redi::basic_pstreambuf< CharT, Traits > Class Template Reference

Class template for stream buffer. More...

#include <pstream.h>

Inheritance diagram for redi::basic_pstreambuf< CharT, Traits >:

List of all members.

Public Types
typedef CharT	char_type
typedef Traits	traits_type
typedef traits_type::int_type	int_type
typedef traits_type::off_type	off_type
typedef traits_type::pos_type	pos_type
typedef int	fd_t
	Type used for file descriptors.
Public Member Functions
	basic_pstreambuf ()
	Default constructor.
	basic_pstreambuf (const std::string &command, pmode mode)
	Constructor that initialises the buffer with command.
	basic_pstreambuf (const std::string &file, const std::vector< std::string > &argv, pmode mode)
	Constructor that initialises the buffer with file and argv..
	~basic_pstreambuf ()
	Destructor.
basic_pstreambuf *	open (const std::string &command, pmode mode)
	Initialise the stream buffer with command.
basic_pstreambuf *	open (const std::string &file, const std::vector< std::string > &argv, pmode mode)
	Initialise the stream buffer with file and argv.
basic_pstreambuf *	close ()
	Close the stream buffer and wait for the process to exit.
basic_pstreambuf *	kill (int signal=SIGTERM)
	Send a signal to the process.
void	peof ()
	Close the pipe connected to the process' stdin.
bool	read_err (bool readerr=true)
	Change active input source.
bool	is_open () const
	Report whether the stream buffer has been initialised.
bool	exited ()
	Report whether the process has exited.
int	status () const
	Return the exit status of the process.
int	error () const
	Return the error number for the most recent failed operation.
Protected Types
enum	buf_read_src { rsrc_out = 0, rsrc_err = 1 }
	Enumerated type to indicate whether stdout or stderr is to be read.
Protected Member Functions
int_type	overflow (int_type c)
	Transfer characters to the pipe when character buffer overflows.
int_type	underflow ()
	Transfer characters from the pipe when the character buffer is empty.
int_type	pbackfail (int_type c=traits_type::eof())
	Make a character available to be returned by the next extraction.
int	sync ()
	Write any buffered characters to the stream.
std::streamsize	xsputn (const char_type *s, std::streamsize n)
bool	write (char_type c)
	Insert a character into the pipe.
bool	read (char_type &c)
	Extract a character from the pipe.
std::streamsize	write (char_type *s, std::streamsize n)
	Insert a sequence of characters into the pipe.
std::streamsize	read (char_type *s, std::streamsize n)
	Extract a sequence of characters from the pipe.
pid_t	fork (pmode mode)
	Initialise pipes and fork process.
int	wait (bool nohang=false)
	Wait for the child process to exit.
fd_t &	wpipe ()
	Return the file descriptor for the output pipe;.
fd_t &	rpipe ()
	Return the file descriptor for the active input pipe.
fd_t &	rpipe (buf_read_src which)
	Return the file descriptor for the specified input pipe.
void	create_buffers (pmode mode)
void	destroy_buffers (pmode mode)
bool	empty_buffer ()
	Writes buffered characters to the process' stdin pipe..
bool	fill_buffer ()
char_type *	rbuffer ()
	Return the active input buffer.
buf_read_src	switch_read_buffer (buf_read_src)

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Detailed Description

template<typename CharT, typename Traits>
class redi::basic_pstreambuf< CharT, Traits >

Class template for stream buffer.

Provides underlying streambuf functionality for the PStreams classes.

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Constructor & Destructor Documentation

template<typename C, typename T> redi::basic_pstreambuf< C, T >::basic_pstreambuf (   )  [inline]

Default constructor. Creates an uninitialised stream buffer.

template<typename C, typename T> redi::basic_pstreambuf< C, T >::basic_pstreambuf (  const std::string &  command, pmode  mode )  [inline]

Constructor that initialises the buffer with command. Initialises the stream buffer by calling open() with the supplied arguments. Parameters: command  a string containing a shell command. mode  the I/O mode to use when opening the pipe. See also: open()

template<typename C, typename T> redi::basic_pstreambuf< C, T >::basic_pstreambuf (  const std::string &  file, const std::vector< std::string > &  argv, pmode  mode )  [inline]

Constructor that initialises the buffer with file and argv.. Initialises the stream buffer by calling open() with the supplied arguments. Parameters: file  a string containing the name of a program to execute. argv  a vector of argument strings passsed to the new program. mode  the I/O mode to use when opening the pipe. See also: open()

template<typename C, typename T> redi::basic_pstreambuf< C, T >::~basic_pstreambuf (   )  [inline]

Destructor. Closes the stream by calling close(). See also: close()

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Member Function Documentation

template<typename C, typename T> basic_pstreambuf< C, T > * redi::basic_pstreambuf< C, T >::close (   )  [inline]

Close the stream buffer and wait for the process to exit. Closes all pipes and waits for the associated process to finish. If an error occurs the error code will be set to one of the possible errors for waitpid(). See your system's documentation for these errors. Returns: this on successful close or NULL if there is no process to close or if an error occurs.

