FBB::MultiStreambuf(3bobcat)
Writing multiple streams
(libbobcat-dev_4.08.03-x.tar.gz)
2005-2018
NAME
FBB::MultiStreambuf - Selectively writes multiple streams
SYNOPSIS
#include <bobcat/multistreambuf>
Linking option: -lbobcat
DESCRIPTION
The FBB::MultiStreambuf class is a specialization of
std::streambuf. It can be used to write selectively to multiple
std::ostreams. Each std::ostream that is associated with a
MultiStreambuf is given a mode-tag indicating whether the stream
should always be used when information is inserted into the
MultiStreambuf, just once, or not at all. Each of the stream's
mode-tags may be set to any of the defined tag-values.
When the address of a MultiStreambuf is used to initialize a
std::ostream the constructed std::ostream becomes an
output-multiplexer: by inserting information into the std::ostream object,
all std::ostream objects added to its MultiStreambuf buffer which
have an active mode receive that information.
An MultiStreambuf object should be outlived by all active streams
that are associated with it.
MultiStreambuf objects refer to std::ostreams which are passed to it,
and not to their std::streambufs. So it is possible to change these
std::ostream's std::streambufs without reinstalling the std::ostreams
themselves.
No assumptions should be made about the order in which the std::ostream
objects that are associated with the MultiStreambuf objects are
visited when information is inserted.
NAMESPACE
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
INHERITS FROM
std::streambuf
ENUMERATION
In the Mode enumeration the following values are defined:
- OFF:
A std::ostream having this mode will not be used when information
is inserted into a MultiStreambuf
- ON:
A std::ostream having this mode will be used when information
is inserted into a MultiStreambuf
- ONCE:
A std::ostream having this mode will be used once, until the next
flushing operation, when information is inserted into an
MultiStreambuf
- RESET:
A std::ostream having this mode will not be used when information
is inserted into a MultiStreambuf. At a flush operation all ONCE
modes will be set to RESET
- ALL:
This mode is used in combination with the member remove to remove
all std::ostream elements matching a specified std::ostream argument.
TYPES
The following subtypes are defined in the class FBB:MultiStreambuf:
- iterator:
This is a synonym of std::vector<stream>::iterator
- const_iterator:
This is a synonym of std::vector<stream>::const_iterator
NESTED CLASS
The class MultiStreambuf::stream is defined as a nested class of
MultiStreambuf. It offers the following constructor and public
members:
- stream(std::ostream &os, Mode mode = ON):
The constructor stores a std::ostream object, and associates a
Mode value with it.
- void setMode(Mode mode):
This member is used to redefine the stream's Mode value.
- void mode() const:
This member returns the stream's Mode value.
- operator std::ostream &():
This member returns the stream's std::ostream.
CONSTRUCTORS
- MultiStreambuf():
The default constructor creates a MultiStreambuf object which
contains no associated std::ostream objects.
- MultiStreambuf(std::ostream &os, Mode mode = ON):
This constructor creates a MultiStreambuf object which
is immediately associated with the std::ostream specified as its first
argument.
- MultiStreambuf(std::vector<MultiStreambuf::stream> const &osvector):
This constructor creates a MultiStreambuf object which is
immediately associated with all std::ostream objects that are stored in
the MultiStreambuf::stream elements of the specified vector.
The copy constructor is available.
MEMBER FUNCTIONS
All members of std::ostringstream and std::exception are
available, as MultiStreambuf inherits from these classes.
- iterator begin():
This member returns an iterator to the first stream element that
is stored in a MultiStreambuf object.
- const_iterator begin():
This member returns an iterator to the first (unmodifiable) stream
element that is stored in a MultiStreambuf object.
- iterator end():
This member returns an iterator pointing beyond the last stream
element that is stored in a MultiStreambuf object.
- const_iterator end():
This member returns an iterator pointing beyond the last
(unmodifiable) stream element that is stored in a MultiStreambuf
object.
- void insert(std::ostream &os, Mode mode = ON):
This member adds the specified std::ostream using the specified
Mode to the current set of stream objects. Note that if called
multiple times for identical std::ostreams these objects are inserted
multiple times as well.
- void insert(std::vector<stream> const &os):
This member adds all stream objects stored in the os vector to
the current set of stream objects.
- bool remove(std::ostream &os, Mode mode = ONCE):
If os is stored in the MultiStreambuf it is removed, and
true is returned. If mode ALL is specified all os objects that
were stored in the MultiStreambuf object are removed (and true is
returned). If the os object was not stored false is returned. To
determine whether os has been stored in the MultiStreambuf object its
address is compared to the addresses of the std::ostream objects that are
stored inside the MultiStreambuf object: the object(s) having addresses
&os is (are) removed.
- void void setOnce():
This member will reset all the RESET Mode values of the stored
stream objects to ONCE.
- size_t size() const:
The number of streams currently serviced by the
MultiStreambuf object is returned.
PROTECTED MEMBER FUNCTION
The member listed in this section implements the tasks of the comparably
named virtual function in the class's private interface. This separates the
redefinable interface from the user-interface. The class MultiStreamBuf
can, in accordance with Liskov's Substitution Principle, be used as a
std:streambuf; but it also offers a facility for classes deriving from
MultiStreamBuf. This facility is listed here.
- int pSync():
The contents of the MultiStreamBuf's internal buffer is written to
each of the std::ostream objects to which the MultiStreamBuf object
has access.
EXAMPLE
#include <iostream>
#include <fstream>
#include <bobcat/multistreambuf>
using namespace std;
using namespace FBB;
int main()
{
MultiStreambuf msb(cout);
ostream os(&msb);
ofstream out("out");
msb.insert(out, MultiStreambuf::ONCE);
os << "This is on cout and out" << endl;
os << "This is on cout only" << endl;
msb.setOnce();
os << "This is on cout and out" << endl;
os << "This is on cout only" << endl;
return 0;
}
FILES
bobcat/multistreambuf - defines the class interface
SEE ALSO
bobcat(7)
BUGS
None Reported.
DISTRIBUTION FILES
- bobcat_4.08.03-x.dsc: detached signature;
- bobcat_4.08.03-x.tar.gz: source archive;
- bobcat_4.08.03-x_i386.changes: change log;
- libbobcat1_4.08.03-x_*.deb: debian package holding the
libraries;
- libbobcat1-dev_4.08.03-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).
AUTHOR
Frank B. Brokken (f.b.brokken@rug.nl).