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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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  • Help with malloc and free: Glibc detected: free(): invalid pointer

    - by nunos
    I need help with debugging this piece of code. I know the problem is in malloc and free but can't find exactly where, why and how to fix it. Please don't answer: "Use gdb" and that's it. I would use gdb to debug it, but I still don't know much about it and am still learning it, and would like to have, in the meanwhile, another solution. Thanks. #include <stdio.h> #include <stdlib.h> #include <ctype.h> #include <unistd.h> #include <string.h> #include <sys/wait.h> #include <sys/types.h> #define MAX_COMMAND_LENGTH 256 #define MAX_ARGS_NUMBER 128 #define MAX_HISTORY_NUMBER 100 #define PROMPT ">>> " int num_elems; typedef enum {false, true} bool; typedef struct { char **arg; char *infile; char *outfile; int background; } Command_Info; int parse_cmd(char *cmd_line, Command_Info *cmd_info) { char *arg; char *args[MAX_ARGS_NUMBER]; int i = 0; arg = strtok(cmd_line, " "); while (arg != NULL) { args[i] = arg; arg = strtok(NULL, " "); i++; } num_elems = i;precisa em free_mem if (num_elems == 0) return 0; cmd_info->arg = (char **) ( malloc(num_elems * sizeof(char *)) ); cmd_info->infile = NULL; cmd_info->outfile = NULL; cmd_info->background = 0; bool b_infile = false; bool b_outfile = false; int iarg = 0; for (i = 0; i < num_elems; i++) { if ( !strcmp(args[i], "<") ) { if ( b_infile || i == num_elems-1 || !strcmp(args[i+1], "<") || !strcmp(args[i+1], ">") || !strcmp(args[i+1], "&") ) return -1; i++; cmd_info->infile = malloc(strlen(args[i]) * sizeof(char)); strcpy(cmd_info->infile, args[i]); b_infile = true; } else if (!strcmp(args[i], ">")) { if ( b_outfile || i == num_elems-1 || !strcmp(args[i+1], ">") || !strcmp(args[i+1], "<") || !strcmp(args[i+1], "&") ) return -1; i++; cmd_info->outfile = malloc(strlen(args[i]) * sizeof(char)); strcpy(cmd_info->outfile, args[i]); b_outfile = true; } else if (!strcmp(args[i], "&")) { if ( i == 0 || i != num_elems-1 || cmd_info->background ) return -1; cmd_info->background = true; } else { cmd_info->arg[iarg] = malloc(strlen(args[i]) * sizeof(char)); strcpy(cmd_info->arg[iarg], args[i]); iarg++; } } cmd_info->arg[iarg] = NULL; return 0; } void print_cmd(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("infile=\"%s\"\n", cmd_info->infile); printf("outfile=\"%s\"\n", cmd_info->outfile); printf("background=\"%d\"\n", cmd_info->background); } void get_cmd(char* str) { fgets(str, MAX_COMMAND_LENGTH, stdin); str[strlen(str)-1] = '\0'; } pid_t exec_simple(Command_Info *cmd_info) { pid_t pid = fork(); if (pid < 0) { perror("Fork Error"); return -1; } if (pid == 0) { if ( (execvp(cmd_info->arg[0], cmd_info->arg)) == -1) { perror(cmd_info->arg[0]); exit(1); } } return pid; } void type_prompt(void) { printf("%s", PROMPT); } void syntax_error(void) { printf("msh syntax error\n"); } void free_mem(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) free(cmd_info->arg[i]); free(cmd_info->arg); free(cmd_info->infile); free(cmd_info->outfile); } int main(int argc, char* argv[]) { char cmd_line[MAX_COMMAND_LENGTH]; Command_Info cmd_info; //char* history[MAX_HISTORY_NUMBER]; while (true) { type_prompt(); get_cmd(cmd_line); if ( parse_cmd(cmd_line, &cmd_info) == -1) { syntax_error(); continue; } if (!strcmp(cmd_line, "")) continue; if (!strcmp(cmd_info.arg[0], "exit")) exit(0); pid_t pid = exec_simple(&cmd_info); waitpid(pid, NULL, 0); free_mem(&cmd_info); } return 0; }

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  • Return pointer to nested inner class from generic outer class

    - by helixed
    I'm new to C++, so bear with me. I have a generic class called A. A has a nested class called B. A contains a method called getB(), which is supposed to return a new instance of B. However, I can't get my code to compile. Here's what it looks like:#include A.h template <class E> class A { public: class B { public: int data; }; B * getB(); }; A.cpp #include "A.h" template <class E> A<E>::B * A::getB() { return new B(); } When I try to compile this, I get the following error: error: expected constructor, destructor, or type conversion before '*' token Does anybody know what I'm doing wrong? Thanks, helixed

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  • Objective-C Pointer to class that implements a protocol

