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
Pipe():
The default Pipe() constructor constructs a basic pipe, calling
pipe(2).
The proper completion of this constructor should be checked by calling
the Pipe::verify() member (see below).
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
int readFd() const:
Returns the pipe's file descriptor that is used for reading
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.
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).
int readOnly():
Closes the writing end of the pipe, returns the reading end's file
descriptor.
void verify() const:
This operator throws an Errno exception if the default Pipe
constructor did not properly complete. It should be called before using any
other member of objects constructed by the default Pipe constructor. The
thrown Errno object's which() member shows the system's errno
value set by the failing pipe(2) function.
int writeFd() const:
Returns the pipe's file descriptor that is used for writing
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.
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.
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:
READ:
The index in d_fd[] (see below) of the element holding the pipe's
reading file descriptor;
WRITE:
The index in d_fd[] (see below) of the element holding the pipe's
writing file descriptor
PROTECTED DATA
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
bobcat_2.02.03-x.dsc: detached signature;
bobcat_2.02.03-x.tar.gz: source archive;
bobcat_2.02.03-x_i386.changes: change log;
libbobcat1_2.02.03-x_*.deb: debian package holding the
libraries;
libbobcat1-dev_2.02.03-x_*.deb: debian package holding the
libraries, headers and manual pages;
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).