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@@ -198,38 +198,45 @@ handleStateVarWritingBiased (DuplexHandle _ _ writingVar) = writingVar |
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{-|
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Yields the result of another operation if that operation succeeded, and
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otherwise throws an exception that signals that the other operation failed
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- because a certain I/O subsystem is not in use.
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+ because some Haskell handle does not use an operating-system handle of a
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+ required type.
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-}
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-requiringSubsystem :: String
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- -- ^ The name of the required subsystem
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- -> Maybe a
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- -- ^ The result of the other operation if it succeeded
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- -> IO a
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-requiringSubsystem subsystemName
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- = maybe (ioException subsystemRequired) return
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+requiringOSHandleOfType :: String
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+ -- ^ The name of the operating-system handle type
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+ -> Maybe a
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+ {-^
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+ The result of the other operation if it succeeded
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+ -}
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+ -> IO a
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+requiringOSHandleOfType osHandleTypeName
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+ = maybe (ioException osHandleOfTypeRequired) return
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where
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- subsystemRequired :: IOException
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- subsystemRequired = IOError Nothing
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- IllegalOperation
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- ""
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- (subsystemName ++ " I/O subsystem required")
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- Nothing
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- Nothing
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+ osHandleOfTypeRequired :: IOException
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+ osHandleOfTypeRequired
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+ = IOError Nothing
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+ IllegalOperation
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+ ""
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+ ("handle does not use " ++ osHandleTypeName ++ "s")
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+ Nothing
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+ Nothing
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{-|
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- Obtains the POSIX file descriptor of a device if the POSIX I/O subsystem is
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- in use, and throws an exception otherwise.
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+ Obtains the POSIX file descriptor of a device if the device contains one,
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+ and throws an exception otherwise.
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-}
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getFileDescriptor :: Typeable d => d -> IO CInt
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-getFileDescriptor = requiringSubsystem "POSIX" . fmap fdFD . cast
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+getFileDescriptor = requiringOSHandleOfType "POSIX file descriptor" .
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+ fmap fdFD . cast
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{-|
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- Obtains the Windows handle of a device if the Windows I/O subsystem is in
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- use, and throws an exception otherwise.
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+ Obtains the Windows handle of a device if the device contains one, and
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+ throws an exception otherwise.
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-}
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getWindowsHandle :: Typeable d => d -> IO (Ptr ())
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-getWindowsHandle = requiringSubsystem "native" . toMaybeWindowsHandle where
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+getWindowsHandle = requiringOSHandleOfType "Windows handle" .
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+ toMaybeWindowsHandle
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+ where
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toMaybeWindowsHandle :: Typeable d => d -> Maybe (Ptr ())
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#if defined(mingw32_HOST_OS)
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@@ -257,7 +264,7 @@ getWindowsHandle = requiringSubsystem "native" . toMaybeWindowsHandle where |
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further operations on the handle are blocked to a degree that interference
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with this action is prevented.
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- If the I/O subsystem in use is not the POSIX one, an exception is thrown.
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+ If the handle does not use POSIX file descriptors, an exception is thrown.
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See [below](#with-ref-caveats) for caveats regarding this operation.
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-}
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@@ -275,7 +282,7 @@ withFileDescriptorReadingBiased = withOSHandle "withFileDescriptorReadingBiased" |
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further operations on the handle are blocked to a degree that interference
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with this action is prevented.
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- If the I/O subsystem in use is not the POSIX one, an exception is thrown.
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+ If the handle does not use POSIX file descriptors, an exception is thrown.
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See [below](#with-ref-caveats) for caveats regarding this operation.
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-}
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@@ -293,7 +300,7 @@ withFileDescriptorWritingBiased = withOSHandle "withFileDescriptorWritingBiased" |
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operations on the Haskell handle are blocked to a degree that interference
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with this action is prevented.
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- If the I/O subsystem in use is not the Windows one, an exception is thrown.
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+ If the Haskell handle does not use Windows handles, an exception is thrown.
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See [below](#with-ref-caveats) for caveats regarding this operation.
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-}
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@@ -311,7 +318,7 @@ withWindowsHandleReadingBiased = withOSHandle "withWindowsHandleReadingBiased" |
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operations on the Haskell handle are blocked to a degree that interference
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with this action is prevented.
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- If the I/O subsystem in use is not the Windows one, an exception is thrown.
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+ If the Haskell handle does not use Windows handles, an exception is thrown.
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See [below](#with-ref-caveats) for caveats regarding this operation.
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-}
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