QT信号槽总结-connect函数错误用法

QT库的qobject.h
connect函数声明：connect函数用于建立信号与槽之间的连接，QT库提供了三种实现：

    static QMetaObject::Connection connect(const QObject *sender, const char *signal,
                        const QObject *receiver, const char *member, Qt::ConnectionType = Qt::AutoConnection);

static QMetaObject::Connection connect(const QObject *sender, const QMetaMethod &signal,
                    const QObject *receiver, const QMetaMethod &method,
                    Qt::ConnectionType type = Qt::AutoConnection);

    inline QMetaObject::Connection connect(const QObject *sender, const char *signal,
                        const char *member, Qt::ConnectionType type = Qt::AutoConnection) const;

class ConnectCamera : public QWidget
{
	Q_OBJECT

public:
	ConnectCamera(QWidget *parent = Q_NULLPTR);
	~ConnectCamera();
	
public slots:
	void onConnectBtnSolt();
	void onCancelBtSolt();
	void onErrorMess(const QString & _errorMess);
signals:
	void signalConnectCamera(const QString& _ip, const QString& _user, const QString& _pass);
private:
	Ui::ConnectCamera ui;
};

使用QT库提供的第一种实现方式，来绑定信号与槽
正确用法1：

connect(ui.okButton, SIGNAL(clicked()), this, SLOT(onConnectBtnSolt()));
connect(ui.cancelButton, SIGNAL(clicked()), this, SLOT(onCancelBtSolt()));

错误用法1：

connect(ui.okButton, SIGNAL(clicked()), this, SLOT(onConnectBtnSolt));

原因分析：
用法1调用的connect函数实际为：

static QMetaObject::Connection connect(const QObject *sender, const char *signal,
                        const QObject *receiver, const char *member, Qt::ConnectionType = Qt::AutoConnection);
                        
// SLOT的定义
Q_CORE_EXPORT const char *qFlagLocation(const char *method);
# define SLOT(a)     qFlagLocation("1"#a QLOCATION)

qt中的信号槽，实际用的是回调函数，onConnectBtnSolt（）被解析为函数，onConnectBtnSolt格式判断会出错
网上很详细的讲解，QT版本可能早于5.9.6
QT QObject：：connect函数的学习