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::empty_buffer (   )  [protected]

Writes buffered characters to the process' stdin pipe.. Returns: true if the buffer was emptied, false otherwise.

template<typename C, typename T> int redi::basic_pstreambuf< C, T >::error (   )  const [inline]

Return the error number for the most recent failed operation. return The error code of the most recently failed operation, or zero.

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::exited (   )  [inline]

Report whether the process has exited. return True if the associated process has exited, false otherwise. see basic_pstreambuf<C,T>::close()

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::fill_buffer (   )  [protected]

Returns: true if the buffer was filled, false otherwise.

template<typename C, typename T> pid_t redi::basic_pstreambuf< C, T >::fork (  pmode  mode  )  [protected]

Initialise pipes and fork process. Creates pipes as specified by mode and calls fork() to create a new process. If the fork is successful the parent process stores the child's PID and the opened pipes and the child process replaces its standard streams with the opened pipes. If an error occurs the error code will be set to one of the possile errors for pipe() or fork(). See your system's documentation for these error codes. Parameters: mode  an OR of pmodes specifying which of the child's standard streams to connect to. Returns: On success the PID of the child is returned in the parent's context and zero is returned in the child's context. On error -1 is returned and the error code is set appropriately.

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::is_open (   )  const [inline]

Report whether the stream buffer has been initialised. Returns: true if a previous call to open() succeeded and close() has not been called successfully, false otherwise. Warning: This function can not be used to determine whether the command used to initialise the buffer was successfully executed or not. If the shell command failed this function will still return true.

template<typename C, typename T> basic_pstreambuf< C, T > * redi::basic_pstreambuf< C, T >::kill (  int  signal = SIGTERM  )  [inline]

Send a signal to the process. Sends the specified signal to the process. A signal can be used to terminate a child process that would not exit otherwise. If an error occurs the error code will be set to one of the possible errors for kill(). See your system's documentation for these errors. Parameters: signal  A signal to send to the child process. Returns: this or NULL if kill() fails.

template<typename C, typename T> basic_pstreambuf< C, T > * redi::basic_pstreambuf< C, T >::open (  const std::string &  file, const std::vector< std::string > &  argv, pmode  mode )  [inline]

Initialise the stream buffer with file and argv. Starts a new process by executing file with the arguments in argv and opens pipes to the process with the specified mode. By convention argv[0] should be the file name of the file being executed. Will duplicate the actions of the shell in searching for an executable file if the specified file name does not contain a slash (/) character. Parameters: file  a string containing the pathname of a program to execute. argv  a vector of argument strings passed to the new program. mode  a bitwise OR of one or more of out, in and err. Returns: NULL if a pipe could not be opened or if the program could not be executed, this otherwise. See also: execvp()

template<typename C, typename T> basic_pstreambuf< C, T > * redi::basic_pstreambuf< C, T >::open (  const std::string &  command, pmode  mode )  [inline]

Initialise the stream buffer with command. Starts a new process by passing command to the shell and opens pipes to the process with the specified mode. There is no way to tell whether the shell command succeeded, this function will always succeed unless resource limits (such as memory usage, or number of processes or open files) are exceeded. Parameters: command  a string containing a shell command. mode  a bitwise OR of one or more of out, in, err. Returns: NULL if the shell could not be started or the pipes could not be opened, this otherwise.

template<typename C, typename T> basic_pstreambuf< C, T >::int_type redi::basic_pstreambuf< C, T >::overflow (  int_type  c  )  [protected]

Transfer characters to the pipe when character buffer overflows. Called when the internal character buffer is not present or is full, to transfer the buffer contents to the pipe. For unbuffered streams this is called for every insertion. Parameters: c  a character to be written to the pipe Returns: traits_type::not_eof(c) if c is equal to traits_type::eof(). Otherwise returns c if c can be written to the pipe, or traits_type::eof() if not.

template<typename C, typename T> basic_pstreambuf< C, T >::int_type redi::basic_pstreambuf< C, T >::pbackfail (  int_type  c = traits_type::eof()  )  [protected]

