# module Fcntl

### Constants

FD_CLOEXEC

  `FD_CLOEXEC`

  the value of the close-on-exec flag.

F_DUP2FD

  `F_DUP2FD`

  It is a FreeBSD specific constant and equivalent to dup2 call.

F_DUP2FD_CLOEXEC

  `F_DUP2FD_CLOEXEC`

  It is a FreeBSD specific constant and acts similarly as `F_DUP2FD` but set the `FD_CLOEXEC` flag in addition.

F_DUPFD

  `F_DUPFD`

  Duplicate a file descriptor to the minimum unused file descriptor greater than or equal to the argument.

  The close-on-exec flag of the duplicated file descriptor is set. (Ruby uses F_DUPFD_CLOEXEC internally if available to avoid race condition. `F_SETFD` is used if F_DUPFD_CLOEXEC is not available.)

F_GETFD

  `F_GETFD`

  Read the close-on-exec flag of a file descriptor.

F_GETFL

  `F_GETFL`

  Get the file descriptor flags. This will be one or more of the O_* flags.

F_GETLK

  `F_GETLK`

  Determine whether a given region of a file is locked. This uses one of the F_*LK flags.

F_GETPIPE_SZ

  `F_GETPIPE_SZ`

  Return (as the function result) the capacity of the pipe referred to by fd.

F_RDLCK

  `F_RDLCK`

  Read lock for a region of a file

F_SETFD

  `F_SETFD`

  `Set` the close-on-exec flag of a file descriptor.

F_SETFL

  `F_SETFL`

  `Set` the file descriptor flags. This will be one or more of the O_* flags.

F_SETLK

  `F_SETLK`

  Acquire a lock on a region of a file. This uses one of the F_*LCK flags.

F_SETLKW

  `F_SETLKW`

  Acquire a lock on a region of a file, waiting if necessary. This uses one of the F_*LCK flags

F_SETPIPE_SZ

  `F_SETPIPE_SZ`

  Change the capacity of the pipe referred to by fd to be at least arg bytes.

F_UNLCK

  `F_UNLCK`

  Remove lock for a region of a file

F_WRLCK

  `F_WRLCK`

  Write lock for a region of a file

O_ACCMODE

  `O_ACCMODE`

  Mask to extract the read/write flags

O_APPEND

  `O_APPEND`

  Open the file in append mode

O_CREAT

  `O_CREAT`

  Create the file if it doesn’t exist

O_EXCL

  `O_EXCL`

  Used with `O_CREAT`, fail if the file exists

O_NDELAY

  `O_NDELAY`

  Open the file in non-blocking mode

O_NOCTTY

  `O_NOCTTY`

  Open TTY without it becoming the controlling TTY

O_NONBLOCK

  `O_NONBLOCK`

  Open the file in non-blocking mode

O_RDONLY

  `O_RDONLY`

  Open the file in read-only mode

O_RDWR

  `O_RDWR`

  Open the file in read-write mode

O_TRUNC

  `O_TRUNC`

  Truncate the file on open

O_WRONLY

  `O_WRONLY`

  Open the file in write-only mode.

VERSION