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GHC.IO.Handle.FD | Portability | non-portable | Stability | internal | Maintainer | libraries@haskell.org |
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Description |
Handle operations implemented by file descriptors (FDs)
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Synopsis |
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Documentation |
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A handle managing input from the Haskell program's standard input channel.
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A handle managing output to the Haskell program's standard output channel.
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A handle managing output to the Haskell program's standard error channel.
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Computation openFile file mode allocates and returns a new, open
handle to manage the file file. It manages input if mode
is ReadMode, output if mode is WriteMode or AppendMode,
and both input and output if mode is ReadWriteMode.
If the file does not exist and it is opened for output, it should be
created as a new file. If mode is WriteMode and the file
already exists, then it should be truncated to zero length.
Some operating systems delete empty files, so there is no guarantee
that the file will exist following an openFile with mode
WriteMode unless it is subsequently written to successfully.
The handle is positioned at the end of the file if mode is
AppendMode, and otherwise at the beginning (in which case its
internal position is 0).
The initial buffer mode is implementation-dependent.
This operation may fail with:
- isAlreadyInUseError if the file is already open and cannot be reopened;
- isDoesNotExistError if the file does not exist; or
- isPermissionError if the user does not have permission to open the file.
Note: if you will be working with files containing binary data, you'll want to
be using openBinaryFile.
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Like openFile, but open the file in binary mode.
On Windows, reading a file in text mode (which is the default)
will translate CRLF to LF, and writing will translate LF to CRLF.
This is usually what you want with text files. With binary files
this is undesirable; also, as usual under Microsoft operating systems,
text mode treats control-Z as EOF. Binary mode turns off all special
treatment of end-of-line and end-of-file characters.
(See also hSetBinaryMode.)
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Turn an existing file descriptor into a Handle. This is used by
various external libraries to make Handles.
Makes a binary Handle. This is for historical reasons; it should
probably be a text Handle with the default encoding and newline
translation instead.
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Old API kept to avoid breaking clients
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The computation isEOF is identical to hIsEOF,
except that it works only on stdin.
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Produced by Haddock version 2.6.1 |