darcs-2.18.2: a distributed, interactive, smart revision control system

Copyright | 2008 David Roundy <droundy@darcs.net>
License | GPL
Maintainer | darcs-devel@darcs.net
Stability | experimental
Portability | portable
Safe Haskell | None
Language | Haskell2010

Darcs.Util.Workaround

Description

Synopsis

- setExecutable :: FilePath -> Bool -> IO ()
- getCurrentDirectory :: IO FilePath
- installHandler :: Signal -> Handler -> Maybe SignalSet -> IO Handler
- raiseSignal :: Signal -> IO ()
- data Handler
  - = Default
  - | Ignore
  - | Catch (IO ())
  - | CatchOnce (IO ())
  - | CatchInfo (SignalInfo -> IO ())
  - | CatchInfoOnce (SignalInfo -> IO ())
- type Signal = CInt
- sigINT :: CInt
- sigHUP :: CInt
- sigABRT :: CInt
- sigALRM :: CInt
- sigTERM :: CInt
- sigPIPE :: CInt

# Documentation

setExecutable :: FilePath -> Bool -> IO () #

getCurrentDirectory :: IO FilePath #

Obtain the current working directory as an absolute path.

In a multithreaded program, the current working directory is a global state shared among all threads of the process. Therefore, when performing filesystem operations from multiple threads, it is highly recommended to use absolute rather than relative paths (see: `makeAbsolute`).

Note that `getCurrentDirectory` is not guaranteed to return the same path received by `setCurrentDirectory`. On POSIX systems, the path returned will always be fully dereferenced (not contain any symbolic links). For more information, refer to the documentation of getcwd.

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `isDoesNotExistError` There is no path referring to the working directory. `[EPERM, ENOENT, ESTALE...]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EACCES]`
- `isFullError` Insufficient resources are available to perform the operation.
- `UnsupportedOperation` The operating system has no notion of current working directory.

installHandler #

Arguments

:: Signal |
-> Handler |
-> Maybe SignalSet | other signals to block
-> IO Handler | old handler

`installHandler int handler iset` calls `sigaction` to install an interrupt handler for signal `int`. If `handler` is `Default`, `SIG_DFL` is installed; if `handler` is `Ignore`, `SIG_IGN` is installed; if `handler` is `Catch action`, a handler is installed which will invoke `action` in a new thread when (or shortly after) the signal is received. If `iset` is `Just s`, then the `sa_mask` of the `sigaction` structure is set to `s`; otherwise it is cleared. The previously installed signal handler for `int` is returned

raiseSignal :: Signal -> IO () #

`raiseSignal int` calls `kill` to signal the current process with interrupt signal `int`.

data Handler #

The actions to perform when a signal is received.

Constructors

Default | Sets the disposition of the signal to `SIG_DFL`, which means we want the default action associated with the signal. For example, the default action for `SIGTERM` (and various other signals) is to terminate the process.
Ignore | Set the disposition of the signal to `SIG_IGN`, which means we want to ignore the signal. Ignored signals will not be delivered to the process, and if also blocked will not be added to the pending set for later delivery (if/when unblocked). Some signals (e.g. `SIGSTOP` and `SIGKILL`) cannot be caught or ignored. not yet: | Hold
Catch (IO ()) | signal handler is not reset
CatchOnce (IO ()) | signal handler is automatically reset (via `SA_RESETHAND`)
CatchInfo (SignalInfo -> IO ()) | Since: unix-2.7.0.0
CatchInfoOnce (SignalInfo -> IO ()) | Since: unix-2.7.0.0

type Signal = CInt #

sigINT :: CInt #

Terminal interrupt signal.

sigHUP :: CInt #

Hangup.

sigABRT :: CInt #

Process abort signal.

sigALRM :: CInt #

Alarm clock.

sigTERM :: CInt #

Termination signal.

sigPIPE :: CInt #

Write on a pipe with no one to read it.