openSUSE Programming September 2004

programming@lists.opensuse.org

40 participants
59 discussions

by Gustavo Dutra

Hi, I have been trying with no success to create a java kde project in kdevelop (kde 3.3 - suse 9.0) It aborts with "can't create file subdirs" message. Any clues? Thanks in advance!!

17 years, 9 months

Rusty oldtimer (newbie now) in gcc programming kindly ask for help

by Robert Rozman

Hi, I'm speech recognition researcher not so fond of newer Linux systems. I have some old ansi C code that I used to run under Debian 2.0. Now I transferred code to Suse 9.0, compile it without any errors (some warnings) but get segmentation faults in runtime. One particular error is (I get this when run in ddd): Program received signal SIGSEGV, Segmentation fault. 0x400b90af in fflush() from /lib/libc.so.6 ---------------- My C knowledge is rusty (I checked up this code long time ago) so I'd kindly ask for some quick guidance, how to deal with such segfaults. If I remember right there were some tools that could help in debugging memory accesses (efence or something like that) - I guess tools are now much more advanced - but I don't know which one to use... Also any advice on this particular error would be appreciated. Thanks in advance, regards, Robert.

17 years, 9 months

Displaying an image file with QImage

by Prabu Subroto

Dear my friends... I use SuSE 9.1 and Qt 3.2 . I am writing a database program with Qt. I have an image file named "1.png", I want this image file displayed in a Dialog Form. Anybody would be so generous to give me a very simple sample code how to display an image file into a Dialog Form with QImage? All I know only this step : QImage::QImage("images/1.png"); Please give me a very simple sample code. Thank you very much in advance. _______________________________ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com

17 years, 9 months

Can't compile Maelstrom from SRPM

by Chris W

I am trying to make a few modifications to Maelstrom I have applied all the patches from suse to the Maelstrom code and get the following error during configure. *** The sdl-config script installed by SDL could not be found *** If SDL was installed in PREFIX, make sure PREFIX/bin is in *** your path, or set the SDL_CONFIG environment variable to the *** full path to sdl-config. configure: error: *** SDL version 1.0.0 not found! I also thought the following output might help to figure out the problem > rpm -qa|grep SDL SDL-1.2.5-259 SDL_ttf-2.0.6-105 SDL_perl-1.20.0-236 SDL_image-1.2.3-105 SDL_mixer-1.2.5-90 SDL_net-1.2.5-103 > rpm -ql SDL /usr/lib/libSDL-1.2.so.0 /usr/lib/libSDL-1.2.so.0.0.5 This is on an suse 9.0 installation. I am not very familiar with all the compiler tools so I could really use some help here. -- Chris W Bring Back the HP 15C http://hp15c.org Not getting the gifts you want? The Wish Zone can help. http://thewishzone.com

17 years, 9 months

Re: [suse-programming-e] Q4 ppl/w both C++ and Java experience

by John Lamb

Jerry Feldman wrote: >> 1. mutexed blocks (why does java call them 'synchronized' when they >> can't happen at the same time?) > Mutex is simply one terminology for a "synchronization primitive". > Semaphore is also used. There are other terminologies used in various > other implementations of things. I was just being ironic. Java is a moralistic language and insists on using final instead of const to avoid the oxymoron of a constant variable; so I think it ought to use asynchronized instead of synchronized to avoid the oxymoron of a synchronized block that cannot be run at the same time as any other synchronised block. I accept of course, that it's common practice to use such expressions. Hotplugging is another term that comes to mind. I know you can emulate this using a base class like the following, but it's still a bit clunky and error prone: class Monitor { public: Monitor(){ mutex = (pthread_mutex_t*)malloc( sizeof(pthread_mutex_t) ); pthread_mutex_init( mutex, 0 ); } virtual ~Monitor() = 0; void lock() const { pthread_mutex_lock( mutex ); } void unlock() const { pthread_mutex_unlock( mutex ); } private: mutable pthread_mutex_t* mutex; }; Monitor::~Monitor(){ free(mutex); } I like the idea of GC in C++ and IIRC an compiler implememntation may use GC. -- JDL

17 years, 9 months

mailing list for GNU C++ (gcc)

by Prabu Subroto

Dear my beloved friends... Anybody would be so nice to tell me the mailing list of GCC? I want to practice this programming language deeper. Thank you very much in advance. __________________________________ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail

17 years, 9 months

C++ curtiosity: default argument in a pointer to function.

by John Lamb

This compiles and works under gcc 3.3.3, but I suspect it's not legal because I'm giving a default argument to a pointer to a function. Can anyone tell me if I'm right or wrong? #include<iostream> double function( double x, double y = 0 ){ return x * (x + y); } int main() { double (*function)( double, double = 0 ) = ::function; std::cout << function( 4 ) << std::endl; exit( 0 ); } -- JDL

17 years, 9 months

passing the value of a string varible to another form (ui form).

