FBB::LogBuffer(3bobcat)
log messages stream buffer
(libbobcat-dev_4.08.03-x.tar.gz)
2005-2018
NAME
FBB::LogBuffer - std::streambuf handling log messages
SYNOPSIS
#include <bobcat/logbuffer>
Linking option: -lbobcat
DESCRIPTION
FBB::LogBuffer is a class derived from std::streambuf handling log
messages. The stream to log to, timestamps and log-levels can be configured
both at construction time and beyond. The FBB::LogBuffer may be used to
initialize a std::ostream.
NAMESPACE
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
INHERITS FROM
std::streambuf
ENUMERATION
The enumeration TimeStamps is defined in the namespace FBB to be
used when initializing FBB::LogBuffer objects. It has the following
values:
- NOTIMESTAMPS:
Log-messages will not have timestamps prepended to them.
- TIMESTAMPS:
Log-messages will have timestamps prepended to them.
- UTCTIMESTAMPS:
Log-messages will have timestamps showing the UTC time prepended to
them.
CONSTRUCTORS
- LogBuffer(TimeStamps timestamps = TIMESTAMPS,
bool active = true,
char const *delim = " "):
This constructor constructs an FBB::LogBuffer object writing its
log-messages to std::cerr. If the active parameter is initialized to
false no messages will be logged until the buffer's activity is switched
on (see setActive() below). The parameter delim is inserted
immediately beyond the time stamp. If a delimiter is inappropriate, an empty
string or a 0-pointer may be specified. When stamps == FBB::NOTIMESTAMPS
delim is ignored. A time stamp consists of the month, the day number of the
month and the (local) time of the current message, as usually appearing in
messages in /var/log files. E.g., Aug 5 13:52:23.
- LogBuffer(std::ostream &stream,
TimeStamps timestamps = TIMESTAMPS,
bool active = true,
char const *delim = " "):
This constructor constructs an FBB::LogBuffer object writing its
log-messages to the stream used to initialize its stream parameter. If the
active parameter is initialized to false no messages will be logged
until the buffer's activity is switched on (see setActive() below). The
parameter delim is inserted immediately beyond the time stamp. If a
delimiter is inappropriate, an empty string or a 0-pointer may be
specified. When stamps == FBB::NOTIMESTAMPS delim is ignored. A time stamp
consists of the month, the day number of the month and the (local) time of the
current message, as usually appearing in messages in /var/log files. E.g.,
Aug 5 13:52:23.
Copy and move constructors are not available.
MEMBER FUNCTIONS
All members of std::streambuf are available, as FBB::LogBuffer
inherits from this class.
- int overflow(int c):
This member overrides the std::streambuf member. It is
called by std::ostream objects using OFdStreambuf. It calls
sync(), an then it puts the next available character into the buffer. It
returns the inserted character.
- void setActive(bool active):
The member function (de)activates logging. The argument true
activates logging, the argument false deactivates it.
- void setStream(std::ostream &stream):
This member may be used to switch the stream to log to. It is the
responsibility of the programmer to ensure that the external stream remains
available for as long as log-messages are inserted into it.
- void settimestamp(FBB::TimeStamps timestamps,
char const *delim = " "):
The member function (de)activates time stamp prepending. Use the value
FBB::TIMESTAMPS to prepend time stamps, FBB::NOTIMESTAMPS suppresses
time stamps. A time stamp consists of the month, the day number of the month
and the (local) time of the current message, as usually appearing in messages
in /var/log files. E.g., Aug 5 13:52:23. The parameter delim is
inserted immediately beyond the time stamp. If a delimiter is inappropriate,
an empty string or a 0-pointer may be specified. When stamps ==
FBB::NOTIMESTAMPS delim is ignored.
- void setEmpty(bool empty):
This member may be called to ensure that a timestamp is inserted
before the next insertion. It is called as setEmpty(true) when a newline
character (\n) is inserted, ensuring that another timestamp is prepended
before the next insertion.
- int sync():
This member overrides the std::streambuf member. It writes
the buffer to the device associated with the file descriptor, and returns 0.
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 LogBuffer
can, in accordance with Liskov's Substitution Principle, be used as a
std:streambuf; but it also offers a facility for classes deriving from
LogBuffer. This facility is listed here.
- int pSync():
The contents of the LogBuffer's internal buffer is flushed.
EXAMPLE
#include <iostream>
#include <iomanip>
#include <bobcat/log>
using namespace std;
using namespace FBB;
int main()
{
LogBuffer buffer(cout, FBB::TIMESTAMPS);
ostream log(&buffer);
log << "This message is written to cout" << nl <<
setw(16) << ' ' << "occupying multiple lines\n";
}
FILES
bobcat/logbuffer - defines the class interface
SEE ALSO
bobcat(7), log(3bobcat)
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).