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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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  • 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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  • boost::dynamic_pointer_cast with const pointer not working ?

    - by ereOn
    Hi, Let's say I have two classes, A and B, where B is a child class of A. I also have the following function: void foo(boost::shared_ptr<const A> a) { boost::shared_ptr<const B> b = boost::dynamic_pointer_cast<const B>(a); // Error ! } Compilation with gcc gives me the following errors: C:\Boost\include/boost/smart_ptr/shared_ptr.hpp: In constructor 'boost::shared_ptr< <template-parameter-1-1> >::shared_ptr(const boost::shared_ptr<Y>&, boost::detail::dynamic_cast_tag) [with Y = const A, T = const B]': C:\Boost\include/boost/smart_ptr/shared_ptr.hpp:522: instantiated from 'boost::shared_ptr<X> boost::dynamic_pointer_cast(const boost::shared_ptr<U>&) [with T = const B, U = const A]' src\a.cpp:10: instantiated from here C:\Boost\include/boost/smart_ptr/shared_ptr.hpp:259: error: cannot dynamic_cast 'r->boost::shared_ptr<const A>::px' (of type 'const class A* const') to type 'const class B*' (source type is not polymorphic) What could possibly be wrong ? Thank you.

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  • Release build in MVS 2010 professional v/s express for C

    - by yCalleecharan
    Hi, recently I discovered that "executing" a C program as a release build instead of a debug build optimizes the code and makes it run much faster. This is accessed through project properties configuration manager menu. I would like to know if this feature is the same in the professional version and the express edition of MVS 2010 in terms of speed optimization. I have the express edition. Also, I would like to know if C programs run with the same speed as in both the professional and express editions. I understand that the professional edition has many "software" tools for the serious programmer. Thanks a lot..

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  • pointer to member function question

    - by Steve
    Hello, I'm trying to replicate a template I've used before with a member function, and it isn't going very well. The basic form of the function is template<class T> T Convert( HRESULT (*Foo)(T*)) { T temp; Foo(&temp); //Throw if HRESULT is a failure return temp; } HRESULT Converter(UINT* val) { *val = 1; return S_OK; } int _tmain(int argc, _TCHAR* argv[]) { std::cout << Convert<UINT>(Converter) << std::endl; return 0; } For the life of me, I can't get this to work with a member variable. I've read up on their syntax, and I can't seem to figure out how to make it work with templates. The class would be something similar to class TestClass { HRESULT Converter(UINT* val) { *val = 1; return S_OK; } }

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  • pointer and reference question (linked lists)

    - by sil3nt
    Hi there, I have the following code struct Node { int accnumber; float balance; Node *next; }; Node *A, *B; int main() { A = NULL; B = NULL; AddNode(A, 123, 99.87); AddNode(B, 789, 52.64); etc… } void AddNode(Node * & listpointer, int a, float b) { // add a new node to the FRONT of the list Node *temp; temp = new Node; temp->accnumber = a; temp->balance = b; temp->next = listpointer; listpointer = temp; } in this here void AddNode(Node * & listpointer, int a, float b) { what does *& listpointer mean exactly.

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  • null pointer exception at org.hibernate.tuple.AbstractEntityTuplizer.createProxy

