Moduleunliftio-0.2.25.1Haskell2010

UnliftIO.Process

Unlifted System.Process.

4 types
20 values

Packageunliftio-0.2.25.1
Exports24
LanguageHaskell2010
LicenceMIT
SourceProcess.hs

Running sub-processes

8 declarations

datadata CreateProcess

Constructors

CreateProcess
- 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 XXX verify what happens with fds in nodejs child processes
- 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 on 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. On JavaScript this also creates a new session.
- delegate_ctlc :: Bool
  Delegate control-C handling. Use this for interactive console processes to let them handle control-C themselves (see below for details).
- detach_console :: Bool
  Use the windows DETACHED_PROCESS flag when creating the process; does nothing on other platforms.
- create_new_console :: Bool
  Use the windows CREATE_NEW_CONSOLE flag when creating the process; does nothing on other platforms.
  Default: False
- new_session :: Bool
  Use posix setsid to start the new process in a new session; starts process in a new session on JavaScript; does nothing on other platforms.
- child_group :: Maybe GroupID
  Use posix setgid to set child process's group id; works for JavaScript when system running nodejs is posix. does nothing on other platforms.
  Default: Nothing
- child_user :: Maybe UserID
  Use posix setuid to set child process's user id; works for JavaScript when system running nodejs is posix. does nothing on other platforms.
  Default: Nothing
- 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

Instances2Eq, Show

Eq CreateProcessDefined in process-1.6.26.1 · System.Process.Common
Show CreateProcessDefined in process-1.6.26.1 · System.Process.Common

datadata 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.
Windows does not have a mechanism for passing multiple arguments. When using RawCommand on Windows, the command line is serialised into a string, with arguments quoted separately. Command line parsing is up individual programs, so the default behaviour may not work for some programs. If you are not getting the desired results, construct the command line yourself and use ShellCommand.

Instances3Eq, Show, IsString

Eq CmdSpecDefined in process-1.6.26.1 · System.Process.Common
Show CmdSpecDefined in process-1.6.26.1 · System.Process.Common
IsString CmdSpecDefined in process-1.6.26.1 · System.Process.Common
construct a ShellCommand from a string literal

datadata 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
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.

Instances2Eq, Show

Eq StdStreamDefined in process-1.6.26.1 · System.Process.Common
Show StdStreamDefined in process-1.6.26.1 · System.Process.Common

datadata 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.

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.

valuecreateProcess

:: MonadIO m
=> CreateProcess
-> m (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

Lifted createProcess.

valuecreateProcess_

:: MonadIO m
=> String
-> CreateProcess
-> m (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

Lifted createProcess_.

valueshell :: String -> CreateProcess

Construct a CreateProcess record for passing to createProcess, representing a command to be passed to the shell.

valueproc :: FilePath -> [String] -> CreateProcess

Construct a CreateProcess record for passing to createProcess, representing a raw command with arguments.

See RawCommand for precise semantics of the specified FilePath.

Simpler functions for common tasks

valuecallProcess :: MonadIO m => FilePath -> [String] -> m ()

Lifted callProcess.

valuecallCommand :: MonadIO m => String -> m ()

Lifted callCommand.

valuespawnProcess :: MonadIO m => FilePath -> [String] -> m ProcessHandle

Lifted spawnProcess.

valuespawnCommand :: MonadIO m => String -> m ProcessHandle

Lifted spawnCommand.

valuereadCreateProcess :: MonadIO m => CreateProcess -> String -> m String

Lifted readCreateProcess.

valuereadProcess :: MonadIO m => FilePath -> [String] -> String -> m String

Lifted readProcess.

valuereadCreateProcessWithExitCode

:: MonadIO m
=> CreateProcess
-> String
-> m (ExitCode, String, String)

Lifted readCreateProcessWithExitCode.

valuereadProcessWithExitCode

:: MonadIO m
=> FilePath
-> [String]
-> String
-> m (ExitCode, String, String)

Lifted readProcessWithExitCode.

valuewithCreateProcess

:: MonadUnliftIO m
=> CreateProcess
-> Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> m a
-> m a

Unlifted withCreateProcess.

Related utilities

valueshowCommandForUser :: FilePath -> [String] -> String

Given a program p and arguments args, showCommandForUser p args returns a string suitable for pasting into /bin/sh (on Unix systems) or CMD.EXE (on Windows).