[PyQt] Problem with QFileSystemWatcher

NARCISO, Rui RUI.NARCISO at airbus.com
Mon Dec 13 10:50:05 GMT 2010

Brilliant guys.
This indeed solved my problem:

The only inconvenient is that I have a message printed to the screen:
QFileSystemWatcher: skipping native engine, using only polling engine

That I can't seem to get rid of ...  oh well ...

Cheers and thank you all of your help.


-----Message d'origine-----
De : pyqt-bounces at riverbankcomputing.com [mailto:pyqt-bounces at riverbankcomputing.com] De la part de Baz Walter
Envoyé : vendredi 10 décembre 2010 19:43
À : Hans-Peter Jansen
Cc : pyqt at riverbankcomputing.com
Objet : Re: [PyQt] Problem with QFileSystemWatcher

On 10/12/10 18:10, Hans-Peter Jansen wrote:
> Dear Rui,
> On Friday 10 December 2010, 11:08:50 NARCISO, Rui wrote:
>> When I use absolute paths (os.path.abspath) or real paths
>> (os.path.realpath) or even relative paths (../../toto) it doesn't
>> work. It only works when I use only the file name.
> Works fine here with absolute paths. Consequently, it triggers all four connected signals, if I touch the watched file in my home.
> Guys, if you rely on some special file argument, why can't you provide a global variable or even better, a command line parameter.
>> I don't think permissions are the problem because I tried the with
>> the same file in the current folder and then in the parent folder and
>> it works for the first and it doesn't for the latter...
>> I'm on a Linux workstation accessing hard drives physically stored in
>> a data center elsewhere. Can this be the problem ? I would think not
>> because if it works for a file in the current folder it should work
>> for the parent folder as well since both are in the same hard
>> drive/filer ...
> My home is NFS, too. If I remember correctly, Qt uses simple timer based polling for the file system watcher since being multi-platform they cannot rely on any special OS kernel/filesystem feature.
>> Any insight anyone ?
> Yes, you're using ancient versions of everything. This is most probably,  what does harm in your case.

the problem appears to be the one detailed in this thread:


there is a 'workaround' suggested there, but it is somewhat hackish, and 
may not be available in the version of qt the op is using.

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