Note that the core of the Single Unix Specification, Version 4 is also IEEE Std 1003.1-2008 (POSIX.1-2008). FD_CLR FD_ISSET FD_SET FD_ZERO _Exit _exit _longjmp _setjmp _tolower _toupper a64l abort abs accept access acos acosf acosh acoshf acoshl acosl alarm alphasort asctime asctime_r asin asinf asinh asinhf asinhl asinl atan atan2 atan2f atan2l atanf atanh atanhf atanhl atanl atexit atof atoff atoi atol atoll basename (see chapter "Implementation Notes") bind bsearch btowc cabs cabsf cabsl cacos cacosf cacosh cacoshf cacoshl cacosl calloc carg cargf cargl casin casinf casinh casinhf casinhl casinl catan catanf catanh catanhf catanhl catanl catclose (available in external "catgets" library) catgets (available in external "catgets" library) catopen (available in external "catgets" library) cbrt cbrtf cbrtl ccos ccosf ccosh ccoshf ccoshl ccosl ceil ceilf ceill cexp cexpf cexpl cfgetispeed cfgetospeed cfsetispeed cfsetospeed chdir chmod chown cimag cimagf cimagl clearerr clock clock_getcpuclockid clock_getres clock_gettime clock_nanosleep (see chapter "Implementation Notes") clock_settime (see chapter "Implementation Notes") clog clogf clogl close closedir closelog confstr conj conjf conjl connect copysign copysignf copysignl cos cosf cosh coshf coshl cosl cpow cpowf cpowl cproj cprojf cprojl creal crealf creall creat crypt (available in external "crypt" library) csin csinf csinh csinhf csinhl csinl csqrt csqrtf csqrtl ctan ctanf ctanh ctanhf ctanhl ctanl ctermid ctime ctime_r daylight dbm_clearerr (available in external "libgdbm" library) dbm_close (available in external "libgdbm" library) dbm_delete (available in external "libgdbm" library) dbm_error (available in external "libgdbm" library) dbm_fetch (available in external "libgdbm" library) dbm_firstkey (available in external "libgdbm" library) dbm_nextkey (available in external "libgdbm" library) dbm_open (available in external "libgdbm" library) dbm_store (available in external "libgdbm" library) difftime dirfd dirname div dlclose dlerror dlopen dlsym dprintf drand48 dup dup2 duplocale encrypt (available in external "crypt" library) endgrent endhostent endprotoent endpwent endservent endutxent environ erand48 erf erfc erfcf erfcl erff erfl errno execl execle execlp execv execve execvp exit exp exp2 exp2f exp2l expf expl expm1 expm1f expm1l fabs fabsf fabsl faccessat fchdir fchmod fchmodat fchown fchownat fclose fcntl (see chapter "Implementation Notes") fdatasync fdim fdimf fdiml fdopen fdopendir feclearexcept fegetenv fegetexceptflag fegetround feholdexcept feof feraiseexcept ferror fesetenv fesetexceptflag fesetround fetestexcept feupdateenv fexecve fflush ffs fgetc fgetpos fgets fgetwc fgetws fileno flockfile floor floorf floorl fma fmaf fmal fmax fmaxf fmaxl fmemopen fmin fminf fminl fmod fmodf fmodl fnmatch fopen fork fpathconf fpclassify (see chapter "Implementation Notes") fprintf fputc fputs fputwc fputws fread free freeaddrinfo freelocale freopen frexp frexpf frexpl fscanf fseek fseeko fsetpos fstat fstatat fstatvfs fsync ftell ftello ftok ftruncate ftrylockfile ftw funlockfile futimens fwide fwprintf fwrite fwscanf gai_strerror getaddrinfo getc getc_unlocked getchar getchar_unlocked getcwd getdelim getdomainname getegid getenv geteuid getgid getgrent getgrgid getgrgid_r getgrnam getgrnam_r getgroups gethostid gethostname getitimer (see chapter "Implementation Notes") getline getlogin getlogin_r getnameinfo