My Ubuntu installation config variables:

Linux kubic-roman 2.6.24-22-generic #1 SMP Mon Nov 24 18:32:42 UTC 2008 i686 GNU/Linux

generated by APUE2 book chapter 2 program:

opt.txt

_POSIX_ADVISORY_INFO is defined (val is 200112)
sysconf says _POSIX_ADVISORY_INFO = 200112

_POSIX_ASYNCHRONOUS_IO is defined (val is 200112)
sysconf says _POSIX_ASYNCHRONOUS_IO = 200112

_POSIX_BARRIERS is defined (val is 200112)
sysconf says _POSIX_BARRIERS = 200112

_POSIX_CPUTIME is defined (val is 0)
sysconf says _POSIX_CPUTIME = 200112

_POSIX_CLOCK_SELECTION is defined (val is 200112)
sysconf says _POSIX_CLOCK_SELECTION = 200112

_POSIX_FSYNC is defined (val is 200112)
sysconf says _POSIX_FSYNC = 200112

_POSIX_IPV6 is defined (val is 200112)
sysconf says _POSIX_IPV6 = 200112

_POSIX_MAPPED_FILES is defined (val is 200112)
sysconf says _POSIX_MAPPED_FILES = 200112

_POSIX_MEMLOCK is defined (val is 200112)
sysconf says _POSIX_MEMLOCK = 200112

_POSIX_MEMLOCK_RANGE is defined (val is 200112)
sysconf says _POSIX_MEMLOCK_RANGE = 200112

_POSIX_MONOTONIC_CLOCK is defined (val is 0)
sysconf says _POSIX_MONOTONIC_CLOCK = 200112

_POSIX_MEMORY_PROTECTION is defined (val is 200112)
sysconf says _POSIX_MEMORY_PROTECTION = 200112

_POSIX_MESSAGE_PASSING is defined (val is 200112)
sysconf says _POSIX_MESSAGE_PASSING = 200112

_POSIX_PRIORITIZED_IO is defined (val is 200112)                              
sysconf says _POSIX_PRIORITIZED_IO = 200112

_POSIX_PRIORITIZED_SCHEDULING is undefined
no symbol for _POSIX_PRIORITIZED_SCHEDULING

_POSIX_RAW_SOCKETS is defined (val is 200112)
sysconf says _POSIX_RAW_SOCKETS = 200112

_POSIX_REALTIME_SIGNALS is defined (val is 200112)
sysconf says _POSIX_REALTIME_SIGNALS = 200112

_POSIX_SEMAPHORES is defined (val is 200112)
sysconf says _POSIX_SEMAPHORES = 200112

_POSIX_SHARED_MEMORY_OBJECTS is defined (val is 200112)
sysconf says _POSIX_SHARED_MEMORY_OBJECTS = 200112

_POSIX_SYNCHRONIZED_IO is defined (val is 200112)
sysconf says _POSIX_SYNCHRONIZED_IO = 200112

_POSIX_SPIN_LOCKS is defined (val is 200112)
sysconf says _POSIX_SPIN_LOCKS = 200112

_POSIX_SPAWN is defined (val is 200112)
sysconf says _POSIX_SPAWN = 200112

_POSIX_SPORADIC_SERVER is defined (val is -1)
sysconf says _POSIX_SPORADIC_SERVER = (no limit)

_POSIX_THREAD_CPUTIME is defined (val is 0)
sysconf says _POSIX_THREAD_CPUTIME = 200112

_POSIX_TRACE_EVENT_FILTER is defined (val is -1)
sysconf says _POSIX_TRACE_EVENT_FILTER = (no limit)
                                                                              
_POSIX_TIMEOUTS is defined (val is 200112)
sysconf says _POSIX_TIMEOUTS = 200112

_POSIX_TIMERS is defined (val is 200112)
sysconf says _POSIX_TIMERS = 200112

_POSIX_THREAD_PRIO_INHERIT is defined (val is 200112)
sysconf says _POSIX_THREAD_PRIO_INHERIT = 200112

_POSIX_THREAD_PRIO_PROTECT is defined (val is 200112)
sysconf says _POSIX_THREAD_PRIO_PROTECT = 200112

_POSIX_THREAD_PRIORITY_SCHEDULING is defined (val is 200112)
sysconf says _POSIX_THREAD_PRIORITY_SCHEDULING = 200112

_POSIX_TRACE is defined (val is -1)
sysconf says _POSIX_TRACE = (no limit)

_POSIX_TRACE_INHERIT is defined (val is -1)
sysconf says _POSIX_TRACE_INHERIT = (no limit)

_POSIX_TRACE_LOG is defined (val is -1)
sysconf says _POSIX_TRACE_LOG = (no limit)

_POSIX_THREAD_ATTR_STACKADDR is defined (val is 200112)
sysconf says _POSIX_THREAD_ATTR_STACKADDR = 200112

_POSIX_THREAD_SAFE_FUNCTIONS is defined (val is 200112)
sysconf says _POSIX_THREAD_SAFE_FUNCTIONS = 200112

_POSIX_THREAD_PROCESS_SHARED is defined (val is 200112)
sysconf says _POSIX_THREAD_PROCESS_SHARED = 200112

