Question: Sticky bit and socket files in XDG_RUNTIME_DIR

[Miguel Sánchez de León Peque]

Hi,

I am storing some Unix socket files under a sub-directory beneath 
$XDG_RUNTIME_DIR. On the specification, I can read:

 > Files in this directory MAY be subjected to periodic clean-up. To 
ensure that your files are not removed, they should have their access 
time timestamp modified at least once every 6 hours of monotonic time or 
the 'sticky' bit should be set on the file.

I wonder if it is necessary to set the sticky bit on each socket file in 
order to avoid periodic clean-up or if it is sufficient to set the 
sticky bit in the sub-directory in which I am storing all the socket files.

Thanks in advance for your help,

Miguel