module Fcntl
Fcntl loads the constants defined in the system's <fcntl.h> C header file, and used with both the fcntl(2) and open(2) POSIX system calls.
To perform a fcntl(2) operation, use IO::fcntl.
To perform an open(2) operation, use IO.sysopen.
The set of operations and constants available depends upon specific operating system. Some values listed below may not be supported on your system.
See your fcntl(2) man page for complete details.
Open /tmp/tempfile as a write-only file that is created if it doesn't exist:
require 'fcntl' fd = IO.sysopen('/tmp/tempfile', Fcntl::O_WRONLY | Fcntl::O_EXCL | Fcntl::O_CREAT) f = IO.open(fd) f.syswrite("TEMP DATA") f.close
Get the flags on file s
:
m = s.fcntl(Fcntl::F_GETFL, 0)
Set the non-blocking flag on f
in
addition to the existing flags in m
.
f.fcntl(Fcntl::F_SETFL, Fcntl::O_NONBLOCK|m)
Constants
- FD_CLOEXEC
-
the value of the close-on-exec flag.
- F_DUPFD
-
Duplicate a file descriptor to the mimimum 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
-
Read the close-on-exec flag of a file descriptor.
- F_GETFL
-
Get the file descriptor flags. This will be one or more of the O_* flags.
- F_GETLK
-
Determine whether a given region of a file is locked. This uses one of the F_*LK flags.
- F_RDLCK
-
Read lock for a region of a file
- F_SETFD
-
Set the close-on-exec flag of a file descriptor.
- F_SETFL
-
Set the file descriptor flags. This will be one or more of the O_* flags.
- F_SETLK
-
Acquire a lock on a region of a file. This uses one of the F_*LCK flags.
- F_SETLKW
-
Acquire a lock on a region of a file, waiting if necessary. This uses one of the F_*LCK flags
- F_UNLCK
-
Remove lock for a region of a file
- F_WRLCK
-
Write lock for a region of a file
- O_ACCMODE
-
Mask to extract the read/write flags
- O_APPEND
-
Open the file in append mode
- O_CREAT
-
Create the file if it doesn't exist
- O_EXCL
-
Used with O_CREAT, fail if the file exists
- O_NDELAY
-
Open the file in non-blocking mode
- O_NOCTTY
-
Open TTY without it becoming the controlling TTY
- O_NONBLOCK
-
Open the file in non-blocking mode
- O_RDONLY
-
Open the file in read-only mode
- O_RDWR
-
Open the file in read-write mode
- O_TRUNC
-
Truncate the file on open
- O_WRONLY
-
Open the file in write-only mode.