getopt getpeername getpgid getpgrp getpid getppid getpriority getprotobyname getprotobynumber getprotoent getpwent getpwnam getpwnam_r getpwuid getpwuid_r getrlimit getrusage gets getservbyname getservbyport getservent getsid getsockname getsockopt getsubopt gettimeofday getuid getutxent getutxid getutxline getwc getwchar glob globfree gmtime gmtime_r grantpt hcreate hdestroy hsearch htonl htons hypot hypotf hypotl iconv (available in external "libiconv" library) iconv_close (available in external "libiconv" library) iconv_open (available in external "libiconv" library) if_freenameindex if_indextoname if_nameindex if_nametoindex ilogb ilogbf ilogbl imaxabs imaxdiv inet_addr inet_ntoa inet_ntop inet_pton initstate insque ioctl isalnum isalnum_l isalpha isalpha_l isascii isatty isblank isblank_l iscntrl iscntrl_l isdigit isdigit_l isfinite (see chapter "Implementation Notes") isgraph isgraph_l isgreater (see chapter "Implementation Notes") isgreaterequal (see chapter "Implementation Notes") isinf (see chapter "Implementation Notes") isless islessequal (see chapter "Implementation Notes") islessgreater (see chapter "Implementation Notes") islower islower_l isnan (see chapter "Implementation Notes") isnormal (see chapter "Implementation Notes") isprint isprint_l ispunct ispunct_l isspace isspace_l isunordered (see chapter "Implementation Notes") isupper isupper_l iswalnum iswalnum_l iswalpha iswalpha_l iswblank iswblank_l iswcntrl iswcntrl_l iswctype iswctype_l iswdigit iswdigit_l iswgraph iswgraph_l iswlower iswlower_l iswprint iswprint_l iswpunct iswpunct_l iswspace iswspace_l iswupper iswupper_l iswxdigit iswxdigit_l isxdigit isxdigit_l j0 j1 jn jrand48 kill killpg l64a labs lchown lcong48 ldexp ldexpf ldexpl ldiv lfind lgamma lgammaf lgammal link linkat listen llabs lldiv llrint llrintf llrintl llround llroundf llroundl localeconv localtime localtime_r lockf (see chapter "Implementation Notes") log log10 log10f log10l log1p log1pf log1pl log2 log2f log2l logb logbf logbl logf logl longjmp lrand48 lrint lrintf lrintl lround lroundf lroundl lsearch lseek lstat malloc mblen mbrlen mbrtowc mbsinit mbsnrtowcs mbsrtowcs mbstowcs mbtowc memccpy memchr memcmp memcpy memmove memset mkdir mkdirat mkdtemp mkfifo mkfifoat mknod mknodat mkstemp mktime mlock mmap modf modff modfl mprotect mq_close mq_getattr mq_notify mq_open mq_receive mq_send mq_setattr mq_timedreceive mq_timedsend mq_unlink mrand48 msgctl (see chapter "Implementation Notes") msgget (see chapter "Implementation Notes") msgrcv (see chapter "Implementation Notes") msgsnd (see chapter "Implementation Notes") msync munlock munmap nan nanf nanl nanosleep nearbyint nearbyintf nearbyintl newlocale nextafter nextafterf nextafterl nexttoward nexttowardf nexttowardl nftw nice nl_langinfo nl_langinfo_l nrand48 ntohl ntohs open open_memstream open_wmemstream openat opendir openlog optarg opterr optind optopt pathconf pause pclose perror pipe poll popen posix_fadvise posix_fallocate posix_madvise posix_memalign posix_openpt posix_spawn posix_spawn_file_actions_addclose posix_spawn_file_actions_adddup2 posix_spawn_file_actions_addopen posix_spawn_file_actions_destroy posix_spawn_file_actions_init posix_spawnattr_destroy posix_spawnattr_getflags posix_spawnattr_getpgroup posix_spawnattr_getschedparam posix_spawnattr_getschedpolicy posix_spawnattr_getsigdefault posix_spawnattr_getsigmask posix_spawnattr_init posix_spawnattr_setflags