how to provide a global qHash() for QSet

0odiuo0

I would like to create a QSet to contain unassignable value.
Thus, I must provide operator==(), and a global qHash() function.But there is something wrong with my qHash().

here is my code:

entity.h

struct CVexOnSec
{
	CVexOnSec(QVector3D P){ pos = P; }

	QVector3D pos;

	bool operator == (const CVexOnSec &vex) const
	{
		return (pos == vex.pos);
	}
};

entity.cpp

inline uint qHash(const CVexOnSec &t, uint seed)
{
	return qHash(t.pos.x());
}

and the error is error C2665.
located in the code in qhash.h:

template<typename T> inline uint qHash(const T &t, uint seed)
    Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))
{ return (qHash(t) ^ seed); }

what's wrong with my qHash() , and how can I implement it correctly?

VRonin

did you #include <QHash> in entity.cpp? also, I'd declare uint qHash(const CVexOnSec &t, uint seed) in entity.h

mrjj

Hi
in the sample
http://doc.qt.io/qt-5/qhash.html#qhash

it uses 2 parameters for the global qHash
return qHash(key.name(), seed)

and
template<typename T> inline uint qHash(const T &t, uint seed)
seem to want 2.

So my guess u need a seed :)

VRonin

to clarify @mrjj solution, which is 100% right

inline uint qHash(const CVexOnSec &t, uint seed)
{
    return qHash(t.pos.x());
}

should become

inline uint qHash(const CVexOnSec &t, uint seed)
{
    return qHash(t.pos.x(),seed);
}