| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
GHC.IO.Handle.Lock
Documentation
data FileLockingNotSupported #
Exception thrown by hLock on non-Windows platforms that don't support
flock.
Since: base-4.10.0.0
Constructors
| FileLockingNotSupported |
Instances
| Show FileLockingNotSupported # | Since: base-4.10.0.0 |
Defined in GHC.IO.Handle.Lock Methods showsPrec :: Int -> FileLockingNotSupported -> ShowS # show :: FileLockingNotSupported -> String # showList :: [FileLockingNotSupported] -> ShowS # | |
| Exception FileLockingNotSupported # | |
Defined in GHC.IO.Handle.Lock | |
Indicates a mode in which a file should be locked.
Constructors
| SharedLock | |
| ExclusiveLock |
hLock :: Handle -> LockMode -> IO () #
If a Handle references a file descriptor, attempt to lock contents of the
underlying file in appropriate mode. If the file is already locked in
incompatible mode, this function blocks until the lock is established. The
lock is automatically released upon closing a Handle.
Things to be aware of:
1) This function may block inside a C call. If it does, in order to be able to interrupt it with asynchronous exceptions and/or for other threads to continue working, you MUST use threaded version of the runtime system.
2) The implementation uses LockFileEx on Windows and flock otherwise,
hence all of their caveats also apply here.
3) On non-Windows plaftorms that don't support flock (e.g. Solaris) this
function throws FileLockingNotImplemented. We deliberately choose to not
provide fcntl based locking instead because of its broken semantics.
Since: base-4.10.0.0