Make a character available to be returned by the next extraction. Attempts to make c available as the next character to be read by sgetc(). Parameters: c  a character to make available for extraction. Returns: c if the character can be made available, traits_type::eof() otherwise.

template<typename C, typename T> void redi::basic_pstreambuf< C, T >::peof (   )  [inline]

Close the pipe connected to the process' stdin. closes the output pipe, causing the child process to receive the End Of File indicator on subsequent reads from its stdin stream. Returns: peof() returns no value.

template<typename C, typename T> basic_pstreambuf< C, T >::char_type * redi::basic_pstreambuf< C, T >::rbuffer (   )  [inline, protected]

Return the active input buffer. Returns: a pointer to the start of the active input buffer area.

template<typename C, typename T> std::streamsize redi::basic_pstreambuf< C, T >::read (  char_type *  s, std::streamsize  n )  [inline, protected]

Extract a sequence of characters from the pipe. Reads up to n characters from the pipe to the buffer s. This currently only works for fixed width character encodings where each character uses sizeof(char_type) bytes. Parameters: s  character buffer. n  buffer length. Returns: the number of characters read.

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::read (  char_type &  c  )  [inline, protected]

Extract a character from the pipe. Attempts to extract a character from the pipe and store it in c. Used by underflow(). Parameters: c  a reference to hold the extracted character. Returns: true if a character could be extracted, false otherwise. See also: read(char_type* s, std::streamsize n)

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::read_err (  bool  readerr = true  )  [inline]

Change active input source. Toggle the stream used for reading. If readerr is true then the process' stderr output will be used for subsequent extractions, if readerr is false the the process' stdout will be used. Parameters: readerr  true to read stderr, false to read stdout. Returns: true if the requested stream is open and will be used for subsequent extractions, false otherwise.

template<typename C, typename T> basic_pstreambuf< C, T >::fd_t & redi::basic_pstreambuf< C, T >::rpipe (  buf_read_src  which  )  [inline, protected]

Return the file descriptor for the specified input pipe. Returns: a reference to the specified input file descriptor

template<typename C, typename T> basic_pstreambuf< C, T >::fd_t & redi::basic_pstreambuf< C, T >::rpipe (   )  [inline, protected]

Return the file descriptor for the active input pipe. Returns: a reference to the active input file descriptor

template<typename C, typename T> int redi::basic_pstreambuf< C, T >::status (   )  const [inline]

Return the exit status of the process. return The exit status of the child process, or -1 if close() has not yet been called to wait for the child to exit. see basic_pstreambuf<C,T>::close()

template<typename C, typename T> basic_pstreambuf< C, T >::int_type redi::basic_pstreambuf< C, T >::underflow (   )  [protected]

Transfer characters from the pipe when the character buffer is empty. Called when the internal character buffer is is empty, to re-fill it from the pipe. Returns: The first available character in the buffer, or traits_type::eof() in case of failure. See also: uflow()

template<typename C, typename T> int redi::basic_pstreambuf< C, T >::wait (  bool  nohang = false  )  [inline, protected]

Wait for the child process to exit. Suspends execution and waits for the associated process to exit, or until a signal is delivered whose action is to terminate the current process or to call a signal handling function. If the process has already exited wait() returns immediately. Parameters: nohang  true to return immediately if the process has not exited. Returns: 1 if the process has exited, 0 if nohang is true and the process has not exited yet, -1 if an error occurs, in which case the error can be found using error().

template<typename C, typename T> basic_pstreambuf< C, T >::fd_t & redi::basic_pstreambuf< C, T >::wpipe (   )  [inline, protected]

Return the file descriptor for the output pipe;. Returns: a reference to the output file descriptor

template<typename C, typename T> std::streamsize redi::basic_pstreambuf< C, T >::write (  char_type *  s, std::streamsize  n )  [inline, protected]

Insert a sequence of characters into the pipe. Writes up to n characters to the pipe from the buffer s. This currently only works for fixed width character encodings where each character uses sizeof(char_type) bytes. Parameters: s  character buffer. n  buffer length. Returns: the number of characters written.

template<typename C, typename T> bool redi::basic_pstreambuf< C, T >::write (  char_type  c  )  [inline, protected]

Insert a character into the pipe. Attempts to insert c into the pipe. Used by overflow(). Parameters: c  a character to insert. Returns: true if the character could be inserted, false otherwise. See also: write(char_type* s, std::streamsize n)

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

• pstream.h

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