For example, in less than an hour I downloaded a 226KB gzipped tar file, expanded it, ran Stevens' configuration routine, ran the Makefile which builds the library used by all programs and subsequent Makefiles, and compiled the programs for Chapter 1. During the make of the library, I had a small problem because I don't have a threads library on my system. I've not compiled all the programs supplied, but the ones I have compile and run the way the book says they should. Some of these are running IPv4 protocol stacks, others are running IPv6. One of the themes running through the book is how a programmer can write library routines which are protocol stack and system independent.
Real world means the code deals with errors.
Stevens worries about this, and the beginner will benefit from his examples. Annotated means that when code is discussed in the book, the printed listing includes the subdirectory and file name for the code, the lines in the listing are numbered, and the discussion in the text puts an appropriate, line-number range in the margin of the text. The book contains much more than code. Stevens writes well. He has developed a style which allows him to interrupt his narrative discussion with historical and current observations.