posix_spawnattr_setpgroup posix_spawnattr_setschedparam posix_spawnattr_setschedpolicy posix_spawnattr_setsigdefault posix_spawnattr_setsigmask posix_spawnp pow powf powl pread printf pselect psiginfo psignal pthread_atfork pthread_attr_destroy pthread_attr_getdetachstate pthread_attr_getguardsize pthread_attr_getinheritsched pthread_attr_getschedparam pthread_attr_getschedpolicy pthread_attr_getscope pthread_attr_getstack pthread_attr_getstacksize pthread_attr_init pthread_attr_setdetachstate pthread_attr_setguardsize pthread_attr_setinheritsched pthread_attr_setschedparam pthread_attr_setschedpolicy pthread_attr_setscope pthread_attr_setstack pthread_attr_setstacksize pthread_barrier_destroy pthread_barrier_init pthread_barrier_wait pthread_barrierattr_destroy pthread_barrierattr_getpshared pthread_barrierattr_init pthread_barrierattr_setpshared pthread_cancel pthread_cond_broadcast pthread_cond_destroy pthread_cond_init pthread_cond_signal pthread_cond_timedwait pthread_cond_wait pthread_condattr_destroy pthread_condattr_getclock pthread_condattr_getpshared pthread_condattr_init pthread_condattr_setclock pthread_condattr_setpshared pthread_create pthread_detach pthread_equal pthread_exit pthread_getconcurrency pthread_getcpuclockid pthread_getschedparam pthread_getspecific pthread_join pthread_key_create pthread_key_delete pthread_kill pthread_mutex_destroy pthread_mutex_getprioceiling pthread_mutex_init pthread_mutex_lock pthread_mutex_setprioceiling pthread_mutex_timedlock pthread_mutex_trylock pthread_mutex_unlock pthread_mutexattr_destroy pthread_mutexattr_getprioceiling pthread_mutexattr_getprotocol pthread_mutexattr_getpshared pthread_mutexattr_gettype pthread_mutexattr_init pthread_mutexattr_setprioceiling pthread_mutexattr_setprotocol pthread_mutexattr_setpshared pthread_mutexattr_settype pthread_once pthread_rwlock_destroy pthread_rwlock_init pthread_rwlock_rdlock pthread_rwlock_timedrdlock pthread_rwlock_timedwrlock pthread_rwlock_tryrdlock pthread_rwlock_trywrlock pthread_rwlock_unlock pthread_rwlock_wrlock pthread_rwlockattr_destroy pthread_rwlockattr_getpshared pthread_rwlockattr_init pthread_rwlockattr_setpshared pthread_self pthread_setcancelstate pthread_setcanceltype pthread_setconcurrency pthread_setschedparam pthread_setschedprio pthread_setspecific pthread_sigmask pthread_spin_destroy pthread_spin_init pthread_spin_lock pthread_spin_trylock pthread_spin_unlock pthread_testcancel ptsname putc putc_unlocked putchar putchar_unlocked putenv puts pututxline putwc putwchar pwrite qsort raise rand rand_r random read readdir readdir_r readlink readlinkat readv realloc realpath recv recvfrom recvmsg regcomp regerror regexec regfree remainder remainderf reminderl remove remque remquo remquof remquol rename renameat rewind rewinddir rint rintf rintl rmdir round roundf roundl scalbln scalblnf scalblnl scalbn scalbnf scalbnl scandir scanf sched_get_priority_max sched_get_priority_min sched_getparam sched_getscheduler sched_rr_get_interval sched_setparam sched_setscheduler sched_yield seed48 seekdir select sem_close sem_destroy sem_getvalue sem_init sem_open sem_post sem_timedwait sem_trywait sem_unlink sem_wait semctl (see chapter "Implementation Notes") semget (see chapter "Implementation Notes") semop (see chapter "Implementation Notes") send sendmsg sendto setbuf setegid setenv seteuid setgid setgrent sethostent setitimer (see chapter "Implementation