by Prabu Subroto

Dear my friends... I retrieve a list of customer that the sales of my company have to be followed up by the sales. This retrievement is done in the funonseqForm.ui. and the object which does this task is QDataBrowser (custdataBrowser). I created a form to make a selection mechanism for a the funonseqForm is from caricustForm.ui . the caricustForm generate the sql string for custdataBrowser. The SQL String (QString myfilter) should be passed to the funonseqForm as the filter of custdataBrowser ( custdataBrowser->setfilter(myfilter); ). Firstly I did like this : funonseqForm::custdataBrowser->setFilter(kalimat); But of course it's wrong. I got problem in compiling process. I am looking for the procedure/method how the ui forms communicating each other to handle the variable value from another ui form (passing or getting the value of a varible from another ui form). Thank you very much in advance. ===== void caricustForm::cariSlot() { QString pilih, kalimat; QString prsh = prshlineEdit->text(); QString salut = salutcomboBox->currentText(); QString title = titlelineEdit->text(); QString fn = firstnamelineEdit->text(); QString ln = lastnamelineEdit->text(); QString alamat = addresslineEdit->text(); QString kodepos = postcodelineEdit->text(); QString kota = kotalineEdit->text(); QString kodekota = areacodelineEdit->text(); QString telepon = teleponlineEdit->text(); QString hp = hplineEdit->text(); QString fax = faxlineEdit->text(); QString email = emaillineEdit->text(); if ( prsh.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " company like '%"; kalimat += QString("%1").arg(prsh); kalimat += "% "; } if ( salut.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " salutation like '%"; kalimat += QString("%1").arg(salut); kalimat += "% "; } if ( title.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " title like '%"; kalimat += QString("%1").arg(title); kalimat += "% "; } if ( fn.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " firstname like '%"; kalimat += QString("%1").arg(fn); kalimat += "% "; } if ( ln.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " lastname like '%"; kalimat += QString("%1").arg(ln); kalimat += "% "; } if ( alamat.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " address like '%"; kalimat += QString("%1").arg(alamat); kalimat += "% "; } if ( kodepos.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " postcode like '%"; kalimat += QString("%1").arg(kodepos); kalimat += "% "; } if ( kota.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " city like '%"; kalimat += QString("%1").arg(kota); kalimat += "% "; } if ( kodekota.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " areacode like '%"; kalimat += QString("%1").arg(kodekota); kalimat += "% "; } if ( telepon.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " phone like '%"; kalimat += QString("%1").arg(telepon); kalimat += "% "; } if ( hp.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " mobilephone like '%"; kalimat += QString("%1").arg(hp); kalimat += "% "; } if ( fax.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " fax like '%"; kalimat += QString("%1").arg(fax); kalimat += "% "; } if ( email.length() > 0 ){ if (kalimat.length() > 0){ kalimat += " or "; } kalimat += " email like '%"; kalimat += QString("%1").arg(email); kalimat += "% "; } liattextEdit->setText(kalimat); funonseqForm::custdataBrowser->setFilter(kalimat); } __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail

17 years, 9 months

OS C++ Exception interoperation?

by Steven T. Hatton

Is there a similar facility in Linux for exception "exception registration"? http://www.codeproject.org/cpp/exceptionhandler.asp#xx515459xx For this discussion, I will consider exceptions to be those that are explicitly thrown or occur due to conditions like divide by zero or null pointer access. When exception occurs, interrupt is generated and control is transferred to the operating system. Operating System, in turn, calls the exception handler that inspects the function call sequence starting from the current function from where the exception originated, and performs its job of stack unwinding and control transfer. We can write our own exception handler and register it with the operating system that it would call in the event of an exception. Windows defines a special structure for registration, called EXCEPTION_REGISTRATION: -- Regards, Steven

17 years, 9 months

My program (written in Qt) suddenly shut down (crashed)

