I'm sending files from our client to the server using TCP. To end the mark of the file, I would like to send the file size before the actual data so I've been using the stat system call. Now I need to know how many actual bytes it occupies so I can read it correctly on the server. It's defined using <sys/types.h> but I can't understand the definition. It just tells me that _off_t or _off64_t is off_t. Can someone point me to where I can find the complete definition of off_t type? Any help would be greatly appreciated.