NOT implemented system interfaces from the Single Unix Specification, Volume 3:
_Exit
acoshl
acosl
aio_cancel
aio_error
aio_fsync
aio_read
aio_return
aio_suspend
aio_write
asinhl
asinl
asnprintf
atan2l
atanhl
atanl
bindresvport
bindresvport_sa
bsd_signal
cabsl
cacos
cacosf
cacosh
cacoshf
cacoshl
cacosl
carg
cargf
cargl
casin
casinf
casinh
casinhf
casinhl
casinl
catan
catanf
catanh
catanhf
catanhl
catanl
cbrtl
ccos
ccosf
ccosh
ccoshf
ccoshl
ccosl
ceill
cexp
cexpf
cexpl
cimag
cimagf
cimagl
clock_getcpuclockid
clog
clogf
clogl
confstr
conj
conjf
conjl
copysignl
coshl
cosl
cpow
cpowf
cpowl
cproj
cprojf
cprojl
creal
crealf
creall
csin
csinf
csinh
csinhf
csinhl
csinl
csqrt
csqrtf
csqrtl
ctan
ctanf
ctanh
ctanhf
ctanhl
ctanl
dn_comp
dn_expand
dn_skipname
dprintf
endnetent
erfcl
erfl
exp10
exp10f
exp2l
expl
expm1l
fabsl
fattach
fdiml
feclearexcept
fegetenv
fegetexceptflag
fegetround
feholdexcept
feraiseexcept
fesetenv
fesetexceptflag
fesetround
fetestexcept
feupdateenv
fgetwc
fgetws
floorl
fmal
fmaxl
fminl
fmodl
fmtmsg
fopencookie
fputwc
fputws
freeaddrinfo
freeifaddrs
frexpl
funopen
fwide
fwprintf
fwscanf
gai_strerror
getaddrinfo
getcontext
getdate
getdate_err
gethostent
getifaddrs
getmsg
getnameinfo
getnetbyaddr
getnetbyname
getnetent
getpmsg
getwc
getwchar
hypotl
if_freenameindex
if_indextoname
if_nameindex
if_nametoindex
ilogbl
initstate
insque
iruserok_sa
isastream
ldexpl
lgammal
lio_listio
llrint
llrintf
llrintl
llround
llroundf
llroundl
lockf
log10l
log1pl
log2l
logbl
logl
lrintl
lroundl
makecontext
mlockall
modfl
mq_close
mq_getattr
mq_notify
mq_open
mq_receive
mq_send
mq_setattr
mq_timedreceive
mq_timedsend
mq_unlink
munlockall
nanl
nearbyintl
nextafterl
nexttowardl
posix_fadvise
posix_fallocate
posix_madvise
posix_mem_offset
posix_memalign
posix_openpt
posix_spawn[...]
posix_trace[...]
posix_typed_[...]
pow10
pow10f
powl
pthread_attr_getguardsize
pthread_attr_getstack
pthread_attr_getstackaddr
pthread_attr_setguardsize
pthread_attr_setstack
pthread_attr_setstackaddr
pthread_barrier[...]
pthread_condattr_getclock
pthread_condattr_setclock
pthread_getcpuclockid
pthread_mutex_timedlock
pthread_rwlock_timedrdlock
pthread_rwlock_timedwrlock
pthread_setschedprio
pthread_spin_[...]
putmsg
rcmd_af
reminderl
remque
remquol
rintl
roundl
rresvport_af
scalblnl
scalbnl
sem_unlink
setcontext
setnetent
shm_open
shm_unlink
sigaltstack
sigtimedwait
sinhl
sinl
sockatmark
sqrtl
stpcpy
stpncpy
strcasestr
strfmon
strtold
swabcontext
swprintf
swscanf
tanhl
tanl
tcgetsid
tgammal
timer_getoverrun
truncl
ulimit
vasnprintf
vdprintf
vfwprintf
vfwscanf
vswprintf
vswscanf
vwprintf
vwscanf
waitid
wcsftime
wcstod
wcstof
wcstoimax
wcstok
wcstol
wcstold
wcstoll
wcstoul
wcstoull
wcstoumax
wcswcs
wcsxfrm
wordexp
wordfree
wscanf