Return/emit/catch

Peter Viola

//1
class Foo : public QObject
{
    Q_OBJECT
public:
    explicit Foo(QObject *parent = 0) :
        m_foo(1)
    {}
    ~Foo()
    {}

private:
    int m_foo;

public slots:
    int divideByBar(int bar = 0)
    {
        if(bar == 0)
            return -1;
        return m_foo / bar;
    }
};


//"mainwindow.h"
#include "foo.h"

class MainWindow
{
    Q_OBJECT
public:
    MainWindow(...)
    {
        Foo *foo = new Foo(this);
        int baz = foo->divideByBar();
        if(baz == -1)
            return;
        qDebug() << "---continue---";
    }
    ~Mainwindow()
    {}
};












//2
class Foo : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int foo READ foo WRITE setFoo NOTIFY fooChanged)
public:
    explicit Foo(QObject *parent = 0) :
        m_foo(1)
    {
        connect(this, SIGNAL(fooChanged(int)), this, SLOT(setFoo(int)));
    }
    ~Foo()
    {}

    int foo() const;

private:
    int m_foo;

signals:
    void fooChanged(int foo);

public slots:
    void setFoo(int foo)
    {
        setProperty("foo", foo);
    }

    int divideByBar(int bar = 0)
    {
        if(bar == 0)
            return -1;
        return m_foo / bar;
    }
};

//"mainwindow.h"
#include "foo.h"

class MainWindow
{
    Q_OBJECT
public:
    MainWindow(...)
    {
        Foo *foo = new Foo(this);
        foo->setFoo(1);
        // | foo->setProperty("foo", 1); ?
        int baz = foo->divideByBar();
        if(baz == -1)
            return;
        qDebug() << "---continue---";
    }
    ~Mainwindow()
    {}
};












//3
class Foo : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int foo READ foo WRITE setFoo NOTIFY fooChanged)
public:
    explicit Foo(QObject *parent = 0) :
        m_foo(0)
    {}
    ~Foo()
    {}

    int foo() const;

private:
    int m_foo;

signals:
    void fooChanged(int foo);
    void bazCreated(int bar);

public slots:
    void setFoo(const int &foo)
    {
        if(foo == m_foo)
            return;
        m_foo = foo;
        emit fooChanged(m_foo);
    }

    void divideByBar(int bar = 0)
    {
        if(bar == 0)
        {
            //emit?
            emit bazCreated(-1);
            return;
        }
        //emit?
        emit bazCreated(m_foo / bar);
    }
};

//"mainwindow.h"
#include "foo.h"

class MainWindow
{
    Q_OBJECT
public:
    MainWindow(...)
    {
        Foo *foo = new Foo(this);
        connect(foo, SIGNAL(bazCreated(int)), this, SLOT(bazCreated(int)));
        foo->divideByBar();
    }
    ~Mainwindow()
    {}

public slots:
    void bazCreated(int baz)
    {
        if(baz == -1)
            return;

        "---continue---";
    }
};












//4
class Foo : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int foo MEMBER m_foo NOTIFY fooChanged)
public:
    explicit Foo(QObject *parent = 0) :
        m_foo(0)
    {}
    ~Foo()
    {}

    int foo() const;

private:
    int m_foo;

public slots:
    double divideByBar(int bar = 0)
    {
        double baz = -1;
        if(bar == 0)
            throw baz;
        baz = m_foo / bar;
        return baz;
    }
};

//"mainwindow.h"
#include "foo.h"

class MainWindow
{
    Q_OBJECT
public:
    MainWindow(...)
    {
        Foo *foo = new Foo(this);
        try
        {
            foo->divideByBar();
        }
        catch(int baz)
        {
            "---continue---";
        }
    }
    ~Mainwindow()
    {}
};

SGaist

Hi and welcome to devnet,

What would your question exactly be ?