Dear All, This is the output of uname -a on my RedHat 7.2 machine. Linux yokogawa.npi.stpn.soft.net 2.4.18 #4 SMP Wed Sep 11 12:16:46 IST 2002 i686 unknown In my sources directory usr/src, This is the header of linux-2.4.7-10/net/socket.c file /* NET An implementation of the SOCKET network access protocol. * * Version: @(#)socket.c 1.1.93 18/02/95 My problem is regarding the thread-safeness of sendto () system call. In the above-mentioned socket.c file, these lines are in the header * Alan Cox : Added thread locking to sys_* calls * for sockets. May have errors at the * moment. I am planning to use a single socket for sending ICMP requests through multiple threads.In view of this comment in the socket.c file, should I assume that thread-safety may be buggy with regards to the sendto () call and provide my own user level mutexes around every sendto () call. Your timely suggestion would be a great help to me. With Regards, Atul akumar@networkprograms.com - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html