Notes") setjmp setkey (available in external "crypt" library) setlocale setlogmask setpgid setpgrp setpriority setprotoent setpwent setregid setreuid setrlimit setservent setsid setsockopt setstate setuid setutxent setvbuf shm_open shm_unlink shmat (see chapter "Implementation Notes") shmctl (see chapter "Implementation Notes") shmdt (see chapter "Implementation Notes") shmget (see chapter "Implementation Notes") shutdown sigaction sigaddset sigaltstack sigdelset sigemptyset sigfillset sighold sigignore siginterrupt sigismember siglongjmp signal signbit (see chapter "Implementation Notes") signgam sigpause (see chapter "Implementation Notes") sigpending sigprocmask sigqueue sigrelse sigset sigsetjmp sigsuspend sigtimedwait sigwait sigwaitinfo sin sinf sinh sinhf sinhl sinl sleep snprintf sockatmark socket socketpair sprintf sqrt sqrtf sqrtl srand srand48 srandom sscanf stat statvfs stderr stdin stdout stpcpy stpncpy strcasecmp strcasecmp_l strcat strchr strcmp strcoll strcoll_l strcpy strcspn strdup strerror strerror_l strerror_r (see chapter "Implementation Notes") strfmon strfmon_l strftime strftime_l strlen strncasecmp strncasecmp_l strncat strncmp strncpy strndup strnlen strpbrk strptime strrchr strsignal strspn strstr strtod strtof strtoimax strtok strtok_r strtol strtold strtoll strtoul strtoull strtoumax strxfrm strxfrm_l swab swprintf swscanf symlink symlinkat sync sysconf syslog system tan tanf tanh tanhf tanhl tanl tcdrain tcflow tcflush tcgetattr tcgetpgrp tcgetsid tcsendbreak tcsetattr tcsetpgrp tdelete telldir tempnam tfind tgamma tgammaf tgammal time timer_create (see chapter "Implementation Notes") timer_delete timer_gettime timer_settime times timezone tmpfile tmpnam tolower tolower_l toupper toupper_l towctrans towctrans_l towlower towlower_l towupper towupper_l trunc truncate truncf truncl tsearch ttyname ttyname_r twalk tzname tzset umask uname ungetc ungetwc unlink unlinkat unlockpt unsetenv uselocale utime utimensat utimes va_arg va_copy va_end va_start vdprintf vfprintf vfscanf vfwprintf vfwscanf vprintf vscanf vsnprintf vsprintf vsscanf vswprintf vswscanf vwprintf vwscanf wait waitpid wcpcpy wcpncpy wcrtomb wcscasecmp wcscasecmp_l wcscat wcschr wcscmp wcscoll wcscoll_l wcscpy wcscspn wcsdup wcsftime wcslen wcsncasecmp wcsncasecmp_l wcsncat wcsncmp wcsncpy wcsnlen wcsnrtombs wcspbrk wcsrchr wcsrtombs wcsspn wcsstr wcstod wcstof wcstoimax wcstok wcstol wcstold wcstoll wcstombs wcstoul wcstoull wcstoumax wcswidth wcsxfrm wcsxfrm_l wctob wctomb wctrans wctrans_l wctype wctype_l wcwidth wmemchr wmemcmp wmemcpy wmemmove wmemset wordexp wordfree wprintf write writev wscanf y0 y1 yn __b64_ntop __b64_pton arc4random arc4random_addrandom arc4random_buf arc4random_stir arc4random_uniform bindresvport bindresvport_sa cfmakeraw cfsetspeed clearerr_unlocked daemon dn_comp dn_expand dn_skipname drem eaccess endusershell err errx explicit_bzero feof_unlocked ferror_unlocked fflush_unlocked fileno_unlocked fgetc_unlocked finite finitef finitel fiprintf flock (see chapter "Implementation Notes") fls flsl flsll forkpty fpurge fputc_unlocked fread_unlocked freeifaddrs fstatfs fts_children fts_close fts_get_clientptr fts_get_stream fts_open fts_read fts_set fts_set_clientptr funopen futimes fwrite_unlocked gamma gamma_r gammaf gammaf_r getdtablesize getgrouplist getifaddrs getloadavg getpagesize getpeereid getprogname getusershell herror hstrerror inet_aton