System.Process.Internals

Note: This module exports internal implementation details that may change anytime. If you want a more stable API, use System.Process instead.

Documentation

data ProcessHandle

Constructors

ProcessHandle !(MVar ProcessHandle__) !Bool

data ProcessHandle__

A handle to a process, which can be used to wait for termination of the process using waitForProcess.

None of the process-creation functions in this library wait for termination: they all return a ProcessHandle which may be used to wait for the process later.

Constructors

OpenHandle PHANDLE

ClosedHandle ExitCode

type PHANDLE = CPid

closePHANDLE :: PHANDLE -> IO ()

mkProcessHandle :: PHANDLE -> Bool -> IO ProcessHandle

modifyProcessHandle :: ProcessHandle -> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a

withProcessHandle :: ProcessHandle -> (ProcessHandle__ -> IO a) -> IO a

data CreateProcess

Constructors

CreateProcess

Fields

• cmdspec :: CmdSpec

  Executable & arguments, or shell command

• cwd :: Maybe FilePath

  Optional path to the working directory for the new process

• env :: Maybe [(String, String)]

  Optional environment (otherwise inherit from the current process)

• std_in :: StdStream

  How to determine stdin

• std_out :: StdStream

  How to determine stdout

• std_err :: StdStream

  How to determine stderr

• close_fds :: Bool

  Close all file descriptors except stdin, stdout and stderr in the new process (on Windows, only works if std_in, std_out, and std_err are all Inherit)

• create_group :: Bool

  Create a new process group

• delegate_ctlc :: Bool

  Delegate control-C handling. Use this for interactive console processes to let them handle control-C themselves (see below for details).

  On Windows this has no effect.

  Since: 1.2.0.0

• detach_console :: Bool

  Use the windows DETACHED_PROCESS flag when creating the process; does nothing on other platforms.

  Since: 1.3.0.0

• create_new_console :: Bool

  Use the windows CREATE_NEW_CONSOLE flag when creating the process; does nothing on other platforms.

  Default: False

  Since: 1.3.0.0

• new_session :: Bool

  Use posix setsid to start the new process in a new session; does nothing on other platforms.

  Since: 1.3.0.0

• child_group :: Maybe GroupID

  Use posix setgid to set child process's group id; does nothing on other platforms.

  Default: Nothing

  Since: 1.4.0.0

• child_user :: Maybe UserID

  Use posix setuid to set child process's user id; does nothing on other platforms.

  Default: Nothing

  Since: 1.4.0.0

data CmdSpec

Constructors

ShellCommand String

A command line to execute using the shell

RawCommand FilePath [String]

The name of an executable with a list of arguments

The FilePath argument names the executable, and is interpreted according to the platform's standard policy for searching for executables. Specifically:

• on Unix systems the execvp(3) semantics is used, where if the executable filename does not contain a slash (/) then the PATH environment variable is searched for the executable.
• on Windows systems the Win32 CreateProcess semantics is used. Briefly: if the filename does not contain a path, then the directory containing the parent executable is searched, followed by the current directory, then some standard locations, and finally the current PATH. An .exe extension is added if the filename does not already have an extension. For full details see the documentation for the Windows SearchPath API.

Instances

IsString CmdSpec

construct a ShellCommand from a string literal

Since: 1.2.1.0

Methods

fromString :: String -> CmdSpec

data StdStream

Constructors

Inherit

Inherit Handle from parent

UseHandle Handle

Use the supplied Handle

CreatePipe

Create a new pipe. The returned Handle will use the default encoding and newline translation mode (just like Handles created by openFile).

NoStream

No stream handle will be passed

createProcess_

Arguments

:: String

function name (for error messages)

-> CreateProcess

-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

This function is almost identical to createProcess. The only differences are:

• Handles provided via UseHandle are not closed automatically.
• This function takes an extra String argument to be used in creating error messages.

This function has been available from the System.Process.Internals module for some time, and is part of the System.Process module since version 1.2.1.0.

Since: 1.2.1.0

runGenProcess_

Arguments

:: String

function name (for error messages)

-> CreateProcess

-> Maybe CLong

handler for SIGINT

-> Maybe CLong

handler for SIGQUIT

-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

Deprecated: Please do not use this anymore, use the ordinary createProcess. If you need the SIGINT handling, use delegate_ctlc = True (runGenProcess_ is now just an imperfectly emulated stub that probably duplicates or overrides your own signal handling).

fdToHandle :: FD -> IO Handle

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.

startDelegateControlC :: IO ()

endDelegateControlC :: ExitCode -> IO ()

stopDelegateControlC :: IO ()

pPrPr_disableITimers :: IO ()

c_execvpe :: CString -> Ptr CString -> Ptr CString -> IO CInt

ignoreSignal :: CLong

defaultSignal :: CLong

withFilePathException :: FilePath -> IO a -> IO a

withCEnvironment :: [(String, String)] -> (Ptr CString -> IO a) -> IO a

translate :: String -> String

createPipe :: IO (Handle, Handle)

Create a pipe for interprocess communication and return a (readEnd, writeEnd) Handle pair.

Since: 1.2.1.0

createPipeFd :: IO (FD, FD)

Create a pipe for interprocess communication and return a (readEnd, writeEnd) FD pair.

Since: 1.4.2.0

interruptProcessGroupOf

Arguments

:: ProcessHandle

A process in the process group

-> IO ()

Sends an interrupt signal to the process group of the given process.

On Unix systems, it sends the group the SIGINT signal.

On Windows systems, it generates a CTRL_BREAK_EVENT and will only work for processes created using createProcess and setting the create_group flag