new type in template function

qwe3

Hi,

I have 2 structures:

class MainWindow : public QMainWindow
{
	Q_OBJECT
public:
    typedef struct
    {
        wchar_t a[256];
        wchar_t b[256];
        wchar_t c[256];
    } ABC;

    typedef struct
    {
        wchar_t a[256];
        wchar_t d[512];
    } AD;

............
}

Q_DECLARE_METATYPE(MainWindow::ABC);
Q_DECLARE_METATYPE(MainWindow::AD);

I create two QVectors:

QVector<MainWindow::ABC> vectorAbc;
QVector<MainWindow::AD> vectorAd;

and add some data to this vectors.

Next I register types:

int idABC = qRegisterMetaType<MainWindow::ABC>("ABC");
int idAD = qRegisterMetaType<MainWindow::AD>("AD");

And now I would like to send them to function, so I create:

template <class type>
void MainWindow::updateVector(QVector<type> vector)
{

}

In this function (updateVector) I want do something like:

template <class type>
void MainWindow::updateVector(QVector<type> vector)
{
	if(type == "ABC" )    // of course I don't have to compare type with text; I can compare type with idABC
	{
		for(int i=0; i<vector.size();i++)
        	{
        	        vector[i].A = someValue; 
            		vector[i].B = someValue; 
            		vector[i].C = someValue; 
		}
        }
	else
	{
		for(int i=0; i<vector.size();i++)
        	{
		        vector[i].A = someValue; 
        		vector[i].D = someValue; 
		}
	}
}

[Moved to C++ Gurus ~kshegunov]

sierdzio

What is your question?

kshegunov

if constexpr (std::is_same<type, MainWindow::ABC>::value)  {
   ...
}
else  {
   ...
}

Or alternatively SFINAE out the type and provide two separate overloads:

template <class type>
typename std::enable_if<std::is_same<type, MainWindow::ABC>::value>::type MainWindow::updateVector(QVector<type> vector)
{
}

template <class type>
typename std::enable_if<std::is_same<type, MainWindow::AD>::value>::type MainWindow::updateVector(QVector<type> vector)
{
}

qwe3

How to do this?

Of course I can't compare type with "ABC". This is only pseudocode, which doesn't work.

qwe3

@kshegunov Perfect!