Re: Gio::FileMonitor::signal_changed()

[Kjell Ahlstedt <kjellahlstedt gmail com>]

I get the same results in Ubuntu 17.10. other_file is nullptr if a file 
is moved into or out of the monitored directory. I don't know how to 
interpret "if supported by the backend". Perhaps the backend in our case 
doesn't give any information about what happens outside the monitored 
directory. This is something you should ask on a gtk+ list, probably 
gtk-app-devel-list. The documentation of signal_changed(), like most 
documentation of glibmm classes,  is copied from glib, and slightly 
modified for C++.

Kjell

On 2017-11-18 22:17, Phil Wolff wrote:
> From the Gio::FileMonitor::signal_changed() documentation:
>
> "If using FILE_MONITOR_WATCH_MOVES on a directory monitor, and the 
> information is available (and if supported by the backend), event_type 
> may be FILE_MONITOR_EVENT_RENAMED, FILE_MONITOR_EVENT_MOVED_IN or 
> FILE_MONITOR_EVENT_MOVED_OUT."
>
> I'm using Ubuntu 17.04 (glibmm-2.4 version 2.50.0) on an EXT4 file 
> system, and I obtain the FileMonitor using the 
> FILE_MONITOR_WATCH_MOVES flag. My callback receives all three of these 
> event types, so presumably the information *is* available and supported.
>
> More from the docs:
>
> "In all cases file will be a child of the monitored directory. For 
> renames, file will be the old name and other_file is the new name. For 
> 'moved in' events, file is the name of the file that appeared and 
> other_file is the old name that it was moved from (in another 
> directory). For 'moved out' events, file is the name of the file that 
> used to be in this directory and other_file is the name of the file at 
> its new location."
>
> My callback gets a non-null other_file *only* on a rename; other_file 
> is always null for either of the "moved" events. That's not the 
> behavior described above, but it does match what the docs say about 
> the deprecated Gio::FILE_MONITOR_SEND_MOVED flag (which I am *not* 
> using):
>
> "If using the deprecated flag FILE_MONITOR_SEND_MOVED flag and 
> event_type is FILE_MONITOR_EVENT_MOVED, file will be set to a File 
> containing the old path, and other_file will be set to a File 
> containing the new path.
>
> "In all the other cases, other_file will be set to #nullptr."
>
> There's obviously a problem here, but it's not clear to me where it lies.