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- testing 4.08.06-1
- unstable 4.08.06-1
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other sections
FBB::Pipe(3bobcat) | System Level Communication Pipe | FBB::Pipe(3bobcat) |
NAME¶
FBB::Pipe - Defines a system level communication pipeSYNOPSIS¶
#include <bobcat/pipe>DESCRIPTION¶
FBB::Pipe objects may be used to construct a pipe. Pipe objects offer a simple interface to the reading and writing ends of pipes. Pipe objects are object-wrappers around the pipe(2) system call. A Pipe which is created just before a program forks can be used to set up a line of communication between the parent and child process. Information which is written by the child process to its standard output stream can be redirected to the writing end of the pipe (using the writtenBy member). The information appearing at the reading end of the pipe can then be extracted using, e.g., an IFdStream object, initialized with the Pipe’s reading file descriptor, or the reading end of the pipe can be redirected to an existing stream whose file descriptor is known, like cin (which uses the STDIN_FILENO file descriptor). When a Pipe object goes out of scope, no close(2) operation is performed on the pipe’s file descriptors. After setting up the pipe using the Pipe’s member functions and passing the Pipe’s file descriptors to code that uses the Pipe’s descriptors, the Pipe object could in fact safely be destroyed. If the pipe should be closed at destruction time, a class could be derived from Pipe(3bobcat), whose destructor performs the required closing-operation.NAMESPACE¶
FBBINHERITS FROM¶
-CONSTRUCTORS¶
- o
- Pipe():
- This constructor throws an Exception exception if the default Pipe constructor did not properly complete. The thrown Exception object’s which() member shows the system’s errno value set by the failing pipe(2) function.
- o
- Pipe(int const *fd):
MEMBER FUNCTIONS¶
- o
- int readFd() const:
- o
- void readFrom(int filedescriptor):
- o
- void readFrom(int const *filedescriptors, size_t n):
- o
- int readOnly():
- o
- void verify() const:
- o
- int writeFd() const:
- o
- void writtenBy(int filedescriptor):
- o
- void writtenBy(int const *filedescriptors, size_t n):
- o
- int writeOnly():
PROTECTED ENUMERATION¶
The RW protected enumeration has the following elements:- o
- READ:
- o
- WRITE:
PROTECTED DATA¶
- o
- int d_fd[2]:
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; }See also the 2nd example at fork(3bobcat)
FILES¶
bobcat/pipe - defines the class interfaceSEE ALSO¶
bobcat(7), fork(3bobcat), pipe(2), mkfifo(3)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_3.23.01-x.dsc: detached signature;
- o
- bobcat_3.23.01-x.tar.gz: source archive;
- o
- bobcat_3.23.01-x_i386.changes: change log;
- o
- libbobcat1_3.23.01-x_*.deb: debian package holding the libraries;
- o
- libbobcat1-dev_3.23.01-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).2005-2014 | libbobcat-dev_3.23.01-x.tar.gz |