DATE," + "stop DATE," + "type VARCHAR(15)," + "uploaded VARCHAR(1))", "CREATE TABLE travel_fixes (_id INTEGER PRIMARY KEY AUTOINCREMENT," + "datetime DATE, " + "latitude DOUBLE, " + "longitude DOUBLE, " + "altitude DOUBLE," + "speed DOUBLE," + "accuracy DOUBLE," + "travel_mode VARCHAR(50), " + "person_local_id INTEGER," + "person_server_id INTEGER," + "travel_log_local_id INTEGER," + "travel_log_server_id INTEGER," + "uploaded VARCHAR(1))", "CREATE TABLE landmarks (_id INTEGER PRIMARY KEY AUTOINCREMENT," + "server_id INTEGER," + "name VARCHAR(150)," + "latitude DOUBLE," + "longitude DOUBLE," + "person_local_id INTEGER," + "person_server_id INTEGER," + "uploaded VARCHAR(1))", "CREATE TABLE landmark_visits (_id INTEGER PRIMARY KEY AUTOINCREMENT," + "server_id INTEGER," + "person_local_id INTEGER," + "person_server_id INTEGER," + "landmark_local_id INTEGER," + "landmark_server_id INTEGER," + "travel_log_local_id INTEGER," + "travel_log_server_id INTEGER," + "datetime DATE," + "number_of_questions_asked INTEGER," + "uploaded VARCHAR(1))", "CREATE TABLE direction_distance_estimates (_id INTEGER PRIMARY KEY AUTOINCREMENT," + "server_id INTEGER," + "person_local_id INTEGER," + "person_server_id INTEGER," + "travel_log_local_id INTEGER," + "travel_log_server_id INTEGER," + "landmark_visit_local_id INTEGER," + "landmark_visit_server_id INTEGER," + "start_landmark_local_id INTEGER," + "start_landmark_server_id INTEGER," + "target_landmark_local_id INTEGER," + "target_landmark_server_id INTEGER," + "datetime DATE," + "direction_estimate DOUBLE," + "distance_estimate DOUBLE," + "uploaded VARCHAR(1))" }; public DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); Log.v(Constants.TAG, "DatabaseHelper()"); } @Override public void onCreate(SQLiteDatabase db) { Log.v(Constants.TAG, "DatabaseHelper.onCreate() starting"); // create the tables int length = CREATE_TABLE_SQL.length; for (int i = 0; i < length; i++) { db.execSQL(CREATE_TABLE_SQL[i]); } Log.v(Constants.TAG, "DatabaseHelper.onCreate() finished"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { for (String tableName : TABLES) { db.execSQL("DROP TABLE IF EXISTS" + tableName); } onCreate(db); } } } As always, thanks for the assistance! -- Not sure if this detail helps, but here's LogCat showing the exception:

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  • Adding rows to a data-bound DataGridView [Winforms]

    - by Mishko
    I want to bind a table from a database to a DataGridView, but I want to also add one more row with a sum of the values in the columns with indexes 3,4,7,8,9... How can I do that? Thanks! DataTable table1 = new DataTable(); double brutoUkupno1 = 0; double porezUkupno1 = 0; double doprinosUkupno1 = 0; double netoUkupno1 = 0; double doprinosTeretUkupno1 = 0; double topliObrokUkupno1 = 0; double regresUkupno1 = 0; Connection con = new Connection(); table1 = con.boundTable(month, Convert.ToInt32(year)); //This is method which returns DataTable table1.Rows.Add(null, null, null, null, null, null, null, null, null, null, null, null, null, null); table1.Rows.Add(null, null, null, null, null, null, null, null, null, null, null, null, null, null); dgv2.Visible = true; dgv2.DataSource = table1; for (int i = 0; i < dgv2.RowCount - 2; i++) { topliObrokUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[7].Value); regresUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[8].Value); brutoUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[9].Value); porezUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[10].Value); doprinosUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[11].Value); netoUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[12].Value); doprinosTeretUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[13].Value); //Now I am having problems with this below, putting things above to dgv2 : } dgv2.Rows[dgv2.Rows.Count - 1].Cells[0].Value = "Ukupno"; dgv2.Rows[dgv2.Rows.Count - 1].Cells[3].Value = month.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[4].Value = year.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[7].Value = topliObrokUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[8].Value = regresUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[9].Value = brutoUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[10].Value = porezUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[11].Value = doprinosUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[12].Value = netoUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[13].Value = doprinosTeretUkupno1.ToString(); dgv2.Rows[dgv2.RowCount - 2].Height = 3; dgv2.Rows[dgv2.RowCount - 2].DefaultCellStyle.BackColor = Color.Black;

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  • global static boolean pointer causes segmentation fault using pthread

