[Git][ghc/ghc][wip/jeltsch/obtaining-os-handles] 3 commits: Export labelThread from Control.Concurrent

Wolfgang Jeltsch pushed to branch wip/jeltsch/obtaining-os-handles at Glasgow Haskell Compiler / GHC Commits: 917ab8ff by Oleg Grenrus at 2026-01-23T10:52:55-05:00 Export labelThread from Control.Concurrent - - - - - 3f5e8d80 by Cheng Shao at 2026-01-23T10:53:37-05:00 ci: only push perf notes on master/release branches This patch fixes push_perf_notes logic in ci.sh to only push perf notes on master/release branches. We used to unconditionally push perf notes even in MRs, but the perf numbers in the wip branches wouldn't be used as baseline anyway, plus this is causing a space leak in the ghc-performance-notes repo. See #25317 for the perf notes repo size problem. Co-authored-by: Codex <codex@openai.com> - - - - - 30e249fe by Wolfgang Jeltsch at 2026-01-24T10:27:27+02:00 Add operations for obtaining operating-system handles This contribution implements CLC proposal #369. It adds operations for obtaining POSIX file descriptors and Windows handles that underlie Haskell handles. Those operating system handles can also be obtained without such additional operations, but this is more involved and, more importantly, requires using internals. - - - - - 25 changed files: - .gitlab/ci.sh - libraries/base/base.cabal.in - libraries/base/changelog.md - libraries/base/src/Control/Concurrent.hs - + libraries/base/src/System/IO/OS.hs - libraries/base/src/System/Timeout.hs - libraries/base/tests/IO/all.T - + libraries/base/tests/IO/osHandles001FileDescriptors.hs - + libraries/base/tests/IO/osHandles001FileDescriptors.stdout - + libraries/base/tests/IO/osHandles001WindowsHandles.hs - + libraries/base/tests/IO/osHandles001WindowsHandles.stdout - + libraries/base/tests/IO/osHandles002FileDescriptors.hs - + libraries/base/tests/IO/osHandles002FileDescriptors.stderr - + libraries/base/tests/IO/osHandles002FileDescriptors.stdin - + libraries/base/tests/IO/osHandles002FileDescriptors.stdout - + libraries/base/tests/IO/osHandles002WindowsHandles.hs - + libraries/base/tests/IO/osHandles002WindowsHandles.stderr - + libraries/base/tests/IO/osHandles002WindowsHandles.stdin - + libraries/base/tests/IO/osHandles002WindowsHandles.stdout - libraries/ghc-internal/ghc-internal.cabal.in - + libraries/ghc-internal/src/GHC/Internal/System/IO/OS.hs - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/base-exports.stdout-ws-32 Changes: ===================================== .gitlab/ci.sh ===================================== @@ -493,6 +493,11 @@ function fetch_perf_notes() { } function push_perf_notes() { + if [[ "${CI_COMMIT_BRANCH:-}" != "master" ]] && [[ ! "${CI_COMMIT_BRANCH:-}" =~ ghc-[0-9]+\.[0-9]+ ]]; then + info "Perf notes are only pushed on master/release branches" + return + fi + if [[ -z "${TEST_ENV:-}" ]]; then return fi ===================================== libraries/base/base.cabal.in ===================================== @@ -255,6 +255,7 @@ Library , System.Exit , System.IO , System.IO.Error + , System.IO.OS , System.Mem , System.Mem.StableName , System.Posix.Internals ===================================== libraries/base/changelog.md ===================================== @@ -22,6 +22,8 @@ * `GHC.Conc.throwSTM` and `GHC.Conc.Sync.throwSTM` now carry a `HasCallStack` constraint and attach a `Backtrace` annotation to the thrown exception. ([GHC #25365](https://gitlab.haskell.org/ghc/ghc/-/issues/25365)) * `GHC.Conc.catchSTM` and `GHC.Conc.Sync.catchSTM` now attach `WhileHandling` annotation to exceptions thrown from the handler. ([GHC #25365](https://gitlab.haskell.org/ghc/ghc/-/issues/25365)) * Remove `GHC.JS.Prim.Internal.Build`, as per [CLC #329](https://github.com/haskell/core-libraries-committee/issues/329) + * Export `labelThread` from `Control.Concurrent`.