The programs in the book are based on the combined UNIX standard (POSIX) as published by the IEEE in 2001 . The POSIX standard consists of a base specification containing mandatory requirements and several optional extensions. Implementations that comply with this standard have the symbol
_POSIX_VERSION defined in
unistd.h as 200112L.
At the time this book was written, none of our test systems claimed to be fully compliant with even the base of this version of this POSIX standard. Table 1.3 on page 19 shows the POSIX extensions that seem to be supported by our test systems. That is, the documentation agrees with the POSIX standard and the programs from the book behave correctly. Until these systems claim compliance, ...