inet_makeaddr inet_netof inet_network initgroups iruserok iruserok_sa issetugid login login_tty logout logwtmp madvise mkstemps openpty qsort_r (see chapter "Implementation Notes") rcmd rcmd_af reallocarray reallocf res_close res_init res_mkquery res_nclose res_ninit res_nmkquery res_nquery res_nquerydomain res_nsearch res_nsend res_query res_querydomain res_search res_send revoke rexec rpmatch rresvport rresvport_af ruserok sbrk setbuffer setgroups sethostname setlinebuf setpassent setprogname settimeofday setusershell statfs strcasestr strlcat strlcpy strsep timingsafe_bcmp timingsafe_memcmp updwtmp valloc verr verrx vhangup (see chapter "Implementation Notes") vsyslog vwarn vwarnx wait3 wait4 warn warnx wcslcat wcslcpy __mempcpy accept4 argz_add argz_add_sep argz_append argz_count argz_create argz_create_sep argz_delete argz_extract argz_insert argz_next argz_replace argz_stringify asnprintf asprintf asprintf_r basename (see chapter "Implementation Notes") canonicalize_file_name clog10 clog10f clog10l crypt_r (available in external "crypt" library) dladdr (see chapter "Implementation Notes") dremf dup3 envz_add envz_entry envz_get envz_merge envz_remove envz_strip error error_at_line euidaccess execvpe exp10 exp10f exp10l fcloseall fcloseall_r fedisableexcept feenableexcept fegetexcept fegetprec fesetprec ffsl ffsll fgets_unlocked fgetwc_unlocked fgetws_unlocked fgetxattr flistxattr fopencookie fputs_unlocked fputwc_unlocked fputws_unlocked fremovexattr fsetxattr get_avphys_pages get_current_dir_name get_nprocs get_nprocs_conf get_phys_pages getmntent_r getopt_long getopt_long_only getpt getwc_unlocked getwchar_unlocked getxattr lgetxattr listxattr llistxattr lremovexattr lsetxattr memmem mempcpy memrchr mkostemp mkostemps pipe2 pow10 pow10f pow10l ppoll pthread_getattr_np pthread_getname_np pthread_setname_np pthread_sigqueue ptsname_r putwc_unlocked putwchar_unlocked renameat2 (see chapter "Implementation Notes") qsort_r (see chapter "Implementation Notes") quotactl rawmemchr removexattr scandirat setxattr sincos sincosf sincosl strchrnul strptime_l strtod_l strtof_l strtol_l strtold_l strtoll_l strtoul_l strtoull_l strverscmp sysinfo tdestroy timegm timelocal toascii_l updwtmpx utmpxname vasnprintf vasprintf vasprintf_r versionsort wcsftime_l wcstod_l wcstof_l wcstol_l wcstold_l wcstoll_l wcstoul_l wcstoull_l wmempcpy __fbufsize __flbf __fpending __fpurge __freadable __freading __fsetlocking __fwritable __fwriting acl aclcheck aclfrommode aclfrompbits aclfromtext aclsort acltomode acltopbits acltotext endmntent facl futimesat getmntent memalign setmntent xdr_array (available in external "libtirpc" library) xdr_bool (available in external "libtirpc" library) xdr_bytes (available in external "libtirpc" library) xdr_char (available in external "libtirpc" library) xdr_double (available in external "libtirpc" library) xdr_enum (available in external "libtirpc" library) xdr_float (available in external "libtirpc" library) xdr_free (available in external "libtirpc" library) xdr_hyper (available in external "libtirpc" library) xdr_int (available in external "libtirpc" library) xdr_int16_t (available in external "libtirpc" library) xdr_int32_t (available in external "libtirpc" library) xdr_int64_t (available in external "libtirpc" library) xdr_int8_t (available in external "libtirpc" library) xdr_long (available in external "libtirpc" library) xdr_longlong_t (available