    - by Winder
    I have three classes which implement the same protocol, and have the same parent class which doesn't implement the protocol. Normally I would have the protocol as pure virtual functions in the parent class but I couldn't find an Objective-C way to do that. How can I utilize polymorphism on these subclasses and call the functions implemented in the protocol without warnings? Some pseudocode if that didn't make sense: @interface superclass: NSObject {} @interface child1: superclass<MyProtocol> {} @interface child2: superclass<MyProtocol> {} The consumer of these classes: @class child1 @class child2 @class superclass @interface SomeViewController: UIViewController { child1 *oneView; child2 *otherView; superclass *currentView; } -(void) someMethod { [currentView protocolFunction]; } The only nice way I've found to do pure virtual functions in Objective-C is a hack by putting [self doesNotRecognizeSelector:_cmd]; in the parent class, but it isn't ideal.

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  • Parameter passing become pointer for integer

    - by Kangkan
    I am working on a c/Linux app for a device. I consume a web service (in WCF/c#) and use gSOAP for the same. The issue is that the parameters in the service methods become pointers for simple data types like int, short etc also. I initially used the same service exposed as ASMX web service and the client proxy generated using gSOAP created methods with parameters passed as values. But once the service has been upgraded to WCF, all the parameters became pointers. Can somebody help?

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  • Return a pointer to a char array in C

    - by snitko
    I've seen a lot of questions on that on StackOverflow, but reading the answers did not clear that up for me, probably because I'm a total newbie in C programming. Here's the code: #include <stdio.h> char* squeeze(char s[], char c); main() { printf("%s", squeeze("hello", 'o')); } char* squeeze(char s[], char c) { int i, j; for(i = j = 0; s[i] != '\0'; i++) if(s[i] != c) s[j++] = s[i]; s[j] = '\0'; return s; } It compiles and I get segmentation fault when I run it. I've read this faq about about returning arrays and tried the 'static' technique that is suggested there, but still could not get the program working. Could anyone point out exactly what's wrong with it and what should I be paying attention in the future?

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  • Convert "this" to a reference-to-pointer

    - by Austin Hyde
    Just stumbled onto this problem. (title says it all) Let's say I have a struct struct Foo { void bar () { do_baz(this); } void do_baz(Foo*& pFoo) { pFoo->p_sub_foo = new Foo; // for example } Foo* p_sub_foo; } GCC tells me that temp.cpp: In member function ‘void Foo::bar()’: temp.cpp:3: error: no matching function for call to ‘Foo::do_baz(Foo* const)’ temp.cpp:5: note: candidates are: void Foo::do_baz(Foo*&) So, how do I convert what is apparently a const Foo* to a Foo*&?

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  • Bit shift and pointer oddities in C, looking for explanations

    - by foo
    Hi all, I discovered something odd that I can't explain. If someone here can see what or why this is happening I'd like to know. What I'm doing is taking an unsigned short containing 12 bits aligned high like this: 1111 1111 1111 0000 I then want to shif the bits so that each byte in the short hold 7bits with the MSB as a pad. The result on what's presented above should look like this: 0111 1111 0111 1100 What I have done is this: unsigned short buf = 0xfff; //align high buf <<= 4; buf >>= 1; *((char*)&buf) >>= 1; This gives me something like looks like it's correct but the result of the last shift leaves the bit set like this: 0111 1111 1111 1100 Very odd. If I use an unsigned char as a temporary storage and shift that then it works, like this: unsigned short buf = 0xfff; buf <<= 4; buf >>= 1; tmp = *((char*)&buf); *((char*)&buf) = tmp >> 1; The result of this is: 0111 1111 0111 1100 Any ideas what is going on here?

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  • Passing pointer position to an object in Java.

    - by Gabriel A. Zorrilla
    I've got a JPanel class called Board with a static subclass, MouseHanlder, which tracks the mouse position along the appropriate listener in Board. My Board class has fields pointerX and pointerY. How do i pass the e.getX() and e.getY() from the MouseHandler subclass to its super class JPanel? I tried with getters, setters, super, and cant get the data transfer between subclass and parent class. I'm certain it's a concept issue, but im stuck. Thanks!

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  • Initialize Pointer Through Function

    - by SoulBeaver
    I was browsing my teacher's code when I stumbled across this: Order* order1 = NULL; then order1 = order(customer1, product2); which calls Order* order(Customer* customer, Product* product) { return new Order(customer, product); } This looks like silly code. I'm not sure why, but the teacher initialized all pointers to NULL instead of declaring them right away(looking at the code it's entirely possible, but he chose not to). My question is: is this good or acceptable code? Does the function call have any benefits over calling a constructor explicitely? And how does new work in this case? Can I imagine the code now as kind of like: order1 = new Order(customer, product);

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  • Function pointer arrays in Fortran

    - by Eduardo Dobay
    I can create function pointers in Fortran 90, with code like real, external :: f and then use f as an argument to another function/subroutine. But what if I want an array of function pointers? In C I would just do double (*f[])(int); to create an array of functions returning double and taking an integer argument. I tried the most obvious, real, external, dimension(3) :: f but gfortran doesn't let me mix EXTERNAL and DIMENSION. Is there any way to do what I want? (The context for this is a program for solving a system of differential equations, so I could input the equations without having a million parameters in my subroutines.)

