It is. It's a minimum of 512 AFAIK, though on some of my computers it's 8192. It's used for setbuf etc. I like to use it as the amount of memory to increase a string by when I run out (see codeform).
 What's that about a double-linked list? (I think it's "double-linked" and not "doubly-linked" BTW. It's like "fine-toothed comb", which is actually "fine tooth-comb"; there was once a fine type of tooth-comb. ) [/edit]