in external "libtirpc" library) xdr_netobj (available in external "libtirpc" library) xdr_opaque (available in external "libtirpc" library) xdr_pointer (available in external "libtirpc" library) xdr_reference (available in external "libtirpc" library) xdr_short (available in external "libtirpc" library) xdr_sizeof (available in external "libtirpc" library) xdr_string (available in external "libtirpc" library) xdr_u_char (available in external "libtirpc" library) xdr_u_hyper (available in external "libtirpc" library) xdr_u_int (available in external "libtirpc" library) xdr_u_int16_t (available in external "libtirpc" library) xdr_u_int32_t (available in external "libtirpc" library) xdr_u_int64_t (available in external "libtirpc" library) xdr_u_int8_t (available in external "libtirpc" library) xdr_u_long (available in external "libtirpc" library) xdr_u_longlong_t (available in external "libtirpc" library) xdr_u_short (available in external "libtirpc" library) xdr_uint16_t (available in external "libtirpc" library) xdr_uint32_t (available in external "libtirpc" library) xdr_uint64_t (available in external "libtirpc" library) xdr_uint8_t (available in external "libtirpc" library) xdr_union (available in external "libtirpc" library) xdr_vector (available in external "libtirpc" library) xdr_void (available in external "libtirpc" library) xdr_wrapstring (available in external "libtirpc" library) xdrmem_create (available in external "libtirpc" library) xdrrec_create (available in external "libtirpc" library) xdrrec_endofrecord (available in external "libtirpc" library) xdrrec_eof (available in external "libtirpc" library) xdrrec_skiprecord (available in external "libtirpc" library) __xdrrec_getrec (available in external "libtirpc" library) __xdrrec_setnonblock (available in external "libtirpc" library) xdrstdio_create (available in external "libtirpc" library) aligned_alloc (ISO C11) at_quick_exit (ISO C11) quick_exit (ISO C11) bcmp (POSIX.1-2001, SUSv3) bcopy (SUSv3) bzero (SUSv3) chroot (SUSv2) (see chapter "Implementation Notes") clock_setres (QNX, VxWorks) (see chapter "Implementation Notes") cuserid (POSIX.1-1988, SUSv2) ecvt (SUSv3) endutent (XPG2) fcvt (SUSv3) ftime (SUSv3) gcvt (SUSv3) getcontext (SUSv3) gethostbyaddr (SUSv3) gethostbyname (SUSv3) gethostbyname2 (first defined in BIND 4.9.4) getpass (SUSv2) getutent (XPG2) getutid (XPG2) getutline (XPG2) getw (SVID) getwd (SUSv3) h_errno (SUSv3) index (SUSv3) makecontext (SUSv3) mallinfo (SVID) mallopt (SVID) mktemp (SUSv3) on_exit (SunOS) pthread_attr_getstackaddr (SUSv3) pthread_attr_setstackaddr (SUSv3) pthread_continue (XPG2) pthread_getsequence_np (Tru64) pthread_suspend (XPG2) pthread_yield (POSIX.1c drafts) pututline (XPG2) putw (SVID) rindex (SUSv3) scalb (SUSv3) setcontext (SUSv3) setutent (XPG2) stime (SVID) swapcontext (SUSv3) sys_errlist (BSD) sys_nerr (BSD) sys_siglist (BSD) toascii (SUSv3) ttyslot (SUSv2) ualarm (SUSv3) usleep (SUSv3) utmpname (XPG2) vfork (SUSv3) (see chapter "Implementation Notes") aio_cancel aio_error aio_fsync aio_read aio_return aio_suspend aio_write endnetent fattach fmtmsg getdate getdate_err gethostent getmsg getnetbyaddr getnetbyname getnetent getpmsg isastream lio_listio mlockall munlockall posix_mem_offset posix_trace[...] posix_typed_[...] pthread_mutexattr_getrobust pthread_mutexattr_setrobust pthread_mutex_consistent putmsg setnetent timer_getoverrun ulimit waitid chroot