| Copyright | (c) The University of Glasgow 2002 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | [email protected] |
| Stability | provisional |
| Portability | non-portable (requires POSIX) |
| Safe Haskell | Safe |
| Language | Haskell2010 |
System.Posix.IO
Contents
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.
- stdInput :: Fd
- stdOutput :: Fd
- stdError :: Fd
- data OpenMode
- data OpenFileFlags = OpenFileFlags {}
- defaultFileFlags :: OpenFileFlags
- openFd :: FilePath -> OpenMode -> Maybe FileMode -> OpenFileFlags -> IO Fd
- createFile :: FilePath -> FileMode -> IO Fd
- closeFd :: Fd -> IO ()
- fdRead :: Fd -> ByteCount -> IO (String, ByteCount)
- fdWrite :: Fd -> String -> 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
data OpenFileFlags Source #
Correspond to some of the int flags from C's fcntl.h.
defaultFileFlags :: OpenFileFlags Source #
Default values for the OpenFileFlags type. False for each of
append, exclusive, noctty, nonBlock, and trunc.
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!
Arguments
| :: Fd | |
| -> Ptr Word8 | Memory in which to put the data |
| -> ByteCount | Maximum number of bytes to read |
| -> IO ByteCount | Number of bytes read (zero for EOF) |
Read data from an Fd into memory. This is exactly equivalent
to the POSIX read function.
Arguments
| :: Fd | |
| -> Ptr Word8 | Memory containing the data to write |
| -> ByteCount | Maximum number of bytes to write |
| -> IO ByteCount | Number of bytes written |
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
| AppendOnWrite | O_APPEND |
| CloseOnExec | FD_CLOEXEC |
| NonBlockingRead | O_NONBLOCK |
| SynchronousWrites | 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.
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.