([CLC proposal #376](https://github.com/haskell/core-libraries-committee/issues/376)) + * Add a new module `System.IO.OS` with operations for obtaining operating-system handles (file descriptors, Windows handles). ([CLC proposal #369](https://github.com/haskell/core-libraries-committee/issues/369)) ## 4.22.0.0 *TBA* * Shipped with GHC 9.14.1 ===================================== libraries/base/src/Control/Concurrent.hs ===================================== @@ -82,6 +82,9 @@ module Control.Concurrent ( -- * Weak references to ThreadIds mkWeakThreadId, + -- * Thread debugging + labelThread, + -- * GHC's implementation of concurrency -- |This section describes features specific to GHC's ===================================== libraries/base/src/System/IO/OS.hs ===================================== @@ -0,0 +1,62 @@ +{-# LANGUAGE Safe #-} + +{-| + This module bridges between Haskell handles and underlying operating-system + features. +-} +module System.IO.OS +( + -- * Obtaining file descriptors and Windows handles + withFileDescriptorReadingBiased, + withFileDescriptorWritingBiased, + withWindowsHandleReadingBiased, + withWindowsHandleWritingBiased, + withFileDescriptorReadingBiasedRaw, + withFileDescriptorWritingBiasedRaw, + withWindowsHandleReadingBiasedRaw, + withWindowsHandleWritingBiasedRaw + + -- ** Caveats + -- $with-ref-caveats +) +where + +import GHC.Internal.System.IO.OS + ( + withFileDescriptorReadingBiased, + withFileDescriptorWritingBiased, + withWindowsHandleReadingBiased, + withWindowsHandleWritingBiased, + withFileDescriptorReadingBiasedRaw, + withFileDescriptorWritingBiasedRaw, + withWindowsHandleReadingBiasedRaw, + withWindowsHandleWritingBiasedRaw + ) + +-- ** Caveats + +{-$with-ref-caveats + #with-ref-caveats#There are the following caveats regarding the above + operations: + + * Flushing of buffers can fail if the given handle is readable but not + seekable. + + * If one of these operations is performed as part of an action executed by + 'System.IO.Unsafe.unsafePerformIO', + 'System.IO.Unsafe.unsafeInterleaveIO', or one of their “dupable” + variants and the user-provided action receives an asychnchronous + exception and does not catch it, then the following happens: + + - Before the overall computation is suspended, the blocking of handle + operations is removed. + + - When the computation is later resumed due to another evaluation + attempt, the blocking of handle operations is reinstantiated, the + Haskell-managed buffers are flushed again, and the user-provided + action is run from the beginning. + + Repeating the previously executed part of the user-provided action + cannot be avoided apparently. See the @[async]@ note in the source code + of "GHC.Internal.IO.Handle.Internals" for further explanation. +-} ===================================== libraries/base/src/System/Timeout.hs ===================================== @@ -29,7 +29,6 @@ import GHC.Internal.Control.Exception (Exception(..), handleJust, bracket, asyncExceptionToException, asyncExceptionFromException) import GHC.Internal.Data.Unique (Unique, newUnique) -import GHC.Conc (labelThread) import Prelude -- $setup ===================================== libraries/base/tests/IO/all.T ===================================== @@ -186,3 +186,15 @@ test('T17912', [only_ways(['threaded1']), when(opsys('mingw32'),expect_broken(1) test('T18832', only_ways(['threaded1']), compile_and_run, ['']) test('mkdirExists', [exit_code(1), when(opsys('mingw32'), ignore_stderr)], compile_and_run, ['']) + +test('osHandles001FileDescriptors', omit_ways(['winio', 'winio_threaded']), compile_and_run, ['']) +test('osHandles001WindowsHandles', only_ways(['winio', 'winio_threaded']), compile_and_run, ['']) +test('osHandles002FileDescriptors', when(opsys('mingw32'), skip), compile_and_run, ['']) +test('osHandles002WindowsHandles', only_ways(['winio', 'winio_threaded']), compile_and_run, ['']) +# It would be good to let `osHandles002FileDescriptors` run also on +# Windows with the file-descriptor-based I/O manager. However, this +# test, as it is currently implemented, requires the `unix` package. +# That said, `UCRT.DLL`, which