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  • dynamic array pointer to binary file

    - by Yijinsei
    Hi guys, Know this might be rather basic, but I been trying to figure out how to one after create a dynamic array such as double* data = new double[size]; be used as a source of data to be kept in to a binary file such as ofstream fs("data.bin",ios:binary"); fs.write(reinterpret_cast<const char *> (data),size*sizeof(double)); When I finish writing, I attempt to read the file through double* data = new double[size]; ifstream fs("data.bin",ios:binary"); fs.read(reinterpret_cast<char*> (data),size*sizeof(double)); However I seem to encounter a run time error when reading the data. Do you guys have any advice how i should attempt to write a dynamic array using pointers passed from other methods to be stored in binary files?

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  • Null Pointer Exception while using Java Compiler API

    - by java_geek
    MyClass.java: package test; public class MyClass { public void myMethod(){ System.out.println("My Method Called"); } } Listing for SimpleCompileTest.java that compiles the MyClass.java file. SimpleCompileTest.java: package test; import javax.tools.*; public class SimpleCompileTest { public static void main(String[] args) { String fileToCompile = "test" + java.io.File.separator +"MyClass.java"; JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); int compilationResult = compiler.run(null, null, null, fileToCompile); if(compilationResult == 0){ System.out.println("Compilation is successful"); }else{ System.out.println("Compilation Failed"); } } } I am executing the SimpleCompileTest class and getting a NullPointerException. The ToolProvider.getSystemJavaCompiler() is returning null. Can someone tell me what is wrong with the code

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  • Function pointer demo

    - by AKN
    Hi, Check the below code void functionptrdemo() { typedef int *(funcPtr) (int,int); funcPtr ptr; ptr = add; //IS THIS CORRECT? (*ptr)(2,3); } In the place where I try to assign a function to function ptr with same function signature, it shows a compilation error as error C2659: '=' : function as left operand

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  • Conversion of pointer-to-pointer between derived and base classes?

    - by Mike Mueller
    Regarding the following C++ program: class Base { }; class Child : public Base { }; int main() { // Normal: using child as base is allowed Child *c = new Child(); Base *b = c; // Double pointers: apparently can't use Child** as Base** Child **cc = &c; Base **bb = cc; return 0; } GCC produces the following error on the last assignment statement: error: invalid conversion from ‘Child**’ to ‘Base**’ My question is in two parts: Why is there no implicit conversion from Child** to Base**? I can make this example work with a C-style cast or a reinterpret_cast. Using these casts means throwing away all type safety. Is there anything I can add to the class definitions to make these pointers cast implicitly, or at least phrase the conversion in a way that allows me to use static_cast instead?

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  • How to gain Access to member variables of a class using void pointer but Not Object

    - by mahesh
    Hi, I am trying to access member variables of a class without using object. please let me know how to go about. class TestMem { int a; int b; public: TestMem(){} void TestMem1() { a = 10; b = 20; } }; void (TestMem::*pMem)(); int main(int argc, char* argv[]) { TestMem o1; pMem = &(TestMem::TestMem1); void *p = (void*)&pMem; // How to access a & b member variables using variable p getch(); return 0; }

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  • wrapp a function whose parameters are out type pointer to structure using swig

    - by pierr
    I have following function : typedef struct tagT{ int a ; int b ; }Point; int lib_a_f_5(Point *out_t) { out_t->a = 20; out_t->b = 30; return 0; } How should I direct the SWIG to generate the correct code for ruby (or lua)? When putting following statement to the interface file : %apply SWIGTYPE Point* {Point *out_t}; I got a warning : liba.i:7: Warning(453): Can't apply (Point *OUTPUT). No typemaps are defined. Did i need to write a typemap? How should I do it?

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  • puts() a pointer in C

    - by Sergey Gavruk
    I have a function: char *make_text(void) { char txt[MAXLEN]; //make something return txt; } Thats my main program: int main(void) { char *s = make_text(); puts(s); getch(); return 0; } puts(s) returns 0 and its nothing printed. Whats happened?

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  • Mouse pointer plug in

    - by user171523
    I am developing a website where i am using CSS based layouts with absoulate positions. I would like to know is there any plug in for IE 8 which will tell based on the mouse where i am moving with the position (In Pixels). I want to know with out any JS. I am looking is there any external plug in which will allow me to find out the position.

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