Well it works ... it finds plugins in application directory as described in QCoreApplication::addLibraryPath. It is workaround, but It does not work if all plugin is copied to plugins directory and proper path is set.
To be precise.
App is testapp.exe and is in
C:\Tmp\testapp.exe
iconengine plugin is in
C:\Tmp\plugins\iconengines\qsvg4.dll

and QCoreApplication::addLibraryPath is added as mentioned in my previous message. Just after instanating QApplication.

<code>
QApplication app(argc, argv);
QCoreApplication::addLibraryPath(QCoreApplication: :applicationDirPath()+QString("/plugins"));
</code>


So I am asking what went wrong?