is used by GHC-generated Windows +# executables, emulates part of POSIX, enough for this test. As a +# result, this test could be generalized to also supporting Windows, but +# this would likely involve creating bindings to C code. ===================================== libraries/base/tests/IO/osHandles001FileDescriptors.hs ===================================== @@ -0,0 +1,23 @@ +{-# LANGUAGE TypeApplications #-} + +import Control.Monad (mapM_) +import Control.Exception (SomeException, try) +import System.IO (stdin, stdout, stderr) +import System.IO.OS + ( + withFileDescriptorReadingBiasedRaw, + withFileDescriptorWritingBiasedRaw, + withWindowsHandleReadingBiasedRaw, + withWindowsHandleWritingBiasedRaw + ) + +main :: IO () +main = mapM_ ((>>= print) . try @SomeException) $ + [ + withFileDescriptorReadingBiasedRaw stdin (return . show), + withFileDescriptorWritingBiasedRaw stdout (return . show), + withFileDescriptorWritingBiasedRaw stderr (return . show), + withWindowsHandleReadingBiasedRaw stdin (return . const "_"), + withWindowsHandleWritingBiasedRaw stdout (return . const "_"), + withWindowsHandleWritingBiasedRaw stderr (return . const "_") + ] ===================================== libraries/base/tests/IO/osHandles001FileDescriptors.stdout ===================================== @@ -0,0 +1,6 @@ +Right "0" +Right "1" +Right "2" +Left <stdin>: withWindowsHandleReadingBiasedRaw: inappropriate type (handle does not use Windows handles) +Left <stdout>: withWindowsHandleWritingBiasedRaw: inappropriate type (handle does not use Windows handles) +Left <stderr>: withWindowsHandleWritingBiasedRaw: inappropriate type (handle does not use Windows handles) ===================================== libraries/base/tests/IO/osHandles001WindowsHandles.hs ===================================== @@ -0,0 +1,23 @@ +{-# LANGUAGE TypeApplications #-} + +import Control.Monad (mapM_) +import Control.Exception (SomeException, try) +import System.IO (stdin, stdout, stderr) +import System.IO.OS + ( + withFileDescriptorReadingBiasedRaw, + withFileDescriptorWritingBiasedRaw, + withWindowsHandleReadingBiasedRaw, + withWindowsHandleWritingBiasedRaw + ) + +main :: IO () +main = mapM_ ((>>= print) . try @SomeException) $ + [ + withFileDescriptorReadingBiasedRaw stdin (return . show), + withFileDescriptorWritingBiasedRaw stdout (return . show), + withFileDescriptorWritingBiasedRaw stderr (return . show), + withWindowsHandleReadingBiasedRaw stdin (return . const "_"), + withWindowsHandleWritingBiasedRaw stdout (return . const "_"), + withWindowsHandleWritingBiasedRaw stderr (return . const "_") + ] ===================================== libraries/base/tests/IO/osHandles001WindowsHandles.stdout ===================================== @@ -0,0 +1,6 @@ +Left <stdin>: withFileDescriptorReadingBiasedRaw: inappropriate type (handle does not use file descriptors) +Left <stdout>: withFileDescriptorWritingBiasedRaw: inappropriate type (handle does not use file descriptors) +Left <stderr>: withFileDescriptorWritingBiasedRaw: inappropriate type (handle does not use file descriptors) +Right "_" +Right "_" +Right "_" ===================================== libraries/base/tests/IO/osHandles002FileDescriptors.hs ===================================== @@ -0,0 +1,28 @@ +import Data.Functor (void) +import Data.ByteString.Char8 (pack) +import System.Posix.Types (Fd (Fd), ByteCount) +import System.Posix.IO.ByteString (fdRead, fdWrite) +import System.IO (stdin, stdout, stderr) +import System.IO.OS + ( + withFileDescriptorReadingBiased, + withFileDescriptorWritingBiased + ) + +main :: IO () +main = withFileDescriptorReadingBiased stdin $ \ stdinFD -> + withFileDescriptorWritingBiased stdout $ \ stdoutFD -> + withFileDescriptorWritingBiased stderr $ \ stderrFD -> + do + regularMsg <- fdRead (Fd stdinFD) inputSizeApproximation + void $ fdWrite (Fd stdoutFD) regularMsg + void $ fdWrite (Fd stderrFD) (pack errorMsg) + where + + inputSizeApproximation :: ByteCount + inputSizeApproximation = 100 + + errorMsg :: String + errorMsg = "And every single door\n\ + \That I've walked through\n\ + \Brings me back, back here again\n" ===================================== libraries/base/tests/IO/osHandles002FileDescriptors.stderr ===================================== @@ -0,0 +1,3 @@ +And every single door +That I've walked through +Brings me back, back here again ===================================== libraries/base/tests/IO/osHandles002FileDescriptors.stdin ===================================== @@ -0,0 +1 @@ +We've got to get in to get out ===================================== libraries/base/tests/IO/osHandles002FileDescriptors.stdout ===================================== @@ -0,0 +1 @@ +We've got to get in to get out ===================================== libraries/base/tests/IO/osHandles002WindowsHandles.hs ===================================== @@ -0,0 +1,49 @@ +import Control.Monad (zipWithM_) +import Data.Functor (void) +import Data.Char (ord) +import Foreign.Marshal.Alloc (allocaBytes) +import Foreign.Storable (pokeElemOff) +import System.IO (stdin, stdout, stderr) +import System.IO.OS + ( + withWindowsHandleReadingBiased, + withWindowsHandleWritingBiased + ) + +main :: IO () +main = withWindowsHandleReadingBiased stdin $ \ windowsStdin -> + withWindowsHandleWritingBiased stdout $ \ windowsStdout -> + withWindowsHandleWritingBiased stderr $ \ windowsStderr -> + do + withBuffer inputSizeApproximation $ \ bufferPtr -> do + inputSize <- win32_ReadFile windowsStdin + bufferPtr + inputSizeApproximation + Nothing + void $ win32_WriteFile windowsStdout + bufferPtr + inputSize + Nothing + withBuffer errorMsgSize $ \ bufferPtr -> do + zipWithM_ (pokeElemOff bufferPtr) + [0 ..] + (map (fromIntegral . ord) errorMsg) + void $ win32_WriteFile windowsStderr + bufferPtr + errorMsgSize + Nothing + where + + withBuffer :: DWORD -> (Ptr Word8 -> IO a) -> IO a + withBuffer = allocaBytes . fromIntegral + + inputSizeApproximation :: DWORD + inputSizeApproximation = 100 + + errorMsg :: String + errorMsg = "And every single door\n\ + \That I've walked through\n\ + \Brings me back, back here again\n" + + errorMsgSize :: DWORD + errorMsgSize = fromIntegral (length errorMsg) ===================================== libraries/base/tests/IO/osHandles002WindowsHandles.stderr ===================================== @@ -0,0 +1,3 @@ +And every single door +That I've walked through +Brings me back, back here again ===================================== libraries/base/tests/IO/osHandles002WindowsHandles.stdin ===================================== @@ -0,0 +1 @@ +We've got to get in to get out ===================================== libraries/base/tests/IO/osHandles002WindowsHandles.stdout ===================================== @@ -0,0 +1 @@ +We've got to get in to get out ===================================== libraries/ghc-internal/ghc-internal.cabal.in ===================================== @@ -328,6 +328,7 @@ Library GHC.Internal.System.Exit GHC.Internal.System.IO GHC.Internal.System.IO.Error + GHC.Internal.System.IO.OS GHC.Internal.System.Mem GHC.Internal.System.Mem.StableName GHC.Internal.System.Posix.Internals ===================================== libraries/ghc-internal/src/GHC/Internal/System/IO/OS.hs ===================================== @@ -0,0 +1,323 @@ +{-# LANGUAGE Safe #-} +{-# LANGUAGE CPP #-} +{-# LANGUAGE RankNTypes #-} + +{-| + This module bridges between Haskell handles and underlying operating-system + features. +-} +module GHC.Internal.System.IO.OS +( + -- * Obtaining file descriptors and Windows handles + withFileDescriptorReadingBiased, + withFileDescriptorWritingBiased, + withWindowsHandleReadingBiased, + withWindowsHandleWritingBiased, + withFileDescriptorReadingBiasedRaw, + withFileDescriptorWritingBiasedRaw, + withWindowsHandleReadingBiasedRaw, + withWindowsHandleWritingBiasedRaw + + -- ** Caveats + -- $with-ref-caveats +) +where + +import GHC.Internal.Control.Monad (return) +import