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Function `std.process.pipeProcess`

Starts a new process, creating pipes to redirect its standard input, output and/or error streams.


						
				ProcessPipes pipeProcess
				(
				

				  scope const(char[])[] args,
				

				  Redirect redirect = cast(Redirect)7,
				

				  const(string[string]) env = cast(const(string[string]))null,
				

				  Config config = cast(Config)0,
				

				  scope const(char)[] workDir = null
				

				) @safe;
				

				

				ProcessPipes pipeProcess
				(
				

				  scope const(char)[] program,
				

				  Redirect redirect = cast(Redirect)7,
				

				  const(string[string]) env = cast(const(string[string]))null,
				

				  Config config = cast(Config)0,
				

				  scope const(char)[] workDir = null
				

				) @safe;

pipeProcess and pipeShell are convenient wrappers around spawnProcess and spawnShell, respectively, and automate the task of redirecting one or more of the child process' standard streams through pipes. Like the functions they wrap, these functions return immediately, leaving the child process to execute in parallel with the invoking process. It is recommended to always call wait on the returned ProcessPipes.pid, as detailed in the documentation for wait.

The args/program/command, env and config parameters are forwarded straight to the underlying spawn functions, and we refer to their documentation for details.

Parameters

Name	Description
args	An array which contains the program name as the zeroth element and any command-line arguments in the following elements. (See `spawnProcess` for details.)
program	The program name, without command-line arguments. (See `spawnProcess` for details.)
command	A shell command which is passed verbatim to the command interpreter. (See `spawnShell` for details.)
redirect	Flags that determine which streams are redirected, and how. See `Redirect` for an overview of available flags.
env	Additional environment variables for the child process. (See `spawnProcess` for details.)
config	Flags that control process creation. See `Config` for an overview of available flags, and note that the `retainStd...` flags have no effect in this function.
workDir	The working directory for the new process. By default the child process inherits the parent's working directory.
shellPath	The path to the shell to use to run the specified program. By default this is `nativeShell`.

Returns

A ProcessPipes object which contains File handles that communicate with the redirected streams of the child process, along with a Pid object that corresponds to the spawned process.

Throws

ProcessException on failure to start the process.
StdioException on failure to redirect any of the streams.

Example

// my_application writes to stdout and might write to stderr
auto pipes = pipeProcess("my_application", Redirect.stdout | Redirect.stderr);
scope(exit) wait(pipes.pid);

// Store lines of output.
string[] output;
foreach (line; pipes.stdout.byLine) output ~= line.idup;

// Store lines of errors.
string[] errors;
foreach (line; pipes.stderr.byLine) errors ~= line.idup;


// sendmail expects to read from stdin
pipes = pipeProcess(["/usr/bin/sendmail", "-t"], Redirect.stdin);
pipes.stdin.writeln("To: you");
pipes.stdin.writeln("From: me");
pipes.stdin.writeln("Subject: dlang");
pipes.stdin.writeln("");
pipes.stdin.writeln(message);

// a single period tells sendmail we are finished
pipes.stdin.writeln(".");

// but at this point sendmail might not see it, we need to flush
pipes.stdin.flush();

// sendmail happens to exit on ".", but some you have to close the file:
pipes.stdin.close();

// otherwise this wait will wait forever
wait(pipes.pid);

Authors

Lars Tandle Kyllingstad, Steven Schveighoffer, Vladimir Panteleev

License

Boost License 1.0.