QWTPolar & Windows issues

[aetoni]

Hi all,

I successfully built-up Linux version of QT application, but I simply can not run application when build on
Windows platform.

I always get error:

The application was unable to start correctly (0xc0000005). Click OK
to close the application.

Application includes QWT and QWTPolar and I also built-up examples, which comes together. The QWT examples
are running OK, but QWTPolar examples are reporting the same error like my application.

I am using QT 4.8.1, mingw (gcc 4.4.0), QWT 6.0.1 and QWTPolar 1.0.0.

When building QWTPolar I always get an error during build if I downloaded sources in zip file. If I get it from SVN
the QWTPolar built-up OK, except of some warnings like:

compiling plot.cpp
In file included from ..\..\..\Qwt-6.0.1\include/qwt_raster_data.h:14,
from plot.cpp:5:
..\..\..\Qwt-6.0.1\include/qwt_interval.h:270: warning: 'bool QwtInterval::isVal
id() const' redeclared without dllimport attribute after being referenced with dll linkage

and

c:/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: warning: auto-importing
has been activated without --enable-auto-import specified on the command line.
This should work unless it involves constant data structures referencing symbols
from auto-imported DLLs.

Thanks and best regards

[d_stranz]

You should be posting Qwt related questions in the Qwt sub-forum here.

0xc0000005

This error occurs because you are trying to use a null, uninitialized, or otherwise bad pointer. It is due to an error in your code somewhere.

compiling plot.cpp
In file included from ..\..\..\Qwt-6.0.1\include/qwt_raster_data.h:14,
from plot.cpp:5:
..\..\..\Qwt-6.0.1\include/qwt_interval.h:270: warning: 'bool QwtInterval::isValid() const' redeclared without dllimport attribute after being referenced with dll linkage

This is a known warning, and the solution was recently found and posted to the Qwt mailing list. It has to do with isValid() being used in a method before it has been defined inline, because the compiler has already created a non-inline reference to the method. It will be fixed in a future release of Qwt but can be safely ignored for now. The fix is basically to rearrange the order that the methods are declared so that isValid() is defined before it is used.