    - by asksw0rder
    New to pthread programming, and stuck on this error when working on a C++&C mixed code. What I have done is to call the c code in the thread created by the c++ code. There is a static boolean pointer used in the thread and should got free when the thread finishes. However I noticed that every time when the program processed into the c function, the value of the boolean pointer would be changed and the segmentation fault then happened due to the free(). Detail code is as follows: static bool *is_center; // omit other codes in between ... void streamCluster( PStream* stream) { // some code here ... while(1){ // some code here ... is_center = (bool*)calloc(points.num,sizeof(bool)); // start the parallel thread here. // the c code is invoked in this function. localSearch(&points,kmin, kmax,&kfinal); // parallel free(is_center); } And the function using parallel is as follows (my c code is invoked in each thread): void localSearch( Points* points, long kmin, long kmax, long* kfinal ) { pthread_barrier_t barrier; pthread_t* threads = new pthread_t[nproc]; pkmedian_arg_t* arg = new pkmedian_arg_t[nproc]; pthread_barrier_init(&barrier,NULL,nproc); for( int i = 0; i < nproc; i++ ) { arg[i].points = points; arg[i].kmin = kmin; arg[i].kmax = kmax; arg[i].pid = i; arg[i].kfinal = kfinal; arg[i].barrier = &barrier; pthread_create(threads+i,NULL,localSearchSub,(void*)&arg[i]); } for ( int i = 0; i < nproc; i++) { pthread_join(threads[i],NULL); } delete[] threads; delete[] arg; pthread_barrier_destroy(&barrier); } Finally the function calling my c code: void* localSearchSub(void* arg_) { // omit some initialize code... // my code begin_papi_thread(&eventSet); // Processing k-means, omit codes. // is_center value will be updated correctly // my code end_papi_thread(&eventSet); // when jumping into this, error happens return NULL; } And from gdb, what I have got for the is_center is: Breakpoint 2, localSearchSub (arg_=0x600000000000bc40) at streamcluster.cpp:1711 1711 end_papi_thread(&eventSet); (gdb) s Hardware watchpoint 1: is_center Old value = (bool *) 0x600000000000bba0 New value = (bool *) 0xa93f3 0x400000000000d8d1 in localSearchSub (arg_=0x600000000000bc40) at streamcluster.cpp:1711 1711 end_papi_thread(&eventSet); Any suggestions? Thanks in advance!

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  • I have problems with adding rows to data-binded DataGridView in desktop app.

    - by Mishko
    DataTable table1 = new DataTable(); double brutoUkupno1 = 0; double porezUkupno1 = 0; double doprinosUkupno1 = 0; double netoUkupno1 = 0; double doprinosTeretUkupno1 = 0; double topliObrokUkupno1 = 0; double regresUkupno1 = 0; Connection con = new Connection(); table1 = con.boundTable(month, Convert.ToInt32(year)); //This is method which returns DataTable table1.Rows.Add(null, null, null, null, null, null, null, null, null, null, null, null, null, null); table1.Rows.Add(null, null, null, null, null, null, null, null, null, null, null, null, null, null); dgv2.Visible = true; dgv2.DataSource = table1; for (int i = 0; i < dgv2.RowCount - 2; i++) { topliObrokUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[7].Value); regresUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[8].Value); brutoUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[9].Value); porezUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[10].Value); doprinosUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[11].Value); netoUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[12].Value); doprinosTeretUkupno1 += Convert.ToDouble(dgv2.Rows[i].Cells[13].Value); //Now I am having problems with this below, putting things above to dgv2 : } dgv2.Rows[dgv2.Rows.Count - 1].Cells[0].Value = "Ukupno"; dgv2.Rows[dgv2.Rows.Count - 1].Cells[3].Value = month.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[4].Value = year.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[7].Value = topliObrokUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[8].Value = regresUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[9].Value = brutoUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[10].Value = porezUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[11].Value = doprinosUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[12].Value = netoUkupno1.ToString(); dgv2.Rows[dgv2.Rows.Count - 1].Cells[13].Value = doprinosTeretUkupno1.ToString(); dgv2.Rows[dgv2.RowCount - 2].Height = 3; dgv2.Rows[dgv2.RowCount - 2].DefaultCellStyle.BackColor = Color.Black;

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  • passing arg2 of 'listFind' from incompatible pointer type

    - by lego69
    Hello, I've got some problem with my function and don't know how to solve this problem, This is my code: ListResult result=listFind(currentLines, compareBasicLines, &linePrototype); <-here problem compareBasicLines pointer to function int compareBasicLines(ptrLine line1, ptrLine line2){ COMPARE_NUMBER_STRINGS(line1, line2); } COMPARE_NUMBER_STRINGS(line1, line2); defined in another file #define COMPARE_NUMBER_STRINGS(var1, var2) \ if(var1 == NULL || var2 == NULL){ \ return 0; \ } \ return strcmp(var1->strNumber, var2->strNumber); thanks in advance for everyone

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  • reopen or read and say why not reopened [closed]