only emulates a chroot function call by keeping track of the current root and accomodating this in the file related function calls. A real chroot functionality is not supported by Windows however. clock_nanosleep currently supports only CLOCK_REALTIME and CLOCK_MONOTONIC. clock_setres, clock_settime, and timer_create currently support only CLOCK_REALTIME. POSIX file locks via fcntl or lockf, as well as BSD flock locks are advisory locks. They don't interact with Windows mandatory locks, nor do POSIX fcntl locks interfere with BSD flock locks or vice versa. BSD file locks created via flock are only propagated to the direct parent process, not to grand parents or sibling processes. The locks are only valid in the creating process, its parent process, and subsequently started child processes sharing the same file descriptor. In very rare circumstances an application would want to use Windows mandatory locks to interact with non-Cygwin Windows processes accessing the same file (databases, etc). For these purposes, the entire locking mechanism (fcntl/flock/lockf) can be switched to Windows mandatory locks on a per-descriptor/per-process basis. For this purpose, use the call fcntl (fd, F_LCK_MANDATORY, 1); After that, all file locks on this descriptor will follow Windows mandatory record locking semantics: Locks are per-descriptor/per-process; locks are not propagated to child processes, not even via execve; no atomic replacement of read locks with write locks and vice versa on the same descriptor; locks have to be unlocked exactly as they have been locked. fpclassify, isfinite, isgreater, isgreaterequal, isinf, isless, islessequal, islessgreater, isnan, isnormal, isunordered, and signbit only support float and double arguments, not long double arguments. getitimer and setitimer only support ITIMER_REAL for now. link will fail on FAT, FAT32, and other filesystems not supporting hardlinks, just as on Linux. lseek only works properly on files opened in binary mode. On files opened in textmode (via mount mode or explicit open flag) its positioning is potentially unreliable. setuid is only safe against reverting the user switch after a call to one of the exec(2) functions took place. Windows doesn't support a non-revertable user switch within the context of Win32 processes. vfork just calls fork. vhangup and revoke always return -1 and set errno to ENOSYS. grantpt and unlockpt always just return 0. The XSI IPC functions semctl, semget, semop, shmat, shmctl, shmdt, shmget, msgctl, msgget, msgrcv and msgsnd are only available when cygserver is running. The Linux-specific function quotactl only implements what works on Windows: Windows only supports user block quotas on NTFS, no group quotas, no inode quotas, no time constraints. qsort_r is available in both BSD and GNU flavors, depending on whether _BSD_SOURCE or _GNU_SOURCE is defined when compiling. The Linux-specific function renameat2 only supports the RENAME_NOREPLACE flag. basename is available in both POSIX and GNU flavors, depending on whether libgen.h is included or not. sigpause is available in both BSD and SysV/XSI flavors, depending on whether _XOPEN_SOURCE is defined when compiling. strerror_r is available in both POSIX and GNU flavors, depending on whether _GNU_SOURCE is defined when compiling. dladdr always sets the Dl_info members dli_sname and dli_saddr to NULL, indicating no symbol matching addr could be found.