rutz::bidir_pipe Class Reference

An exception-safe wrapper around a pipe-fork-exec sequence. More...

#include <rutz/pipe.h>

Collaboration diagram for rutz::bidir_pipe:

Public Member Functions
	bidir_pipe ()
	Default construct; you MUST call init() before using any of the streams!
	bidir_pipe (char const argv)
	Set up a pipe to a child process with the given argv array.
	bidir_pipe (const char *argv0,...)
	Set up a pipe to a child process with the given list of args.
	~bidir_pipe () throw ()
	Destructor cleans up child process and the pipe's file descriptors.
void	block_child_sigint ()
	Request that SIGINT be ignored in the child process.
void	init (char const argv)
	Core code for starting the child process.
void	init (const char *argv0,...)
	Core code for starting the child process.
std::iostream &	in_stream () throw ()
	Get the stream that is receiving input from the child process.
std::iostream &	out_stream () throw ()
	Get the stream that is sending output to the child process.
void	close_in ()
	Close the underlying input stream file descriptor.
void	close_out ()
	Close the underlying output stream file descriptor.
int	exit_status () throw ()
	Wait for child process to complete, return 0 if all is OK, -1 if error.

Detailed Description

An exception-safe wrapper around a pipe-fork-exec sequence.

Definition at line 170 of file pipe.h.

Constructor & Destructor Documentation

rutz::bidir_pipe::bidir_pipe ( )

Default construct; you MUST call init() before using any of the streams!

Definition at line 286 of file pipe.cc.

rutz::bidir_pipe::bidir_pipe ( char *const * argv )

Set up a pipe to a child process with the given argv array.

BE SURE the argv array is NULL-terminated!

Definition at line 297 of file pipe.cc.

References init().

rutz::bidir_pipe::bidir_pipe	(	const char *	argv0,
			...
	)

Set up a pipe to a child process with the given list of args.

BE SURE the variable-length argument list is NULL-terminated!

A private copy will be made of all the arguments, so it is safe to pass const strings here (such as the result of str.c_str() for a std::string object).

Definition at line 308 of file pipe.cc.

References init().

rutz::bidir_pipe::~bidir_pipe ( ) throw ()

Destructor cleans up child process and the pipe's file descriptors.

Definition at line 327 of file pipe.cc.

References close_in(), and close_out().

Member Function Documentation

void rutz::bidir_pipe::block_child_sigint ( )

Request that SIGINT be ignored in the child process.

You must request this BEFORE calling init(); so the proper sequence is:

      rutz::bidir_pipe prog;
      prog.block_child_signals();
      prog.init("progname", "arg1", "arg2", NULL);

This functionality is useful if the parent process is already handling SIGINT specially; if you don't block SIGINT in the child process, then when the user presses Ctrl-C, the following happens: (1) the main parent handles the SIGINT, as desired, but (2) the child process also receives a SIGINT, thus it dies, and (3) the parent process then gets a SIGPIPE and dies itself without getting a chance for a clean exit.

Definition at line 336 of file pipe.cc.

void rutz::bidir_pipe::close_in ( )

Close the underlying input stream file descriptor.

Definition at line 425 of file pipe.cc.

References rutz::stdiostream::close().

Referenced by ~bidir_pipe().

void rutz::bidir_pipe::close_out ( )

Close the underlying output stream file descriptor.

Definition at line 436 of file pipe.cc.

References rutz::stdiostream::close().

Referenced by UcbMpegEncoder::close(), and ~bidir_pipe().

int rutz::bidir_pipe::exit_status ( ) throw ()