Segment fault

[kenchan]

Hi All,


use Qt Creator 4.7 , didn't use designer, a dockwidget has several filters, Segment fault when complied,codes as below:

dockWidget = new QDockWidget(this);
dockWidget->setObjectName(QString::fromUtf8("dockWidget"));

dockWidgetContents = new QWidget();
dockWidgetContents->setObjectName(QString::fromUtf8("dockWidgetConten ts"));

gridLayout = new QGridLayout(dockWidgetContents);
gridLayout->setSpacing(6);
gridLayout->setObjectName(QString::fromUtf8("gridLayout"));

horizontalLayout_2 = new QHBoxLayout();//Segment fault
horizontalLayout_2->setSpacing(6);
horizontalLayout_2->setObjectName(QString::fromUtf8("horizontalLayout _2"));

time_dateEdit = new QDateEdit(dockWidgetContents);
time_dateEdit->setObjectName(QString::fromUtf8("time_dateEdit")) ;

horizontalLayout_2->addWidget(time_dateEdit);

horizontalSpacer_2 = new QSpacerItem(18, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);

horizontalLayout_2->addItem(horizontalSpacer_2);

lcdNumber = new QLCDNumber(dockWidgetContents);
lcdNumber->setObjectName(QString::fromUtf8("lcdNumber"));
horizontalLayout_2->addWidget(lcdNumber);


gridLayout->addLayout(horizontalLayout_2, 0, 0, 1, 1);

horizontalLayout = new QHBoxLayout();//segment fault
horizontalLayout->setSpacing(6);
horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout "));
horizontalSlider = new QSlider(dockWidgetContents);
horizontalSlider->setObjectName(QString::fromUtf8("horizontalSlider "));
horizontalSlider->setOrientation(Qt::Horizontal);

horizontalLayout->addWidget(horizontalSlider);

openBtn = new QPushButton(dockWidgetContents);
openBtn->setObjectName(QString::fromUtf8("openfileBtn")) ;

horizontalLayout->addWidget(openfileBtn);

preBtn = new QPushButton(dockWidgetContents);
preBtn->setObjectName(QString::fromUtf8("preBtn"));

horizontalLayout->addWidget(preBtn);

gridLayout->addLayout(horizontalLayout, 1, 0, 1, 1);

dockWidget->setWidget(dockWidgetContents);


Please give me any advice!

TKS.

ken

[amleto]

explain exactly what you have done for all qt installations - what compiler you used.

what compiler are you using now?

What do you do to compile your programs? What is your PATH like?

[kenchan]

if the code changed as below, the layout is didn't i want to layout.
horizontalLayout = new QHBoxLayout(dockWidgetContents);
horizontalLayout = new QHBoxLayout(dockWidgetContents);

and if the code changed as below, segment fault also.
horizontalLayout = new QHBoxLayout(dockWidget );
horizontalLayout = new QHBoxLayout(dockWidget );

Hi amleto,
i use mingw32 to compile my program.

[amleto]

hi, please read my post, above, and answer the questions. Thanks.

also state how you build your application e.g. pro file.

[kenchan]

Hi amleto,
i use mingw32 complier.
complied success if i use designer to build the project which has several filters in dockwidget,
but i want to write codes to build the project to complete what i want, so i consulted ui_mainwindow.h as above.

thanks.

ken

[amleto]

It seems you have some difficulty in understanding my questions? You have not answered all of them.

Qt designer is not even an IDE - it can't even start a compiler so you are not using designer to build your code.

[wysota]

Hi All,


use Qt Creator 4.7 , didn't use designer, a dockwidget has several filters, Segment fault when complied,codes as below:

dockWidget = new QDockWidget(this);
dockWidget->setObjectName(QString::fromUtf8("dockWidget"));

dockWidgetContents = new QWidget();
dockWidgetContents->setObjectName(QString::fromUtf8("dockWidgetConten ts"));

gridLayout = new QGridLayout(dockWidgetContents);
gridLayout->setSpacing(6);
gridLayout->setObjectName(QString::fromUtf8("gridLayout"));

horizontalLayout_2 = new QHBoxLayout();//Segment fault
horizontalLayout_2->setSpacing(6);
horizontalLayout_2->setObjectName(QString::fromUtf8("horizontalLayout _2"));

time_dateEdit = new QDateEdit(dockWidgetContents);
time_dateEdit->setObjectName(QString::fromUtf8("time_dateEdit")) ;

horizontalLayout_2->addWidget(time_dateEdit);

horizontalSpacer_2 = new QSpacerItem(18, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);

horizontalLayout_2->addItem(horizontalSpacer_2);

lcdNumber = new QLCDNumber(dockWidgetContents);
lcdNumber->setObjectName(QString::fromUtf8("lcdNumber"));
horizontalLayout_2->addWidget(lcdNumber);


gridLayout->addLayout(horizontalLayout_2, 0, 0, 1, 1);

horizontalLayout = new QHBoxLayout();//segment fault
horizontalLayout->setSpacing(6);
horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout "));
horizontalSlider = new QSlider(dockWidgetContents);
horizontalSlider->setObjectName(QString::fromUtf8("horizontalSlider "));
horizontalSlider->setOrientation(Qt::Horizontal);

horizontalLayout->addWidget(horizontalSlider);

openBtn = new QPushButton(dockWidgetContents);
openBtn->setObjectName(QString::fromUtf8("openfileBtn")) ;

horizontalLayout->addWidget(openfileBtn);

preBtn = new QPushButton(dockWidgetContents);
preBtn->setObjectName(QString::fromUtf8("preBtn"));

horizontalLayout->addWidget(preBtn);

gridLayout->addLayout(horizontalLayout, 1, 0, 1, 1);

dockWidget->setWidget(dockWidgetContents);


Please give me any advice!

TKS.

ken

So... you got two segmentation faults at once?

[amleto]

I didn't even want to go there!

[kenchan]

Hi wysota,
segment fault when app quit, when i debugged, complier prompted segment fault at "QHBoxLayout".

Hi amleto,

my English is not good, i'm sorry i don't catch all your meaning.

TKS.

ken

[wysota]

If you are getting segmentation faults upon quitting the app, the crash is caused by destructors, not by a constructor. Post the backtrace from your debugger.

[kenchan]

Hi wysota,

Good morning!

thank you for your response.

when i debugged. information reference to segmentation faults as below:

MessageBox:
The inferior stopped because it received a signal from the Operating System.
Signal name:SIGSEGV
Signal meaning:Segmentation fault

debugger:
Stopped:Segmentation fault by signal SIGSEGV

Level Function file line address
0 ~QBoxLayoutItem qboxlayout.cpp 72 0x0112ab69



if i add QWidget to QHBoxLayout(). complied success. see as below:
horizontalLayout_2 = new QHBoxLayout(dockWidgetContents );
horizontalLayout = new QHBoxLayout(dockWidgetContents );

[wysota]

Please post the full backtrace, not only the top frame.

[kenchan]

Hi All,

i have handled it. thank you very much.

ken

[amleto]

What was the solution? If someone googles their own problem and finds this thread, they will be frustrated to see 'solved!', but nobody posted the solution...

[kenchan]

i used QGridLayout instead of QHBoxLayout, so that the problem have solved!