c++ - Why QTcpSocket received wrong data? -

-

i'm writing simple network application. client sending server message server printing in qtextedit , responding client . i'm using qtcpserver , qtcpsocket. there problem can't solve. receiving data quint16 + qtime + qstring sending qbytearrey. use quint16 receiving size of data blocks. , reason when client send server

next block size: 16 (quint16 value) block size: 18

server get:

next block size: 30073  (quint16 value) block size: 18

as can see, reason server getting qdatastrem wrong variable value , 30073. don't understand why?

void widget::slotsendtoserver() {     logtextedit->append("slotsendtoserver()");     qbytearray arrblock;     qdatastream serversendstream(&arrblock, qiodevice::readwrite);     qstring messagestr = messagelineedit->text();      serversendstream << quint16(0) << qtime::currenttime()                      << messagestr;      serversendstream.device()->seek(0);     serversendstream << (quint16)(arrblock.size() - sizeof(quint16));      qdebug() << "next_block_size:"              <<(quint16)(arrblock.size() - sizeof(quint16))               << endl              << "full size of byte arrey:" << arrblock.size();      tcpsocket->write(arrblock);     messagelineedit->clear(); }    void widget::slotreadclient() {     logtextedit->append("slotreadclient()");     qtcpsocket *tcpsocket = (qtcpsocket*)sender();     qdatastream clientreadstream(tcpsocket);      while(true)     {         if (!next_block_size)         {             if (tcpsocket->bytesavailable() < sizeof(quint16))             {                 break;             }             clientreadstream >> next_block_size;         }          if (tcpsocket->bytesavailable() < next_block_size)         {             break;         }         qtime   time;         qstring messagetextstr;         clientreadstream >> time >> messagetextstr;          qstring messagecompletestr =                 time.tostring() + " " + "client has sent - "                                  + messagetextstr;         logtextedit->append("message received: ");         logtextedit->append(messagecompletestr);          next_block_size = 0;          sendtoclient(tcpsocket,                      "server response: received \""                        + messagetextstr + "\"");     } }

you should ensure variable next_block_size initialized 0 each time socket connected.

if don't reuse same qtcpsocket object, can done in widget class constructor, or if do, in slot connected signal connected().


Comments

Post a Comment

Popular posts from this blog

c++ - list<myClass<int> * > sort -

-
i cannot sort list contains pointers objects of template class. template class node{ public: node(void){} node(t choice, vector<t> & data); node(t choice, vector<t> & data, player p, int level, int pos, node<t> *pred, side); void addnodes(void); static list<node<t> * > nodes; friend class mybinomialtree<node<t>, t>; bool sorter(const node<t> * lhs, const node<t> * rhs);// * &lhs doesn't work private: node<t> * left; node<t> * right; t chosen_; vector<t> data_; bool isleaf; //... }; outside class: template<class t> bool node<t>::sorter(const node<t> * lhs, const node<t> * rhs){ if((*lhs).level_==(*rhs).level_){ return (*lhs).pos_<(*rhs).pos_; }else{ return (*lhs).level_<(*rhs).level_; } } and want sort before print, have template<class t> void node<t>::print(void){ ...
Read more

SoapUI on windows 10 - high DPI/4K scaling issue -

-
Image
soapui doesn't seem dpi-aware , displays small on high dpi screen (tiny text , buttons). other applications running fine (screen resolution 3840 x 2160). version : soapui 5.1.2 os : windows 10 i have tried: configure soapui run "disable display scaling on high dpi settings" - parts of soapui looking bigger , don't display (image) changing resolution changing font size (preferences > editor settings > select font...) therefore assume, soapui pretends dpi-aware, not scale itself. have same issue? this workaround until developers round making version dpi-aware. step 1: add registry key hkey_local_machine\software\microsoft\windows\currentversion\sidebyside\preferexternalmanifest (dword) 1 step 2: add manifest file 'soapui-5.2.1.exe.manifest' in same directory 'soapui-5.2.1.exe' content of manifest file: <?xml version="1.0" encoding="utf-8" standalone="yes"?> <assembly xml...
Read more

java - why am i getting a "cannot resolve method" error on getApplication? -

-
i believe have code in order ive been toiling on error few hours now. im trying setup basic app framework using fragments. can code work if structure project activity based , put string data along block of code below in mainactivity, doesnt me try move them fragments. in mainactivity (where same block of code works without using fragments) placed in oncreate makes no difference if place there in fragment , read placing in oncreate not proper place. im new android development, if explain answer code example greatly. thank taking time look. my entire fragment below. public class basicspagefragment extends fragment { recyclerview recyclerview; private recycler_view_adapter adapter; public basicspagefragment() { // required empty public constructor } @override public void oncreate(bundle savedinstancestate) { } @override public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) { // inflate layou...
Read more