The AUTOFLUSH does not solve the problem
The SEEK works !!! and it works without the lock in $sem and the AUTOFLUSH in LOG. However, IMHO the lock in $sem must be used
In overall i've understand your tip, but it's not clear for me how all the file pointers are syncked in a thread concurrency level, without conflicts. With the lock in $sem it's obvious , because only one thread can SEEK the Filehandle and write to it. However, I'm getting the log file syncked without using the lock in $sem. But these are other discussions
Thanks for the tip it will be very useful for me...