On Wed, 21 Nov 2007, Tom St Denis wrote: > forget the j, it's htonl(i) that matters here. It's the only location where there is a implicit cast > from a 64 bits int (i) to a 32 bits int (the parameter of htonl), like the subject is telling you. Use GCC 4.3 and -Wconversion. Read http://gcc.gnu.org/wiki/NewWconversion. If you have any question that is not covered there, add manu@xxxxxxxxxxx to the CC list explicitly, I don't follow gcc-help. Please, notice that I just added the answer to your question to http://gcc.gnu.org/wiki/NewWconversion#faq And don't be sarcastic when you are asking people to spend their time to help you for free, it is rude and makes you look like...well, many things but funny. Cheers, Manuel.