    - by gcc
    input 23 3 4 4 42 n 23 0 9 9 n n n 3 9 9 x //according to input,i should create int pointer arrays. pointer arrays // starting from 1 (that is initial arrays is arrays[1].when program sees n ,it // must be jumb to arrays 2 // the first int input 23 is num_arrays which used in malloc(sizeof(int)*num_arrays expected output: elements of arrays[1] 3 4 5 42 elements of arrays[2] 23 0 9 9 elements of arrays[5] 3 9 9 another input 12 2 3 4 n n 2 3 4 n 12 3 x expected output elements of arrays[1] 2 3 4 elements of arrays[3] 2 3 4 elements of arrays[4] 12 3 specification: x is stopper n is comman to create new pointer array i am new in this site anyone help me how can i write

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  • MVVM - ListBox SelectedItem Binding Property Going Null

    - by Peanut
    So i have a listbox: <ListBox x:Name="listbox" HorizontalAlignment="Left" Margin="8,8,0,8" Width="272" BorderBrush="{x:Null}" Background="{x:Null}" Foreground="{x:Null}" ItemsSource="{Binding MenuItems}" ItemTemplate="{DynamicResource MenuItemsTemplate}" SelectionChanged="ListBox_SelectionChanged" SelectedItem="{Binding SelectedItem}"> </ListBox> and i have this included in my viewmodel: public ObservableCollection<MenuItem> MenuItems { get { return menuitems; } set { menuitems = value; NotifyPropertyChanged("MenuItems"); } } public MenuItem SelectedItem { get { return selecteditem; } set { selecteditem = value; NotifyPropertyChanged("SelectedItem"); } } and also in my viewmodel: public void UpdateStyle() { ActiveHighlight = SelectedItem.HighlightColor; ActiveShadow = SelectedItem.ShadowColor; } So, the objective is to call UpdateStyle() whenever selectedchanged event is fired. So in the .CS file, i call UpdateStyle(). The problem is, whenever I get into the selectionchanged event method, my ViewModel.SelectedItem is always null. I tried debugging this to see if the binding was working correctly, and it is. When I click on an item in the listbox, the SelectedItem Set is triggered, setting the value... but somewhere inbetween that and the selected changed (In the CS File) It gets reset to Null. Can anyone help out? Thanks

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  • SQL Where question

    - by needshelp
    Hi all, I have a question about case statements and nulls in a where clause. I want to do the following: Declare @someVar int = null select column1 from TestTable t where t = case when @someVar is not null then @someVar else t end Here is the problem: Let's say @someVar is null. Let's also say that column1 from TestTable t has NULL column values. Then, my condition t = t in the case statement will always evaluate to false. I basically just want to be able to conditionally filter the column based on the value of @someVar if it's provided. Any help?

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  • JDBC Null pointer Exception thrown

    - by harigm
    Hi I'm getting nullpointerexception at rs.next() or rs.getString(1) it is really weird that sometimes rs.next() works fine and it throws nullpointerexception at rs.getString("PRODUCTCODE"),sometimes it throws npe at rs.getString("PRODDATE") i dont understand why rs.getString() thows npe while rs.next() works fine Here is my code { ResultSet rs = null; String query = ""; BarcodeBean bi = null; try { query = "SELECT * FROM TABLE(GET_BARCODEINFO('"barcode.trim()"'))"; statement = connection.createStatement(); Logger.getInstance().getLogger().logInfo(query); rs = statement.executeQuery(query); bi = new BarcodeBean(); if (rs == null){ if(rs.next()){ bi.setUrunKodu(rs.getString("PRODUCTCODE")); bi.setImalatMakineKodu(rs.getString("PRODMACHINECODE")); bi.setOperatorSicilNo(rs.getString("OPERATORID")); bi.setImalatTarihi(rs.getString("PRODDATE")); bi.setImalatVardiyasi(rs.getString("PRODSHIFT")); bi.setSeriNumarasi(rs.getString("SERIALNUMBER")); bi.setSirtTarihi(rs.getString("SIRTTARIHI")); } } } catch (SQLException e) { e.printStackTrace(); throw e; } catch (Exception e) { e.printStackTrace(); } finally { DatabaseUtility.close(rs); DatabaseUtility.close(statement); } }

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  • ASP.NET MVC 2 RC2 Model Binding with NVARCHAR NOT NULL column

    - by Gary McGill
    I have a database column defined as NVARCHAR(1000) NOT NULL DEFAULT(N'') - in other words, a non-nullable text column with a default value of blank. I have a model class generated by the Linq-to-SQL Classes designer, which correctly identifies the property as not nullable. I have a TextAreaFor in my view for that property. I'm using UpdateModel in my controller to fetch the value from the form and populate the model object. If I view the web page and leave the text area blank, UpdateModel insists on setting the property to NULL instead of empty string. (Even if I set the value to blank in code prior to calling UpdateModel, it still overwrites that with NULL). Which, of course, causes the subsequent database update to fail. I could check all such properties for NULL after calling UpdateModel, but that seems ridiculous - surely there must be a better way? Please don't tell me I need a custom model binder for such a simple scenario...!

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