    - by saurabh
    I am using hibernate 3.2 with struts 1.2 framework I got this exception when i m trying to load the object I am using this code to load the object public Currentprofile findById(java.lang.String id) { log.debug("getting Currentprofile instance with id: " + id); try { Currentprofile instance = (Currentprofile) getSession().get( "com.hibermappings.Currentprofile", id); return instance; } catch (RuntimeException re) { log.error("get failed", re); throw re; } } my hbm file is this <one-to-one name="referenceDb" lazy="proxy" class="com.hibermappings.ReferenceDb" cascade="all" constrained="false" /> <one-to-one name="registration" lazy="proxy" class="com.hibermappings.Registration" cascade="all" constrained="false" /> <one-to-one name="jobseekerpackagedetails" lazy="proxy" class="com.hibermappings.Jobseekerpackagedetails" cascade="all" constrained="false" /> <property name="keyWords" type="java.lang.String"> <column name="keyWords" length="5000" /> </property> <property name="totalExp" type="java.lang.String"> <column name="totalExp" length="100" /> </property> <property name="hqualification" type="java.lang.String"> <column name="hQualification" length="100" /> </property> <property name="preferedLocation" type="java.lang.String"> <column name="preferedLocation" length="100" /> </property> <property name="functionalArea" type="java.lang.String"> <column name="functionalArea" length="1000" /> </property> <property name="expSalary" type="java.lang.String"> <column name="expSalary" length="100" /> </property> <property name="designation" type="java.lang.String"> <column name="designation" length="100" /> </property> <property name="resumeTitle" type="java.lang.String"> <column name="resumeTitle" length="500" /> </property> <property name="profileDetails" type="java.lang.String"> <column name="profileDetails" length="65535" /> </property> <property name="requiredProfile" type="java.lang.String"> <column name="requiredProfile" length="65535" /> </property> <property name="activatedOn" type="java.util.Date"> <column name="activatedOn" length="0" /> </property> <set name="resumes" inverse="true" cascade="save-update"> <key> <column name="jobseekerId" length="50" /> </key> <one-to-many class="com.hibermappings.Resume" /> </set> </class> the same code runs well when I m using in a simple java class within main method .. full stack trace of exception is java.lang.NullPointerException at org.hibernate.tuple.AbstractEntityTuplizer.createProxy(AbstractEntityTuplizer.java:372) at org.hibernate.persister.entity.AbstractEntityPersister.createProxy(AbstractEntityPersister.java:3121) at org.hibernate.event.def.DefaultLoadEventListener.createProxyIfNecessary(DefaultLoadEventListener.java:232) at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:173) at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87) at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862) at org.hibernate.impl.SessionImpl.load(SessionImpl.java:781) at org.hibernate.impl.SessionImpl.load(SessionImpl.java:774) at com.DAOs.CurrentprofileDAO.getLoad(CurrentprofileDAO.java:71) at com.action.JobSekeerManage.viewProfile(JobSekeerManage.java:447) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270) at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414) at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157) at com.filter.HibernateFilter.doFilter(HibernateFilter.java:24) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:825) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:731) at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:526) at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595) Error::null

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  • C Nested Structure Pointer Problem

    - by Halo
    I have a shared structure, and inside it a request structure: struct shared_data { pthread_mutex_t th_mutex_queue; struct request_queue { int min; int max; char d_name[DIR_SIZE]; pid_t pid; int t_index; } request_queue[BUFSIZE]; int count; int data_buffer_allocation[BUFSIZE]; int data_buffers[BUFSIZE][100]; }; Then I prepare a request; struct shared_data *sdata_ptr; ... ... sdata_ptr->request_queue[index].pid = pid; strcpy(sdata_ptr->request_queue[index].d_name, dir_path_name); sdata_ptr->request_queue[index].min = min; sdata_ptr->request_queue[index].max = max; And the compiler warns me that I'm doing an incompatible implicit declaration in the strcpy function. I guess that's a problem with the pointers, but isn't what I wrote above supposed to be true?

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  • some pointer to understanding GCC source code

    - by user299570
    hi, I'm student working on optimizing GCC for multi-core processor. I tried going through the source code, it is difficult to follow through it since I need to add some code to the back end. Can anyone suggest some good resource which explains the code flow through the different phases. Also suggest some development environment for debugging GCC mainly to step through the code. Is it possible on windows?

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  • C++: Unknown pointer size when forward declaring (error C2036)

    - by Rosarch
    In a header file, I have forward declared two members of a namespace: namespace Foo { struct Odp typedef std::vector<Odp> ODPVEC; }; class Bar { public: Foo::ODPVEC baz; // C2036 }; The error generated by the compiler is: error C2036: 'Foo::Odp *': unknown size I'm guessing this is an issue with forward declaring Odp. How can I get around this?

