[英]What is the cause of a segmentation fault error (signal name: SIGSEGV), and how would I find/fix it?
我一直在開發Qt Creator應用程序,最近才遇到運行時錯誤,我不知道如何查找和修復。 該程序一旦啟動就意外完成,而當我運行調試時,它給了我錯誤:
下等停止,因為它從操作系統接收到信號。
信號名稱:SIGSEGV
信號含義:分段故障
現在,我知道此錯誤是由於嘗試訪問無效的內存位置引起的,但是我完全不知道觸發該錯誤的方法。 調試器似乎將我指向特定的代碼行:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QString>
#include "ui_mainwindow.h"
#include "foamdata.h"
#include "domaingeneration.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
int getXDim() const { return ui->xDim->value(); } // THIS is where it points to!!
int getYDim() const { return ui->yDim->value(); }
private slots:
void on_findDir_clicked();
void on_create_clicked();
void on_generateDomain_clicked();
private:
Ui::MainWindow *ui;
DomainGeneration dg; //declaring second window as a member of main window
};
#endif // MAINWINDOW_H
該函數用於:
#include "domaingeneration.h"
#include "ui_domaingeneration.h"
#include <QCheckBox>
#include "mainwindow.h"
DomainGeneration::DomainGeneration(QWidget *parent) :
QDialog(parent),
ui(new Ui::DomainGeneration)
{
ui->setupUi(this);
// Generating checkboxes for domain generation
MainWindow* main;
int x_dim = main->getXDim();
int y_dim = main->getYDim();
QVector<QCheckBox*> checkBoxVector;
for(int i = 0; i < x_dim; ++i){
for(int j = 0; j < y_dim; ++j){
checkBoxVector.append(new QCheckBox(this));
checkBoxVector.last()->setGeometry(i * 20, j * 20, 20, 20);
}
}
}
DomainGeneration::~DomainGeneration()
{
delete ui;
}
這是主窗口源代碼:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "functions.h"
#include "main.cpp"
#include <QtGui/QApplication>
#include <QFileDialog>
#include <fstream>
#include "foamdata.h"
#include "domaingeneration.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
// This is the function that handles the directory search when the 'browse' button is pressed
void MainWindow::on_findDir_clicked()
{
QString path; //declaring the path to the base directory
path = QFileDialog::getExistingDirectory( //gathering the directory from QFileDialog class
this, tr("Choose the project directory"),
"/home",
QFileDialog::ShowDirsOnly
| QFileDialog::DontResolveSymlinks );
ui->baseDir->setText( path ); //setting the retrieved path into the line edit box
}
// This function makes the project by creating a new directory with name 'project_name'
// in the base directory, and collects the OpenFOAM version number and simulation type
void MainWindow::on_create_clicked()
{
QString project_name, foam_version, full_dir, slash, base_dir;
base_dir = ui->baseDir->text();
project_name = ui->projectName->text(); //getting the text from the 'projectName' field
foam_version = ui->version->currentText(); //getting the selection from the 'version' drop-down box
project_info.save_version(foam_version); //saving data in a global project variable
project_info.save_projName(project_name);
project_info.save_simType(ui->simType->currentText());
//first checking if the fields have input in them:
QString blank = "";
QString no_text0 = "Please enter project name";
if( project_name==no_text0 || (project_name==blank) ) {
ui->projectName->setText( no_text0 );
return;
}
QString no_text1 = "Please enter a valid directory";
if( base_dir==no_text1 || base_dir==blank || !QDir( base_dir ).exists() ) {
ui->baseDir->setText( no_text1 );
return;
}
slash = "/"; // needed to separate folders in the directory (can't use a literal)
full_dir = base_dir.append(slash.append(project_name));
project_info.save_directory(full_dir);
if( !QDir(full_dir).exists() ) //check if directory already exists
QDir().mkdir(full_dir); //creating directory
QString blockmesh_filename, suffix;
suffix = "_blockMeshDict";
slash = "/"; //must re-define
blockmesh_filename = full_dir.append( slash.append( project_name.append(suffix) ) );
std::ofstream create_file( blockmesh_filename.toStdString().c_str() ); //creating empty blockmesh file
}
void MainWindow::on_generateDomain_clicked() //opening the new window for domain generation
{
dg.show();
}
誰能幫助我找到到底發生了什么?
很明顯,您沒有初始化MainWindow * main;
:
MainWindow* main; // right here
int x_dim = main->getXDim();
int y_dim = main->getYDim();
但是,可能還有其他未初始化的值,所提供的代碼並沒有說太多。
或在這里:
// Generating checkboxes for domain generation
MainWindow* main;
int x_dim = main->getXDim();
int y_dim = main->getYDim();
main
絕對不會指向任何地方!
您在類MainWindow
中有一個私有數據成員ui
,它為NULL。 永遠不會設置該變量。 實際上,沒有辦法設置它。 (二傳手在哪里?)
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