| Copyright | (c) The University of Glasgow 2002 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | libraries@haskell.org |
| Stability | provisional |
| Portability | non-portable (requires POSIX) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
System.Posix.IO.ByteString
Description
POSIX IO support. These types and functions correspond to the unix functions open(2), close(2), etc. For more portable functions which are more like fopen(3) and friends from stdio.h, see System.IO.
Synopsis
- stdInput :: Fd
- stdOutput :: Fd
- stdError :: Fd
- data OpenMode
- data OpenFileFlags = OpenFileFlags {}
- defaultFileFlags :: OpenFileFlags
- openFd :: RawFilePath -> OpenMode -> OpenFileFlags -> IO Fd
- openFdAt :: Maybe Fd -> RawFilePath -> OpenMode -> OpenFileFlags -> IO Fd
- createFile :: RawFilePath -> FileMode -> IO Fd
- createFileAt :: Maybe Fd -> RawFilePath -> FileMode -> IO Fd
- closeFd :: Fd -> IO ()
- fdRead :: Fd -> ByteCount -> IO ByteString
- fdWrite :: Fd -> ByteString -> IO ByteCount
- fdReadBuf :: Fd -> Ptr Word8 -> ByteCount -> IO ByteCount
- fdWriteBuf :: Fd -> Ptr Word8 -> ByteCount -> IO ByteCount
- fdSeek :: Fd -> SeekMode -> FileOffset -> IO FileOffset
- data FdOption
- queryFdOption :: Fd -> FdOption -> IO Bool
- setFdOption :: Fd -> FdOption -> Bool -> IO ()
- type FileLock = (LockRequest, SeekMode, FileOffset, FileOffset)
- data LockRequest
- getLock :: Fd -> FileLock -> IO (Maybe (ProcessID, FileLock))
- setLock :: Fd -> FileLock -> IO ()
- waitToSetLock :: Fd -> FileLock -> IO ()
- createPipe :: IO (Fd, Fd)
- dup :: Fd -> IO Fd
- dupTo :: Fd -> Fd -> IO Fd
- handleToFd :: Handle -> IO Fd
- fdToHandle :: Fd -> IO Handle
Input / Output
Standard file descriptors
Opening and closing files
Instances
data OpenFileFlags Source #
Correspond to some of the int flags from C's fcntl.h.
Constructors
Fields
- append :: Bool
O_APPEND
- exclusive :: Bool
- noctty :: Bool
O_NOCTTY
- nonBlock :: Bool
O_NONBLOCK
- trunc :: Bool
O_TRUNC
- nofollow :: Bool
O_NOFOLLOW
Since: 2.8.0.0
- creat :: Maybe FileMode
O_CREAT
Since: 2.8.0.0
- cloexec :: Bool
O_CLOEXEC
Since: 2.8.0.0
- directory :: Bool
O_DIRECTORY
Since: 2.8.0.0
- sync :: Bool
O_SYNC
Since: 2.8.0.0
Instances
Instances details
Instance details
Defined in System.Posix.IO.Common
Methods
readsPrec :: Int -> ReadS OpenFileFlags #
readList :: ReadS [OpenFileFlags] #
Instance details
Defined in System.Posix.IO.Common
Methods
showsPrec :: Int -> OpenFileFlags -> ShowS #
show :: OpenFileFlags -> String #
showList :: [OpenFileFlags] -> ShowS #
Instance details
Defined in System.Posix.IO.Common
Methods
(==) :: OpenFileFlags -> OpenFileFlags -> Bool #
(/=) :: OpenFileFlags -> OpenFileFlags -> Bool #
Instance details
Defined in System.Posix.IO.Common
Methods
compare :: OpenFileFlags -> OpenFileFlags -> Ordering #
(<) :: OpenFileFlags -> OpenFileFlags -> Bool #
(<=) :: OpenFileFlags -> OpenFileFlags -> Bool #
(>) :: OpenFileFlags -> OpenFileFlags -> Bool #
(>=) :: OpenFileFlags -> OpenFileFlags -> Bool #
max :: OpenFileFlags -> OpenFileFlags -> OpenFileFlags #
min :: OpenFileFlags -> OpenFileFlags -> OpenFileFlags #
defaultFileFlags :: OpenFileFlags Source #
Default values for the OpenFileFlags type.
Each field of OpenFileFlags is either False or Nothing
respectively.
openFd :: RawFilePath -> OpenMode -> OpenFileFlags -> IO Fd Source #
Arguments
Pathname to open
Read-only, read-write or write-only
Append, exclusive, truncate, etc.
Open a file relative to an optional directory file descriptor.
Directory file descriptors can be used to avoid some race conditions when navigating changing directory trees, or to retain access to a portion of the directory tree that would otherwise become inaccessible after dropping privileges.
createFile :: RawFilePath -> FileMode -> IO Fd Source #
Create and open a file for write-only, with default flags, relative an optional directory file-descriptor.
Directory file descriptors can be used to avoid some race conditions when navigating changing directory trees, or to retain access to a portion of the directory tree that would otherwise become inaccessible after dropping privileges.
closeFd :: Fd -> IO () Source #
Close this file descriptor. May throw an exception if this is an invalid descriptor.
Reading/writing data
Programmers using the fdRead and fdWrite API should be aware that
EAGAIN exceptions may occur for non-blocking IO!
Read data from an Fd and return it as a ByteString .
Throws an exception if this is an invalid descriptor, or EOF has been
reached.
fdWrite :: Fd -> ByteString -> IO ByteCount Source #
Write a ByteString to an Fd .
Read data from an Fd into memory. This is exactly equivalent
to the POSIX read function.
Write data from memory to an Fd . This is exactly equivalent
to the POSIX write function.
Seeking
fdSeek :: Fd -> SeekMode -> FileOffset -> IO FileOffset Source #
May throw an exception if this is an invalid descriptor.
File options
Constructors
O_APPEND
FD_CLOEXEC
O_NONBLOCK
O_SYNC
queryFdOption :: Fd -> FdOption -> IO Bool Source #
May throw an exception if this is an invalid descriptor.
setFdOption :: Fd -> FdOption -> Bool -> IO () Source #
May throw an exception if this is an invalid descriptor.
Locking
type FileLock = (LockRequest, SeekMode, FileOffset, FileOffset) Source #
getLock :: Fd -> FileLock -> IO (Maybe (ProcessID, FileLock)) Source #
May throw an exception if this is an invalid descriptor.
setLock :: Fd -> FileLock -> IO () Source #
May throw an exception if this is an invalid descriptor.
waitToSetLock :: Fd -> FileLock -> IO () Source #
May throw an exception if this is an invalid descriptor.
Pipes
createPipe :: IO (Fd, Fd) Source #
The createPipe function creates a pair of connected file
descriptors. The first component is the fd to read from, the second
is the write end. Although pipes may be bidirectional, this
behaviour is not portable and programmers should use two separate
pipes for this purpose. May throw an exception if this is an
invalid descriptor.
Duplicating file descriptors
Converting file descriptors to/from Handles
handleToFd :: Handle -> IO Fd Source #
Extracts the Fd from a Handle . This function has the side effect
of closing the Handle (and flushing its write buffer, if necessary),
without closing the underlying Fd .
Warning: This means you take over ownership of the underlying Fd .
hClose on the Handle will no longer have any effect.
This will break common patterns to avoid file descriptor leaks,
such as using hClose in the cleanup action of Control.Exception.bracket,
making it a silent no-op.
Be sure to close the returned Fd yourself to not leak it.