Model/View weird behaviour - Windows/Mingw

[incapacitant]

Code 1, works. Code 2, aborts on launch (caught by Windows)

Code 1:

// destinataires
  qDestin = new QListView( this );
  qDestin->resize( QSize( 330, 110 ) ); 
  qDestin->move( 34, 71 );
 
  // setupModel
  model = new QStandardItemModel(0, 1, this);
  qDestin->setModel(model);
  qDestin->setSelectionMode( QListView::MultiSelection );

// destinataires
  qDestin = new QListView( this );
  qDestin->resize( QSize( 330, 110 ) ); 
  qDestin->move( 34, 71 );
      
  // setupModel
  model = new QStandardItemModel(0, 1, this);
  qDestin->setModel(model);
  qDestin->setSelectionMode( QListView::MultiSelection );

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Code 2:

// destinataires
  qDestin = new QListView( this );
  qDestin->resize( QSize( 330, 110 ) ); 
  qDestin->move( 34, 71 );
  qDestin->setModel(model);
  qDestin->setSelectionMode( QListView::MultiSelection );
 
  // setupModel
  model = new QStandardItemModel(0, 1, this);

// destinataires
  qDestin = new QListView( this );
  qDestin->resize( QSize( 330, 110 ) ); 
  qDestin->move( 34, 71 );
  qDestin->setModel(model);
  qDestin->setSelectionMode( QListView::MultiSelection );
      
  // setupModel
  model = new QStandardItemModel(0, 1, this);

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And code 2 generates no compile error from MINGW.


How can this be explained ?

[jpn]

How can this be explained ?

In code 1, you instantiate the model correctly before passing it to the view.
And in code 2 you pass an uninitialized pointer...

[jacek]

How can this be explained ?

In two words: unitialized pointer

PS. Do you have warnings enabled (CONFIG += warn_on)?

[incapacitant]

yes warn_on is there in C:\Qt\4.1.1\mkspecs\win32-g++\qmake.conf :

#
# qmake configuration for win32-g++
#
# Written for MinGW
#
 
MAKEFILE_GENERATOR    = MINGW
TEMPLATE        = app
CONFIG            += qt warn_on release link_prl copy_dir_files precompile_header
QT            += core gui
DEFINES            += UNICODE QT_LARGEFILE_SUPPORT
QMAKE_COMPILER_DEFINES  += __GNUC__ WIN32
 
QMAKE_EXT_OBJ           = .o
 
QMAKE_CC        = gcc
QMAKE_LEX        = flex

#
# qmake configuration for win32-g++
#
# Written for MinGW
#

MAKEFILE_GENERATOR    = MINGW
TEMPLATE        = app
CONFIG            += qt warn_on release link_prl copy_dir_files precompile_header
QT            += core gui
DEFINES            += UNICODE QT_LARGEFILE_SUPPORT
QMAKE_COMPILER_DEFINES  += __GNUC__ WIN32

QMAKE_EXT_OBJ           = .o

QMAKE_CC        = gcc
QMAKE_LEX        = flex

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As far as I know even Basic would complain about an undefined variable in code 2.
Or have I missed something about C++ (again) ?

[wysota]

It's not undefined. It is uninitialised (meaning it contains some random value). You probably defined it as a member variable.

[jacek]

yes warn_on is there

Then maybe you initialize it to 0 in constructor or you haven't noticed the warning?

As far as I know even Basic would complain about an undefined variable

AFAIK it would just define that variable itself (at least VB)

[incapacitant]

yes it is defined in the class as private member. Is being a member means be defined and allocated ? If the compiler is able to spot unused variable, why is it not possible to spot uninitialized variables ?

AFAIK means ??

[wysota]

yes it is defined in the class as private member. Is being a member means be defined and allocated ? If the compiler is able to spot unused variable, why is it not possible to spot uninitialized variables ?

Maybe you need to enable some option of the compiler?

AFAIK means ??

"As far as I know"