GHC.Internal.Control.Concurrent.MVar (MVar) +import GHC.Internal.Control.Exception (mask) +import GHC.Internal.Data.Function (const, (.), ($)) +import GHC.Internal.Data.Functor (fmap) +#if defined(mingw32_HOST_OS) +import GHC.Internal.Data.Bool (otherwise) +#endif +import GHC.Internal.Data.Maybe (Maybe (Nothing), maybe) +#if defined(mingw32_HOST_OS) +import GHC.Internal.Data.Maybe (Maybe (Just)) +#endif +import GHC.Internal.Data.List ((++)) +import GHC.Internal.Data.String (String) +import GHC.Internal.Data.Typeable (Typeable, cast) +import GHC.Internal.System.IO (IO) +import GHC.Internal.IO.FD (fdFD) +#if defined(mingw32_HOST_OS) +import GHC.Internal.IO.Windows.Handle + ( + NativeHandle, + ConsoleHandle, + IoHandle, + toHANDLE + ) +#endif +import GHC.Internal.IO.Handle.Types + ( + Handle (FileHandle, DuplexHandle), + Handle__ (Handle__, haDevice) + ) +import GHC.Internal.IO.Handle.Internals (withHandle_', flushBuffer) +import GHC.Internal.IO.Exception + ( + IOErrorType (InappropriateType), + IOException (IOError), + ioException + ) +import GHC.Internal.Foreign.Ptr (Ptr) +import GHC.Internal.Foreign.C.Types (CInt) + +-- * Obtaining POSIX file descriptors and Windows handles + +{-| + Executes a user-provided action on an operating-system handle that underlies + a Haskell handle. Before the user-provided action is run, user-defined + preparation based on the handle state that contains the operating-system + handle is performed. While the user-provided action is executed, further + operations on the Haskell handle are blocked to a degree that interference + with this action is prevented. + + See [below](#with-ref-caveats) for caveats regarding this operation. +-} +withOSHandle :: String + -- ^ The name of the overall operation + -> (Handle -> MVar Handle__) + {-^ + Obtaining of the handle state variable that holds the + operating-system handle + -} + -> (forall d. Typeable d => d -> IO a) + -- ^ Conversion of a device into an operating-system handle + -> (Handle__ -> IO ()) + -- ^ The preparation + -> Handle + -- ^ The Haskell handle to use + -> (a -> IO r) + -- ^ The action to execute on the operating-system handle + -> IO r +withOSHandle opName handleStateVar getOSHandle prepare handle act + = mask $ \ withOriginalMaskingState -> + withHandleState $ \ handleState@Handle__ {haDevice = dev} -> do + osHandle <- getOSHandle dev + prepare handleState + withOriginalMaskingState $ act osHandle + where + + withHandleState = withHandle_' opName handle (handleStateVar handle) +{- + The 'withHandle_'' operation, which we use here, already performs masking. + Still, we have to employ 'mask', in order do obtain the operation that + restores the original masking state. The user-provided action should be + executed with this original masking state, as there is no inherent reason to + generally perform it with masking in place. The masking that 'withHandle_'' + performs is only for safely accessing handle state and thus constitutes an + implementation detail; it has nothing to do with the user-provided action. +-} +{- + The order of actions in 'withOSHandle' is such that any exception from + 'getOSHandle' is thrown before the user-defined preparation is performed. +-} + +{-| + Obtains the handle state variable that underlies a handle or specifically + the handle state variable for reading if the handle uses different state + variables for reading and writing. +-} +handleStateVarReadingBiased :: Handle -> MVar Handle__ +handleStateVarReadingBiased (FileHandle _ var) = var +handleStateVarReadingBiased (DuplexHandle _ readingVar _) = readingVar + +{-| + Obtains the handle state variable that underlies a handle or specifically + the handle state variable for writing if the handle uses different state + variables for reading and writing. +-} +handleStateVarWritingBiased :: Handle -> MVar Handle__ +handleStateVarWritingBiased (FileHandle _ var) = var +handleStateVarWritingBiased (DuplexHandle _ _ writingVar) = writingVar + +{-| + Yields