_POSIX_THREAD_SPORADIC_SERVER is defined (val is -1)
sysconf says _POSIX_THREAD_SPORADIC_SERVER = (no limit)

_POSIX_THREAD_ATTR_STACKSIZE is defined (val is 200112)
sysconf says _POSIX_THREAD_ATTR_STACKSIZE = 200112                            

_POSIX_THREADS is defined (val is 200112)
sysconf says _POSIX_THREADS = 200112

_POSIX_TYPED_MEMORY_OBJECTS is defined (val is -1)
sysconf says _POSIX_TYPED_MEMORY_OBJECTS = (no limit)

_XOPEN_UNIX is defined (val is 1)
sysconf says _XOPEN_UNIX = 1

_XOPEN_STREAMS is undefined
no symbol for _XOPEN_STREAMS

_XOPEN_CRYPT is defined (val is 1)
sysconf says _XOPEN_CRYPT = 1

_XOPEN_LEGACY is defined (val is 1)
sysconf says _XOPEN_LEGACY = 1

_XOPEN_REALTIME is defined (val is 1)
sysconf says _XOPEN_REALTIME = 1

_XOPEN_REALTIME_THREADS is defined (val is 1)
sysconf says _XOPEN_REALTIME_THREADS = 1

_POSIX_JOB_CONTROL is defined (val is 1)
sysconf says _POSIX_JOB_CONTROL = 1

_POSIX_READER_WRITER_LOCKS is defined (val is 200112)
sysconf says _POSIX_READER_WRITER_LOCKS = 200112

_POSIX_REGEXP is defined (val is 1)
sysconf says _POSIX_REGEXP = 1

_POSIX_SAVED_IDS is defined (val is 1)
sysconf says _POSIX_SAVED_IDS = 1

_POSIX_SHELL is defined (val is 1)
sysconf says _POSIX_SHELL = 1

_XOPEN_ENH_I18N is defined (val is 1)                                         
sysconf says _XOPEN_ENH_I18N = 1

_XOPEN_SHM is defined (val is 1)
sysconf says _XOPEN_SHM = 1

_POSIX_VERSION is defined (val is 200112)
sysconf says _POSIX_VERSION = 200112

_XOPEN_VERSION is defined (val is 600)
sysconf says _XOPEN_VERSION = 600

_POSIX_CHOWN_RESTRICTED is defined (val is 1)
pathconf says _POSIX_CHOWN_RESTRICTED = 1

_POSIX_NO_TRUNC is defined (val is 1)
pathconf says _POSIX_NO_TRUNC = 1

_POSIX_VDISABLE is defined (val is 0)
pathconf says _POSIX_VDISABLE = 0

POSIX_ASYNC_IO is undefined
pathconf says POSIX_ASYNC_IO = (no limit)

POSIX_PRIO_IO is undefined
pathconf says POSIX_PRIO_IO = (no limit)

POSIX_SYNC_IO is undefined
pathconf says POSIX_SYNC_IO = (no limit)
----%<----
ARG_MAX defined to be 131072
ARG_MAX = 131072
no symbol for ATEXIT_MAX
ATEXIT_MAX = 2147483647
CHARCLASS_NAME_MAX defined to be 2048
CHARCLASS_NAME_MAX = 2048
no symbol for CHILD_MAX
CHILD_MAX = 8125
no symbol for CLOCKTICKSPERSECOND /*clock ticks/second*/                      
CLOCKTICKSPERSECOND /*clock ticks/second*/ = 100
COLL_WEIGHTS_MAX defined to be 255
COLL_WEIGHTS_MAX = 255
HOST_NAME_MAX defined to be 64
HOST_NAME_MAX = 64
IOV_MAX defined to be 1024
IOV_MAX = 1024
LINE_MAX defined to be 2048
LINE_MAX = 2048
LOGIN_NAME_MAX defined to be 256
LOGIN_NAME_MAX = 256
NGROUPS_MAX defined to be 65536
NGROUPS_MAX = 65536
no symbol for OPEN_MAX
OPEN_MAX = 1024
no symbol for PAGESIZE
PAGESIZE = 4096
no symbol for PAGE_SIZE
PAGE_SIZE = 4096
RE_DUP_MAX defined to be 32767
RE_DUP_MAX = 32767
no symbol for STREAM_MAX
STREAM_MAX = 16
no symbol for SYMLOOP_MAX
SYMLOOP_MAX = (no limit)
TTY_NAME_MAX defined to be 32
TTY_NAME_MAX = 32
no symbol for TZNAME_MAX
TZNAME_MAX = 6
MAX_CANON defined to be 255
MAX_CANON = 255
MAX_INPUT defined to be 255
MAX_INPUT = 255
no symbol for FILESIZEBITS
FILESIZEBITS = 64
no symbol for LINK_MAX
LINK_MAX = 32000
NAME_MAX defined to be 255                                                    
NAME_MAX = 255
PATH_MAX defined to be 4096
PATH_MAX = 4096
PIPE_BUF defined to be 4096
PIPE_BUF = 4096
no symbol for SYMLINK_MAX
SYMLINK_MAX = (no limit)