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  • Remove pointer object whose reference is mantained in three different lists

    - by brainydexter
    I am not sure how to approach this problem: 'Player' class mantains a list of Bullet* objects: class Player { protected: std::list< Bullet* > m_pBullet_list; } When the player fires a Bullet, it is added to this list. Also, inside the constructor of bullet, a reference of the same object is updated in CollisionMgr, where CollisionMgr also mantains a list of Bullet*. Bullet::Bullet(GameGL*a_pGameGL, Player*a_pPlayer) : GameObject( a_pGameGL ) { m_pPlayer = a_pPlayer; m_pGameGL->GetCollisionMgr()->AddBullet(this); } class CollisionMgr { void AddBullet(Bullet* a_pBullet); protected: std::list< Bullet*> m_BulletPList; } In CollisionMgr.Update(); based on some conditions, I populate class Cell which again contain a list of Bullet*. Finally, certain conditions qualify a Bullet to be deleted. Now, these conditions are tested upon while iterating through a Cell's list. So, if I have to delete the Bullet object, from all these places, how should I do it so that there are no more dangling references to it? std::list< Bullet*>::iterator bullet_it; for( bullet_it = (a_pCell->m_BulletPList).begin(); bullet_it != (a_pCell->m_BulletPList).end(); bullet_it++) { bool l_Bullet_trash = false; Bullet* bullet1 = *bullet_it; // conditions would set this to true if ( l_Bullet_Trash ) // TrashBullet( bullet1 ); continue; } Also, I was reading about list::remove, and it mentions that it calls the destructor of the object we are trying to delete. Given this info, if I delete from one list, the object does not exist, but the list would still contain a reference to it..How do I handle all these problems ? Can someone please help me here ? Thanks PS: If you want me to post more code or provide explanation, please do let me know.

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  • Reference to a pointer question

    - by Yogesh Arora
    Please refer to the code below. In this code i am storing the const char* returned by test.c_str() into a reference. My question is Will the data be correctly refering to the contents of test. I am thinking that ptr returned by test.c_str() will be a temporary and if i bound it to a reference that reference will not be valid. Is my thinking correct class RefPtrTest { std::string test; StoringClass storingClass; public: RefPtrTest(): test("hello"), storingClass(test.c_str()) { } } where StoringClass is class StoringClass { const char*& data; public: StoringClass (const char*& input): data(input) { } }

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  • Mockito upgrade causes null pointer problems

    - by Ann Addicks
    We upgraded from mockito-all-1.8.5.jar to mockito-all-1.9.0.jar and now see null pointers when using annotations for the classes being mocked. Here is an example: @Mock private static IAccountManager accountManager; @Mock private static IBusinessUnitManager businessUnitManager; private static Gson parser; @InjectMocks private static DownloadController downloadController; @BeforeClass public static void setUpBeforeClass() throws Exception { parser = new Gson(); downloadController = new DownloadController(accountManager, businessUnitManager, parser); } @Before public void setUp() throws Exception { MockitoAnnotations.initMocks(this); Mockito.reset(accountManager, businessUnitManager); } As soon as accountManager is referenced in the download controller, it throws a npe. This worked in 1.8.5.

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  • Compiler error when casting to function pointer

    - by detly
    I'm writing a bootloader for the PIC32MX, using HiTech's PICC32 compiler (similar to C90). At some point I need to jump to the real main routine, so somewhere in the bootloader I have void (*user_main) (void); user_main = (void (*) (void)) 0x9D003000; user_main(); (Note that in the actual code, the function signature is typedef'd and the address is a macro.) I would rather calculate that (virtual) address from the physical address, and have something like: void (*user_main) (void); user_main = (void (*) (void)) (0x1D003000 | 0x80000000); user_main(); ...but when I try that I get a compiler error: Error #474: ; 0: no psect specified for function variable/argument allocation Have I tripped over some vagarity of C syntax here? This error doesn't reference any particular line, but if I comment out the user_main() call, it goes away. (This might be the compiler removing a redundant code branch, but the HiTech PICC32 isn't particularly smart in Lite mode, so maybe not.)

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  • dangling pointer, reason for value change after free()?

    - by Aman Jain
    In the following code segment, after free(x), why does y becomes 0? As per my understanding, the memory in the heap that was being pointed to by x, and is still being pointed by y, hasn't been allocated to someone else, so how can it change to 0? And moreover, I don't think it is free(x) that changed it to 0. Any comments? #include <stdio.h> int main ( int argc, char *argv[] ) { int *y = NULL; int *x = NULL; x = malloc(4); *x = 5; y = x; printf("[%d]\n", *y); //prints 5 free(x); printf("[%d]\n", *y); //why doesn't print 5?, prints 0 instead return 0; }

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