Inversed result when testing QFileSystemModel::permissions() with flag QFile::WriteUser

using QFileSystemModel, I wrote this to test permissions of some files :

QFileSystemModel* fsModel = new QFileSystemModel (this);

[...]

bool isWritable = fsModel->permissions (index).testFlag (QFile::WriteUser);

I noticed that isWritable == true when a file is read only (all files in /usr, /boot...)
and isWritable == false when user can write into ($HOME/*)
so flag is "inversed"

I got no such problem using QFileInfo::permissions () : result is OK.

a French discussion here -> http://www.qtfr.org/viewtopic.php?pid=79229#p79229

forum member BBenj said that he found same issue with Qt for Mac OS

Thank for your answer

PPJ aka Gilles