process-1.6.10.0: Process libraries
Copyright(c) The University of Glasgow 2004
LicenseBSD-style (see the file libraries/base/LICENSE)
Maintainerlibraries@haskell.org
Stabilityexperimental
Portabilityportable
Safe HaskellTrustworthy
LanguageHaskell2010

System.Process.Internals

Description

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

Synopsis

Documentation

data ProcessHandle__ Source #

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.

On Windows a second wait method can be used to block for event completion. This requires two handles. A process job handle and a events handle to monitor.

Constructors

OpenHandle 

Fields

OpenExtHandle 

Fields

ClosedHandle ExitCode 

data CGid Source #

Instances

Instances details
Bounded CGid 
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Defined in System.Posix.Types

Enum CGid 
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Defined in System.Posix.Types

Eq CGid 
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Defined in System.Posix.Types

Methods

(==) :: CGid -> CGid -> Bool #

(/=) :: CGid -> CGid -> Bool #

Integral CGid 
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Defined in System.Posix.Types

Num CGid 
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Defined in System.Posix.Types

Ord CGid 
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Defined in System.Posix.Types

Methods

compare :: CGid -> CGid -> Ordering #

(<) :: CGid -> CGid -> Bool #

(<=) :: CGid -> CGid -> Bool #

(>) :: CGid -> CGid -> Bool #

(>=) :: CGid -> CGid -> Bool #

max :: CGid -> CGid -> CGid #

min :: CGid -> CGid -> CGid #

Read CGid 
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Defined in System.Posix.Types

Real CGid 
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Defined in System.Posix.Types

Show CGid 
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Storable CGid 
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Bits CGid 
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Defined in System.Posix.Types

FiniteBits CGid 
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Defined in System.Posix.Types

data CreateProcess Source #

Constructors

CreateProcess 

Fields

  • cmdspec :: CmdSpec

    Executable & arguments, or shell command. If cwd is Nothing, relative paths are resolved with respect to the current working directory. If cwd is provided, it is implementation-dependent whether relative paths are resolved with respect to cwd or the current working directory, so absolute paths should be used to ensure portability.

  • 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). This implementation will call close an every fd from 3 to the maximum of open files, which can be slow for high maximum of open files.

  • 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: process-1.2.0.0

  • detach_console :: Bool

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

    Since: process-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: process-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: process-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: process-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: process-1.4.0.0

  • use_process_jobs :: Bool

    On Windows systems this flag indicates that we should wait for the entire process tree to finish before unblocking. On POSIX systems this flag is ignored. See $exec-on-windows for details.

    Default: False

    Since: process-1.5.0.0

Instances

Instances details
Eq CreateProcess # 
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Defined in System.Process.Common

Show CreateProcess # 
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Defined in System.Process.Common

data CmdSpec Source #

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

Instances details
Eq CmdSpec # 
Instance details

Defined in System.Process.Common

Methods

(==) :: CmdSpec -> CmdSpec -> Bool #

(/=) :: CmdSpec -> CmdSpec -> Bool #

Show CmdSpec # 
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Defined in System.Process.Common

IsString CmdSpec #

construct a ShellCommand from a string literal

Since: process-1.2.1.0

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Defined in System.Process.Common

data StdStream Source #

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

Close the stream's file descriptor without passing a Handle. On POSIX systems this may lead to strange behavior in the child process because attempting to read or write after the file has been closed throws an error. This should only be used with child processes that don't use the file descriptor at all. If you wish to ignore the child process's output you should either create a pipe and drain it manually or pass a Handle that writes to /dev/null.

Instances

Instances details
Eq StdStream # 
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Defined in System.Process.Common

Show StdStream # 
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Defined in System.Process.Common

data ProcRetHandles Source #

contains the handles returned by a call to createProcess_Internal

createProcess_ Source #

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.
  • use_process_jobs can be set in CreateProcess since 1.5.0.0 in order to create an I/O completion port to monitor a process tree's progress on Windows.

The function also returns two new handles: * an I/O Completion Port handle on which events will be signaled. * a Job handle which can be used to kill all running processes.

On POSIX platforms these two new handles will always be Nothing

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: process-1.2.1.0

runGenProcess_ Source #

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 Source #

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.

runInteractiveProcess_lock :: MVar () Source #

runInteractiveProcess blocks signals around the fork(). Since blocking/unblocking of signals is a global state operation, we need to ensure mutual exclusion of calls to runInteractiveProcess. This lock is exported so that other libraries which also need to fork() (and also need to make the same global state changes) can protect their changes with the same lock. See https://github.com/haskell/process/pull/154.

Since: process-1.6.6.0

createPipe :: IO (Handle, Handle) Source #

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

Since: process-1.2.1.0

createPipeFd :: IO (FD, FD) Source #

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

Since: process-1.4.2.0

interruptProcessGroupOf Source #

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