I suppose you are familiar with C and especially ANSI C - if not you should read a good book about it 1. This chapter only contains some special features of the implementation - you should know these if you want to use this library.
 I recommend this one:
Brian W. Kernighan, Dennis M.Ritchie:
The C Programming Language (Second Edition)
Prentice Hall, Englewood Cliffs, 1988