FBB::Pipe(3bobcat)

NAME

FBB::Pipe - Defines a system level pipe

SYNOPSIS

#include <bobcat/pipe>
Linking option: -lbobcat

DESCRIPTION

FBB::Pipe objects may be used to construct a pipe. FBB::Pipe objects offer a simple interface to the reading and writing ends of pipes. FBB::Pipe objects are object-wrappers around the pipe(2) system call.

NAMESPACE

FBB
All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.

INHERITS FROM

CONSTRUCTORS

o Pipe():

The default Pipe() constructor constructs a basic pipe, calling pipe(2).

This constructor throws an Errno exception if the default Pipe constructor did not properly complete. The thrown Errno object's which() member shows the system's errno value set by the failing pipe(2) function.

o Pipe(int const *fd):

This constructor expects two file descriptors, which already define a pipe. The copy constructor is available.

Note that when the pipe goes out of scope, no close(2) operation is performed on the pipe's ends. If the pipe should be closed by the desctructor, derive a class from Pipe(3bobcat), whose destructor performs the required closing-operation.

MEMBER FUNCTIONS

o int readFd() const:

Returns the pipe's file descriptor that is used for reading

o void readFrom(int filedescriptor):

Sets up redirection from the internal read filedescriptor to the given filedescriptor: information is read from the FBB::Pipe object when reading from the provided filedescriptor.

o void readFrom(int const *filedescriptors, size_t n):

Sets up redirection from the internal read filedescriptor to the given filedescriptors: information is read from the FBB::Pipe object when reading from any of the n provided filedescriptors (experimental).

o int readOnly():

Closes the writing end of the pipe, returns the reading end's file descriptor.

o void verify() const:

Obsoleted, will be removed in a future Bobcat release.

o int writeFd() const:

Returns the pipe's file descriptor that is used for writing

o void writtenBy(int filedescriptor):

Sets up redirection from the internal write filedescriptor to the given filedescriptor: information is written to the FBB::Pipe object when writing to the provided filedescriptor.

o void writtenBy(int const *filedescriptors, size_t n):

Sets up redirection from the internal write filedescriptor to the given filedescriptors: information is written to the FBB::Pipe object when writing to each of the n provided filedescriptors.

o int writeOnly():

Closes the writing end of the pipe, returns the writing end's file descriptor.

PROTECTED ENUMERATION

The RW protected enumeration has the following elements:

o READ:

The index in d_fd[] (see below) of the element holding the pipe's reading file descriptor;

o WRITE:

The index in d_fd[] (see below) of the element holding the pipe's writing file descriptor

PROTECTED DATA

o int d_fd[2]:

The array holding the pipe's file descriptors. The READ element contains the pipe's reading file descriptor, the WRITE element contains the pipe's writing file descriptor,

EXAMPLE

#include <bobcat/pipe>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <iostream>
#include <string>

using namespace std;
using namespace FBB;

int main()
{

Pipe p; // construct a pipe

cout << "Read file descriptor: " << p.getReadFd() << endl;
cout << "Write file descriptor: " << p.getWriteFd() << endl;

int pid = fork();

if (pid == -1)

return 1;

if (!pid) //child
{

p.readFrom(STDIN_FILENO); // read what goes into the pipe

string s;

getline(cin, s);
cout << "CHILD: Got `" << s << "'" << endl;

getline(cin, s);
cout << "CHILD: Got `" << s << "'" << endl;

return 0;

}

p.writtenBy(STDOUT_FILENO); // write to the pipe via cout

cout << "first line" << endl;
cout << "second line" << endl;

waitpid(pid, 0, 0);

return 0;

}

FILES

bobcat/pipe - defines the class interface

SEE ALSO

bobcat(7), pipe(2)

BUGS

Note that when the pipe goes out of scope, no close(2) operation is performed on the pipe's ends. If the pipe should be closed by the desctructor, derive a class from Pipe(3bobcat), whose destructor performs the required closing-operation.

DISTRIBUTION FILES

o bobcat_2.08.01-x.dsc: detached signature;

o bobcat_2.08.01-x.tar.gz: source archive;

o bobcat_2.08.01-x_i386.changes: change log;

o libbobcat1_2.08.01-x_*.deb: debian package holding the

libraries;

o libbobcat1-dev_2.08.01-x_*.deb: debian package holding the

libraries, headers and manual pages;

o http://sourceforge.net/projects/bobcat: public archive location;

BOBCAT

Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.

COPYRIGHT

This is free software, distributed under the terms of the GNU General Public License (GPL).

AUTHOR

Frank B. Brokken (f.b.brokken@rug.nl).

libbobcat1-dev_2.08.01-x.tar.gz 2005-2010 FBB::Pipe(3bobcat)