by Prabu Subroto

Dear my friends... I am using SuSE 9.1 and Qt 3.2. I wrote a program. compiled successfully. But it doesn't run more than 3 minutes. It simply crashed after around 3 minutes. I use "ddd" to find where it crashes. Here is the output of my ddd: Dump of assembler code for function _ZNK12QSqlDatabase6isOpenEv: 0x405019f0 <QSqlDatabase::isOpen() const+0>: push %ebp 0x405019f1 <QSqlDatabase::isOpen() const+1>: mov %esp,%ebp 0x405019f3 <QSqlDatabase::isOpen() const+3>: push %ebx 0x405019f4 <QSqlDatabase::isOpen() const+4>: sub $0x4,%esp 0x405019f7 <QSqlDatabase::isOpen() const+7>: mov 0x8(%ebp),%eax 0x405019fa <QSqlDatabase::isOpen() const+10>: call 0x401e0beb <__i686.get_pc_thunk.bx> 0x405019ff <QSqlDatabase::isOpen() const+15>: add $0x2054f5,%ebx 0x40501a05 <QSqlDatabase::isOpen() const+21>: mov 0x28(%eax),%eax 0x40501a08 <QSqlDatabase::isOpen() const+24>: mov (%eax),%eax 0x40501a0a <QSqlDatabase::isOpen() const+26>: mov %eax,(%esp) 0x40501a0d <QSqlDatabase::isOpen() const+29>: call 0x401b8e14 <_init+47544> 0x40501a12 <QSqlDatabase::isOpen() const+34>: pop %ecx 0x40501a13 <QSqlDatabase::isOpen() const+35>: movzbl %al,%eax 0x40501a16 <QSqlDatabase::isOpen() const+38>: pop %ebx 0x40501a17 <QSqlDatabase::isOpen() const+39>: pop %ebp 0x40501a18 <QSqlDatabase::isOpen() const+40>: ret 0x40501a19 <QSqlDatabase::isOpen() const+41>: nop 0x40501a1a <QSqlDatabase::isOpen() const+42>: lea 0x0(%esi),%esi End of assembler dump. The error message is : Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 16384 (LWP 4934)] 0x40501a08 in QSqlDatabase::isOpen () from /usr/lib/libqt-mt.so.3 I found from ddd the crash happened on this line " Current program counter (stopped by signal) : 0x40501a08 <QSqlDatabase::isOpen() const+24>: mov (%eax),%eax " Why is it happenned? Please tell me. =========== #Here is my code where the crash bool depanForm::cariappSlot() { int sid, cid; QString applist, pesan; unsigned int noapp; //if ( ! db->isOpen() ){ // konekSlot(); //} if ( !un ){ QString lines; QFile file( "otentik.txt" ); if ( file.open( IO_ReadOnly ) ) { QTextStream stream( &file ); QString line; //int i = 1; while ( !stream.atEnd() ) { line = stream.readLine(); // line of text excluding '\n' //printf( "%3d: %s\n", i++, line.latin1() ); lines += line; } file.close(); } //baca username dan paswordnya extunpwSlot(lines); } QSqlDatabase * db = QSqlDatabase::addDatabase("QPSQL7", "OTHER"); db->setHostName("192.168.23.1"); db->setDatabaseName("kv"); db->setUserName("postgres"); db->setPassword("honestly"); if ( ! db->open() ) { db->lastError().showMessage(); return false; } QSqlQuery query(db); QString sqloten = QString("select SalesID from useraccount where Username='%1' and Password='%1'") .arg(un) .arg(pw); query.prepare(sqloten); query.exec(); if ( ! query.isActive() ){ query.lastError().showMessage(); return false; }else{ while ( query.next() ){ sid = query.value(0).toInt(); } } appdate = QDate::currentDate(); apptime = QTime::currentTime(); applist = QString("v_applist_%1").arg(un); sqlcekapp = QString("select noapp, custid from %1 where salesid='%1' and date='%1' and time='%1' and warned='N' limit 1") .arg(applist) .arg(sid) .arg(appdate.toString("yyyy-MM-dd")) .arg(apptime.toString("hh:mm:ss")); QSqlQuery querycekapp(db); querycekapp.prepare(sqlcekapp); querycekapp.exec(); if ( ! querycekapp.isActive() ){ querycekapp.lastError().showMessage(); return false; } if ( querycekapp.next() ){ noapp = querycekapp.value(0).toInt(); cid = querycekapp.value(1).toInt(); pesan = QString("Sie haben ein Termin mit Kundennummer : %1") .arg(cid); QMessageBox::warning(this, "Achtung !", pesan); updatewarnedSlot(noapp); }else{ //if ( ! db->isOpen() ){ // konekSlot(); //} appdate = QDate::currentDate(); apptime = QTime::currentTime(); sqlcekapp = QString("select noapp, custid from %1 where salesid='%1' and (date<='%1' or ( date = '%1' and time<='%1' )) and warned='N' limit 1") .arg(applist) .arg(sid) .arg(appdate.toString("yyyy-MM-dd")) .arg(appdate.toString("yyyy-MM-dd")) .arg(apptime.toString("hh:mm:ss")); QSqlQuery querycekapp(db); querycekapp.prepare(sqlcekapp); querycekapp.exec(); if ( ! querycekapp.isActive() ){ querycekapp.lastError().showMessage(); return true; } if ( querycekapp.next() ){ noapp = querycekapp.value(0).toInt(); cid = querycekapp.value(1).toInt(); pesan = QString("Sie haben ein Termin mit Kundennummer %1 verpassen") .arg(cid); QMessageBox::warning(this, "Achtung !", pesan); updatewarnedSlot(noapp); } } return true; } _______________________________ Do you Yahoo!? Shop for Back-to-School deals on Yahoo! Shopping. http://shopping.yahoo.com/backtoschool

17 years, 9 months

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openSUSE Programming September 2004