By default your systems F_* and O_* constants (eg, F_DUPFD and
O_CREAT) and the FD_CLOEXEC constant are exported into your namespace.
You can request that the flock() constants (LOCK_SH, LOCK_EX, LOCK_NB
and LOCK_UN) be provided by using the tag :flock. See Exporter.
You can request that the old constants (FAPPEND, FASYNC, FCREAT,
FDEFER, FEXCL, FNDELAY, FNONBLOCK, FSYNC, FTRUNC) be provided for
compatibility reasons by using the tag :Fcompat. For new
applications the newer versions of these constants are suggested
(O_APPEND, O_ASYNC, O_CREAT, O_DEFER, O_EXCL, O_NDELAY, O_NONBLOCK,
For ease of use also the SEEK_* constants (for seek() and sysseek(),
e.g. SEEK_END) and the S_I* constants (for chmod() and stat()) are
available for import. They can be imported either separately or using
the tags :seek and :mode.
Please refer to your native fcntl(2), open(2), fseek(3), lseek(2)
(equal to Perls seek() and sysseek(), respectively), and chmod(2)
documentation to see what constants are implemented in your system.
See perlopentut to learn about the uses of the O_* constants
See seek in perlfunc and sysseek in perlfunc about the SEEK_* constants.
See stat in perlfunc about the S_I* constants.