qHash(double) problem with Qt 4.6 (tp1)

[sascha]

Hi,

I am trying to build QWT 5.2 against Qt 4.6 (tp1) with mingw. The compiler complains about ambiguous overloaded qHash, first instatiated in qwt_valuelist.h:48. Event after I change the #ifdef in ine 39 to include a check for QT_VERSION >= 0x040600, the error remains.

Has anybody experienced the same or knows of a solution?

Thanks,
Sascha

[sascha]

I investigated the problem further and it seems to be specific to the combination of MinGW, Qt 4.6 and qwt.

Trying to compile qwt with a native gcc against Qt 4.6 works, as well as compiling qwt with MinGW against Qt 4.5.x.

Any input is highly appreciated.

[Uwe]

Please check Qt 4.6 Beta first. If the problem is still there please try to write a small demo using a QList<double>, that shows the problem without Qwt.

Uwe

[sascha]

Ah, I see that the beta is out since yesterday! I will try it out and post the results.

Thanks,
Sascha

[sascha]

Hi, I compiled the beta now with MinGW (gcc 4.4) and using a QList<double> inside a Qt project without qwt is no problem.

Somehow the compiler gets confused at qwt_valuelist.h:48, where a QList<double> is explicitly instantiated for exporting it in the qwt.dll . Uncommenting this line, results in a successful build of qwt with gcc 4.4 and Qt 4.6 beta1.

Any ideas whats happening there?

Sascha

[Uwe]

Can you compile Qwt 5.2 with Qt 4.5.x and MinGW (gcc 4.4) or is it a problem of the compiler version ?

Uwe

[sascha]

I did that on Linux, cross-compiling with MinGW (gcc 4.4) for Windows and it worked, but I will try it on Windows natively in the next days.

Sascha

[Kazakus]

Had anybody managed with this? I've looked at qhash.h, and it's rewritten since qt 4.5, and I didn't managed to modify qwt so that it compiles for me

[Indalo]

Follow to qwt_valuelist.h and change this:

#if QT_VERSION < 0x040300
// Some compilers have problems, 
// without a qHash(double) implementation
#include <qset.h>
#include <qvector.h>
inline uint qHash(double key) { return uint(key); }
#endif

#if QT_VERSION < 0x040300
// Some compilers have problems, 
// without a qHash(double) implementation
#include <qset.h>
#include <qvector.h>
inline uint qHash(double key) { return uint(key); }
#endif

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to:

#if QT_VERSION == 0x040600
// Some compilers have problems, 
// without a qHash(double) implementation
#include <qset.h>
#include <qvector.h>
inline uint qHash(double key) { return uint(key); }
#endif

#if QT_VERSION == 0x040600
// Some compilers have problems, 
// without a qHash(double) implementation
#include <qset.h>
#include <qvector.h>
inline uint qHash(double key) { return uint(key); }
#endif

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[sascha]

Hi,

the hint posted by Indalo does not work for me.

I am using Qt 4.6 RC now and qwt still doesn't compile without modification. However, changing qwt_valuelist.h:37 from

#if defined(QWT_TEMPLATEDLL)

#if defined(QWT_TEMPLATEDLL)

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to

#if defined(QWT_TEMPLATEDLL) && QT_VERSION < 0x040600

#if defined(QWT_TEMPLATEDLL) && QT_VERSION < 0x040600

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works for me.

[hassenman]

Hi ,

i tried all the tricks mentioned above, none worked !
Any solution ?

Regards,