How to write qreal literals correctly?
How do I write qreal literals, so they do not need to be cast regardless on what CPU architecture I compile?
E.g. I use qMax
qreal someValue = calcFunc();
qreal min = qMin(someValue, 0.0);
The qMin compiles fine on a PC, but throws a compile error on an ARM platform - no qMin exists, which would allow two different types to be compared.
Of course I can write the ugly
qreal min = qMin(someValue, static_cast<qreal>(0.0));
but I feel there must be a better way to write a qreal-literal.
Do you know it?
In basic this has noting to do with qReal values! It is stated in the docs that a qreal is a double on all platforms excluding the ARM achitecture, there it is a float.
For the qMin to work you only need a template capable type, and float is just that.
Do you include the QtGlobal at the top of the file? Maybe the compiler for the PC application runs a bit different then your ARM compiler? That might do the trick.
If you read the code above carefully, you'll see that on a PC, it evaluates to
whereas on ARM it evaluates to
since a literal written like '0.0' is a double.
If I wrote '0.0f', it would work on ARM but not on the PC.
I am looking for something like '0.0q', which makes the literal either float or double - depending on the platform.
Well, maybe a compiler switch should do the trick.
qmin (float, float)
As I wrote above, it does work when using the static_cast<qreal>, it's just ugly.
A compiler switch would be even uglier in my book, unless it's something I could do once and then forget about. But I don't see how I would be able to pull off that trick.