the result of another operation if that operation succeeded, and + otherwise throws an exception that signals that the other operation failed + because some Haskell handle does not use an operating-system handle of a + required type. +-} +requiringOSHandleOfType :: String + -- ^ The name of the operating-system handle type + -> Maybe a + {-^ + The result of the other operation if it succeeded + -} + -> IO a +requiringOSHandleOfType osHandleTypeName + = maybe (ioException osHandleOfTypeRequired) return + where + + osHandleOfTypeRequired :: IOException + osHandleOfTypeRequired + = IOError Nothing + InappropriateType + "" + ("handle does not use " ++ osHandleTypeName ++ "s") + Nothing + Nothing + +{-| + Obtains the POSIX file descriptor of a device if the device contains one, + and throws an exception otherwise. +-} +getFileDescriptor :: Typeable d => d -> IO CInt +getFileDescriptor = requiringOSHandleOfType "POSIX file descriptor" . + fmap fdFD . cast + +{-| + Obtains the Windows handle of a device if the device contains one, and + throws an exception otherwise. +-} +getWindowsHandle :: Typeable d => d -> IO (Ptr ()) +getWindowsHandle = requiringOSHandleOfType "Windows handle" . + toMaybeWindowsHandle + where + + toMaybeWindowsHandle :: Typeable d => d -> Maybe (Ptr ()) +#if defined(mingw32_HOST_OS) + toMaybeWindowsHandle dev + | Just nativeHandle <- cast dev :: Maybe (IoHandle NativeHandle) + = Just (toHANDLE nativeHandle) + | Just consoleHandle <- cast dev :: Maybe (IoHandle ConsoleHandle) + = Just (toHANDLE consoleHandle) + | otherwise + = Nothing + {- + This is inspired by the implementation of + 'System.Win32.Types.withHandleToHANDLENative'. + -} +#else + toMaybeWindowsHandle _ = Nothing +#endif + +{-| + Executes a user-provided action on the POSIX file descriptor that underlies + a handle or specifically on the POSIX file descriptor for reading if the + handle uses different file descriptors for reading and writing. The + Haskell-managed buffers related to the file descriptor are flushed before + the user-provided action is run. While this action is executed, further + operations on the handle are blocked to a degree that interference with this + action is prevented. + + If the handle does not use POSIX file descriptors, an exception is thrown. + + See [below](#with-ref-caveats) for caveats regarding this operation. +-} +withFileDescriptorReadingBiased :: Handle -> (CInt -> IO r) -> IO r +withFileDescriptorReadingBiased = withOSHandle "withFileDescriptorReadingBiased" + handleStateVarReadingBiased + getFileDescriptor + flushBuffer + +{-| + Executes a user-provided action on the POSIX file descriptor that underlies + a handle or specifically on the POSIX file descriptor for writing if the + handle uses different file descriptors for reading and writing. The + Haskell-managed buffers related to the file descriptor are flushed before + the user-provided action is run. While this action is executed, further + operations on the handle are blocked to a degree that interference with this + action is prevented. + + If the handle does not use POSIX file descriptors, an exception is thrown. + + See [below](#with-ref-caveats) for caveats regarding this operation. +-} +withFileDescriptorWritingBiased :: Handle -> (CInt -> IO r) -> IO r +withFileDescriptorWritingBiased = withOSHandle "withFileDescriptorWritingBiased" + handleStateVarWritingBiased + getFileDescriptor + flushBuffer + +{-| + Executes a user-provided action on the Windows handle that underlies a + Haskell handle or specifically on the Windows handle for reading if the + Haskell handle uses different Windows handles for reading and writing. The + Haskell-managed buffers related to the Windows handle are flushed before the + user-provided action is run. While this action is executed, further + operations on the Haskell handle are blocked to a degree that interference + with this action is prevented. + + If the Haskell handle does not use