[Interest] QNAM::get() spawns three processess and opens file descriptors which I am unable to close

Thiago Macieira thiago.macieira at intel.com
Sat Aug 31 02:35:41 CEST 2013

On quarta-feira, 28 de agosto de 2013 17:11:22, gsmember gs wrote:
> Hi,I wrote a desktop app on Debian5. Right after the first manager->get() I
> opened pstree and htop:root at kvm2:~# pstree | grep votebotserver    
> |-screen---votebotserver---4*[{votebotserver}] htop shows me 4 running
> processess as well.

Those are threads. Don't kill them.

> And after 2 hours, running many
> requests, I hit the user limit of open file descriptors. 

Please show us a small, self-contained, compilable example of the problem. I 
have never heard of file descriptor leakage in Qt.

> "lsof | grep resrv" gave me a bunch of open fd's:[...]
> resrv 12701  root   13r     FIFO                0,8      0t0     319902 pipe
> resrv 12701  root   14w     FIFO                0,8      0t0     319902 pipe

Those are pipes. They aren't related to QNAM, since QNAM doesn't use pipes.

It could be because of the threads. Each thread that you start consumes 2 file 
descriptors in the form of pipes (until Qt 5.1 or until a recent enough glib2 
in your system, then it's only one). But you said that the number of threads 
running was only 3, so that doesn't explain.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
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