Spawns a child process and exposes its stdin/stdout/stderr as async handles. More...

#include <pipe.hpp>

Public Member Functions
template<typename TPoller >
	TPipe (TPoller &poller, const std::string &exe, const std::vector< std::string > &args, bool stderrToStdout=false)
	Spawns `exe` with `args` and wires up async I/O handles.

int	Pid () const
	Returns the child's process ID.

void	CloseRead ()
	Closes the read end of the child's stdout pipe.

void	CloseWrite ()
	Closes the write end of the child's stdin pipe, sending EOF to the child.

void	CloseErr ()
	Closes the read end of the child's stderr pipe.

int	Wait ()
	Waits for the child process to exit and returns its exit status.

TFuture< ssize_t >	ReadSome (void *buffer, size_t size)
	Reads up to `size` bytes from the child's stdout.

TFuture< ssize_t >	ReadSomeErr (void *buffer, size_t size)
	Reads up to `size` bytes from the child's stderr.

TFuture< ssize_t >	WriteSome (const void *buffer, size_t size)
	Writes up to `size` bytes to the child's stdin.

Detailed Description

Spawns a child process and exposes its stdin/stdout/stderr as async handles.

Linux/macOS only (#ifndef _WIN32). The constructor forks immediately; the child runs exe with args. The parent side owns three async file handles:

WriteSome → child's stdin
ReadSome → child's stdout
ReadSomeErr → child's stderr (unless stderrToStdout = true)

Call CloseWrite() to send EOF to the child, then Wait() to reap it.

TPipe pipe(poller, "/bin/cat", {});
co_await pipe.WriteSome("hello\n", 6);
pipe.CloseWrite();
 
char buf[64];
ssize_t n = co_await pipe.ReadSome(buf, sizeof(buf));
int exit_code = pipe.Wait();

Constructor & Destructor Documentation

◆ TPipe()

template<typename TPoller >

NNet::TPipe::TPipe	(	TPoller &	poller,
		const std::string &	exe,
		const std::vector< std::string > &	args,
		bool	stderrToStdout = `false`
	)

inline

Spawns exe with args and wires up async I/O handles.

Parameters

poller	Event-loop poller used for async I/O on the pipe fds.
exe	Absolute path to the executable.
args	Arguments passed to the executable (argv[1..]).
stderrToStdout	If `true`, child stderr is redirected into stdout (`ReadSomeErr` becomes unavailable).

Member Function Documentation

◆ ReadSome()

TFuture< ssize_t > NNet::TPipe::ReadSome	(	void *	buffer,
		size_t	size
	)

Reads up to size bytes from the child's stdout.

Returns bytes read (>0), 0 on EOF (child closed stdout), or a negative retry hint on transient errors.

◆ ReadSomeErr()

TFuture< ssize_t > NNet::TPipe::ReadSomeErr	(	void *	buffer,
		size_t	size
	)

Reads up to size bytes from the child's stderr.

Only valid when stderrToStdout = false. Returns bytes read (>0), 0 on EOF, or a negative retry hint.

◆ Wait()

int NNet::TPipe::Wait ( )

Waits for the child process to exit and returns its exit status.

Blocks the calling thread (via waitpid). Call after the child has finished or after sending it a signal.

Returns: The exit status as returned by waitpid (use WEXITSTATUS to extract the code).

◆ WriteSome()

TFuture< ssize_t > NNet::TPipe::WriteSome	(	const void *	buffer,
		size_t	size
	)

Writes up to size bytes to the child's stdin.

Returns bytes written (>0), 0 if the child closed stdin, or a negative retry hint on transient errors.

The documentation for this class was generated from the following files:

coroio/pipe/pipe.hpp
coroio/pipe/pipe.cpp

Public Member Functions