GHC.IO.BufferedIO
| Copyright | (c) The University of Glasgow 2008 |
|---|---|
| License | see libraries/base/LICENSE |
| Maintainer | ghc-devs@haskell.org |
| Stability | internal |
| Portability | non-portable (GHC Extensions) |
| Safe Haskell | Safe |
| Language | Haskell2010 |
Description
Class of buffered IO devices
class BufferedIO dev where Source
The purpose of BufferedIO is to provide a common interface for I/O devices that can read and write data through a buffer. Devices that implement BufferedIO include ordinary files, memory-mapped files, and bytestrings. The underlying device implementing a Handle must provide BufferedIO.
Minimal complete definition
newBuffer, fillReadBuffer, fillReadBuffer0, flushWriteBuffer, flushWriteBuffer0
Methods
newBuffer :: dev -> BufferState -> IO (Buffer Word8) Source
allocate a new buffer. The size of the buffer is at the discretion of the device; e.g. for a memory-mapped file the buffer will probably cover the entire file.
fillReadBuffer :: dev -> Buffer Word8 -> IO (Int, Buffer Word8) Source
reads bytes into the buffer, blocking if there are no bytes available. Returns the number of bytes read (zero indicates end-of-file), and the new buffer.
fillReadBuffer0 :: dev -> Buffer Word8 -> IO (Maybe Int, Buffer Word8) Source
reads bytes into the buffer without blocking. Returns the number of bytes read (Nothing indicates end-of-file), and the new buffer.
emptyWriteBuffer :: dev -> Buffer Word8 -> IO (Buffer Word8) Source
Prepares an empty write buffer. This lets the device decide how to set up a write buffer: the buffer may need to point to a specific location in memory, for example. This is typically used by the client when switching from reading to writing on a buffered read/write device.
There is no corresponding operation for read buffers, because before reading the client will always call fillReadBuffer.
flushWriteBuffer :: dev -> Buffer Word8 -> IO (Buffer Word8) Source
Flush all the data from the supplied write buffer out to the device. The returned buffer should be empty, and ready for writing.
flushWriteBuffer0 :: dev -> Buffer Word8 -> IO (Int, Buffer Word8) Source
Flush data from the supplied write buffer out to the device without blocking. Returns the number of bytes written and the remaining buffer.
Instances
| BufferedIO FD Source | Since: base-4.1.0.0 |
Defined in GHC.Internal.IO.FD MethodsnewBuffer :: FD -> BufferState -> IO (Buffer Word8) Source fillReadBuffer :: FD -> Buffer Word8 -> IO (Int, Buffer Word8) Source fillReadBuffer0 :: FD -> Buffer Word8 -> IO (Maybe Int, Buffer Word8) Source emptyWriteBuffer :: FD -> Buffer Word8 -> IO (Buffer Word8) Source flushWriteBuffer :: FD -> Buffer Word8 -> IO (Buffer Word8) Source flushWriteBuffer0 :: FD -> Buffer Word8 -> IO (Int, Buffer Word8) Source | |
readBuf :: RawIO dev => dev -> Buffer Word8 -> IO (Int, Buffer Word8) Source
readBufNonBlocking :: RawIO dev => dev -> Buffer Word8 -> IO (Maybe Int, Buffer Word8) Source
writeBuf :: RawIO dev => dev -> Buffer Word8 -> IO (Buffer Word8) Source
writeBufNonBlocking :: RawIO dev => dev -> Buffer Word8 -> IO (Int, Buffer Word8) Source
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/9.14.1/docs/libraries/base-4.22.0.0-66f8/GHC-IO-BufferedIO.html
