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
clock_nanosleep currently supports only
CLOCK_REALTIME and CLOCK_MONOTONIC.
currently support only CLOCK_REALTIME.
POSIX file locks via
lockf, as well as BSD
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
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
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.
only support float and double arguments, not long double arguments.
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
vfork just calls
return -1 and set errno to ENOSYS.
unlockpt always just return 0.
The XSI IPC functions
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.