Windows handles, an exception is thrown. + + See [below](#with-ref-caveats) for caveats regarding this operation. +-} +withWindowsHandleReadingBiased :: Handle -> (Ptr () -> IO r) -> IO r +withWindowsHandleReadingBiased = withOSHandle "withWindowsHandleReadingBiased" + handleStateVarReadingBiased + getWindowsHandle + flushBuffer + +{-| + Executes a user-provided action on the Windows handle that underlies a + Haskell handle or specifically on the Windows handle for writing if the + Haskell handle uses different Windows handles for reading and writing. The + Haskell-managed buffers related to the Windows handle are flushed before the + user-provided action is run. While this action is executed, further + operations on the Haskell handle are blocked to a degree that interference + with this action is prevented. + + If the Haskell handle does not use Windows handles, an exception is thrown. + + See [below](#with-ref-caveats) for caveats regarding this operation. +-} +withWindowsHandleWritingBiased :: Handle -> (Ptr () -> IO r) -> IO r +withWindowsHandleWritingBiased = withOSHandle "withWindowsHandleWritingBiased" + handleStateVarWritingBiased + getWindowsHandle + flushBuffer + +{-| + Like 'withFileDescriptorReadingBiased' except that Haskell-managed buffers + are not flushed. +-} +withFileDescriptorReadingBiasedRaw :: Handle -> (CInt -> IO r) -> IO r +withFileDescriptorReadingBiasedRaw + = withOSHandle "withFileDescriptorReadingBiasedRaw" + handleStateVarReadingBiased + getFileDescriptor + (const $ return ()) + +{-| + Like 'withFileDescriptorWritingBiased' except that Haskell-managed buffers + are not flushed. +-} +withFileDescriptorWritingBiasedRaw :: Handle -> (CInt -> IO r) -> IO r +withFileDescriptorWritingBiasedRaw + = withOSHandle "withFileDescriptorWritingBiasedRaw" + handleStateVarWritingBiased + getFileDescriptor + (const $ return ()) + +{-| + Like 'withWindowsHandleReadingBiased' except that Haskell-managed buffers + are not flushed. +-} +withWindowsHandleReadingBiasedRaw :: Handle -> (Ptr () -> IO r) -> IO r +withWindowsHandleReadingBiasedRaw + = withOSHandle "withWindowsHandleReadingBiasedRaw" + handleStateVarReadingBiased + getWindowsHandle + (const $ return ()) + +{-| + Like 'withWindowsHandleWritingBiased' except that Haskell-managed buffers + are not flushed. +-} +withWindowsHandleWritingBiasedRaw :: Handle -> (Ptr () -> IO r) -> IO r +withWindowsHandleWritingBiasedRaw + = withOSHandle "withWindowsHandleWritingBiasedRaw" + handleStateVarWritingBiased + getWindowsHandle + (const $ return ()) + +-- ** Caveats + +{-$with-ref-caveats + #with-ref-caveats#This subsection is just a dummy, whose purpose is to serve + as the target of the hyperlinks above. The real documentation of the caveats + is in the /Caveats/ subsection in the @base@ module @System.IO.OS@, which + re-exports the above operations. +-} ===================================== testsuite/tests/interface-stability/base-exports.stdout ===================================== @@ -120,6 +120,7 @@ module Control.Concurrent where isCurrentThreadBound :: GHC.Internal.Types.IO GHC.Internal.Types.Bool isEmptyMVar :: forall a. MVar a -> GHC.Internal.Types.IO GHC.Internal.Types.Bool killThread :: ThreadId -> GHC.Internal.Types.IO () + labelThread :: ThreadId -> GHC.Internal.Base.String -> GHC.Internal.Types.IO () mkWeakMVar :: forall a. MVar a -> GHC.Internal.Types.IO () -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak (MVar a)) mkWeakThreadId :: ThreadId -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak ThreadId) modifyMVar :: forall a b. MVar a -> (a -> GHC.Internal.Types.IO (a, b)) -> GHC.Internal.Types.IO b @@ -10047,6 +10048,17 @@ module System.IO.Error where userError :: GHC.Internal.Base.String -> IOError userErrorType :: IOErrorType +module System.IO.OS where + -- Safety: Safe + withFileDescriptorReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + module System.IO.Unsafe where -- Safety: Unsafe unsafeDupablePerformIO :: forall a. GHC.Internal.Types.IO a -> a ===================================== testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs ===================================== @@ -120,6 +120,7 @@ module Control.Concurrent where isCurrentThreadBound :: GHC.Internal.Types.IO GHC.Internal.Types.Bool isEmptyMVar :: forall a. MVar a -> GHC.Internal.Types.IO GHC.Internal.Types.Bool killThread :: ThreadId -> GHC.Internal.Types.IO () + labelThread :: ThreadId -> GHC.Internal.Base.String -> GHC.Internal.Types.IO () mkWeakMVar :: forall a. MVar a -> GHC.Internal.Types.IO () -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak (MVar a)) mkWeakThreadId :: ThreadId -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak ThreadId) modifyMVar :: forall a b. MVar a -> (a -> GHC.Internal.Types.IO (a, b)) -> GHC.Internal.Types.IO b @@ -10085,6 +10086,17 @@ module System.IO.Error where userError :: GHC.Internal.Base.String -> IOError userErrorType :: IOErrorType +module System.IO.OS where + -- Safety: Safe + withFileDescriptorReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + module System.IO.Unsafe where -- Safety: Unsafe unsafeDupablePerformIO :: forall a. GHC.Internal.Types.IO a -> a ===================================== testsuite/tests/interface-stability/base-exports.stdout-mingw32 ===================================== @@ -120,6 +120,7 @@ module Control.Concurrent where isCurrentThreadBound :: GHC.Internal.Types.IO GHC.Internal.Types.Bool isEmptyMVar :: forall a. MVar a -> GHC.Internal.Types.IO GHC.Internal.Types.Bool killThread :: ThreadId -> GHC.Internal.Types.IO () + labelThread :: ThreadId -> GHC.Internal.Base.String -> GHC.Internal.Types.IO () mkWeakMVar :: forall a. MVar a -> GHC.Internal.Types.IO () -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak (MVar a)) mkWeakThreadId :: ThreadId -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak ThreadId) modifyMVar :: forall a b. MVar a -> (a -> GHC.Internal.Types.IO (a, b)) -> GHC.Internal.Types.IO b @@ -10327,6 +10328,17 @@ module System.IO.Error where userError :: GHC.Internal.Base.String -> IOError userErrorType :: IOErrorType +module System.IO.OS where + -- Safety: Safe + withFileDescriptorReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + module System.IO.Unsafe where -- Safety: Unsafe unsafeDupablePerformIO :: forall a. GHC.Internal.Types.IO a -> a ===================================== testsuite/tests/interface-stability/base-exports.stdout-ws-32 ===================================== @@ -120,6 +120,7 @@ module Control.Concurrent where isCurrentThreadBound :: GHC.Internal.Types.IO GHC.Internal.Types.Bool isEmptyMVar :: forall a. MVar a -> GHC.Internal.Types.IO GHC.Internal.Types.Bool killThread :: ThreadId -> GHC.Internal.Types.IO () + labelThread :: ThreadId -> GHC.Internal.Base.String -> GHC.Internal.Types.IO () mkWeakMVar :: forall a. MVar a -> GHC.Internal.Types.IO () -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak (MVar a)) mkWeakThreadId :: ThreadId -> GHC.Internal.Types.IO (GHC.Internal.Weak.Weak ThreadId) modifyMVar :: forall a b. MVar a -> (a -> GHC.Internal.Types.IO (a, b)) -> GHC.Internal.Types.IO b @@ -10047,6 +10048,17 @@ module System.IO.Error where userError :: GHC.Internal.Base.String -> IOError userErrorType :: IOErrorType +module System.IO.OS where + -- Safety: Safe + withFileDescriptorReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withFileDescriptorWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Foreign.C.Types.CInt -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleReadingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiased :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + withWindowsHandleWritingBiasedRaw :: forall r. GHC.Internal.IO.Handle.Types.Handle -> (GHC.Internal.Ptr.Ptr () -> GHC.Internal.Types.IO r) -> GHC.Internal.Types.IO r + module System.IO.Unsafe where -- Safety: Unsafe unsafeDupablePerformIO :: forall a. 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