FBB::Mbuf(3bobcat)
Message handler
(libbobcat-dev_6.04.00)
2005-2023
NAME
FBB::Mbuf - std::streambuf handling messages
SYNOPSIS
#include <bobcat/mbuf>
Linking option: -lbobcat
DESCRIPTION
Objects of this class are derived from std::streambuf, and are used to
handle messages in a standardized way. Messages may be prefixed with order
(line) numbers and/or labels.
By default all messages are inserted into the standard output stream, but
other destinations (standard error, a named file, etc.) can easily be
configured.
FBB::Mbuf objects themselves are std::streambuf objects, so they
can be used to construct std::ostream objects. However, they are intended
to be used by mstream(3bobcat) objects, and passing Mbuf objects to
other kind of ostream objects is deprecated and results in undefined
behavior.
NAMESPACE
FBB
All elements mentioned in this man-page, are defined in the namespace
FBB.
INHERITS FROM
std::streambuf
CONSTRUCTORS
- Mbuf():
The default constructor handles messages using the std::streambuf
also used by std::cout. There is no limit to the number of messages that
may be inserted. No message or line numbers are shown, no exception are thrown
when inserting messages.
- explicit Mbuf(std::streambuf *buf,
size_t maxCount = std::numeric_limits<size_t>::max(),
std::string const &tag = "", bool throwing = false):
This constructor uses buf to handle messages. By default (using
the default argument values) there is no limit to the number of messages that
may be inserted. No message or line numbers are shown, no exception are thrown
when inserting messages. Specifying any other value than
std::numeric_limits<size_t>::max() sets the maximum number of messages
that can be inserted to that value. The tag defines the text of the
message label (e.g., Error). When throwing is specified as true an
FBB::Exception exception is thrown after completing a message. The generated
exception holds the id (see below for the member id) of the FBB::Mbuf
object from which the exception was thrown as well as the text FBB::Mbuf.
- explicit Mbuf(std::string const &name, size_t maxCount =
std::numeric_limits<size_t>::max(),
std::string const &tag = "", bool throwing = false):
This constructor creates a std::ofstream from the provided
name parameter that receives the messages handled by the constructed
FBB:Mbuf object. It throws an FBB::Exception exception if the stream
cannot be opened for writing. If a file by that name already exists it is
rewritten. The remaining parameters are identical to those of the previous
two constructors.
Copy and move constructors (and assignment operators) are not available.
MEMBER FUNCTIONS
- size_t count() const:
returns the number of inserted messages (if setCount has been
called: the value set by the last setCount call plus the number of
inserted messages since that call).
- bool lineExcess() const:
returns true after attempting to insert an additional message
after maxCount() number of messages have been inserted.
- std::string const &lineTag() const:
returns the currently used line-tag (by default `Line').
- size_t maxCount() const:
returns the maximum number of messages that can be inserted. If the
returned value equals std::numeric_limits<size_t>::max() then there is no
limit to the number of messages that can be inserted.
- void noLineNr():
calling this member will suppress the display of a line number if it
is called after calling setLineNr (see below) but before a message is
being (or has been) inserted.
- void reset(std::streambuf *buf, size_t maxCount,
std::string const &tag, bool throwing):
messages inserted into FBB::Mbuf objects are handled by
std::streambuf buf. By specifying std::numeric_limits<size_t>::max()
for maxCount there is no limit to the number of messages that may be
handled by this std::streambuf. The tag defines the text of the
message label (e.g., Error or the empty string for no message label). When
throwing is specified as true an FBB::Exception exception is thrown
after completing a message.
- void reset(std::string const &name, size_t maxCount,
std::string const &tag, bool throwing):
messages inserted into FBB::Mbuf objects are handled by a
std::ofstream created using the provided name parameter. It throws an
FBB::Exception exception if the stream cannot be opened for writing. If a
file by that name already exists it is rewritten. The remaining parameters
are identical to those of the previous reset members.
- void reset(FBB::Mbuf const &mbuf):
the current object is reset using the parameters of the mbuf
parameter. Following the reset all of the current object's parameters can
independently be modified from those used by mbuf.
- void setCount(size_t count):
assigns the value count to the object's message counter.
- void setLineNr(size_t lineNr):
specifies the value lineNr as the message's line number when the
next line is displayed (see also noLineNr). This value is not changed
by the FBB::Mbuf object. To display another line number the member will
have to be called again (i.e., the line number is not displayed automatically
again at every new line).
- void setLineTag(std::string const &tag):
specifies the tag prefixing line numbers. By default the line tag
equals `Line'.
- void setMaxCount(size_t maxCount):
defines maxCount as the maximum number of messages that can be
inserted into the FBB::Mbuf object.
- void setTag(std::string const &tag):
specifies the tag prefixing messages. By default the tag is empty. If
not empty the tag is enclosed by square brackets. E.g., specifying the tag
`Error' will prefix messages with [Error].
- std::string const &tag() const:
returns the currently used message tag (by default an empty string).
- bool throws():
returns true when the FBB::Mbuf object will throw an
FBB::Exception exception at the next completed message. The generated
exception holds the id (see earlier for the member id) of the
FBB::Mbuf object from which the exception was thrown as well as the
text FBB::Mbuf.
- void throwing(bool ifTrue):
modifies the behavior of FBB::Mbuf objects at completed
messages. After passing true FBB::Mbuf objects will throw an
FBB::Exception exception at the next completed message, otherwise this
exception is not thrown.
EXAMPLE
See the mstream(3bobcat) example.
FILES
bobcat/mbuf - defines the class interface
SEE ALSO
bobcat(7), exception(3bobcat), mstream(3bobcat)
BUGS
None Reported.
BOBCAT PROJECT FILES
- https://fbb-git.gitlab.io/bobcat/: gitlab project page;
- bobcat_6.04.00-x.dsc: detached signature;
- bobcat_6.04.00-x.tar.gz: source archive;
- bobcat_6.04.00-x_i386.changes: change log;
- libbobcat1_6.04.00-x_*.deb: debian package containing the
libraries;
- libbobcat1-dev_6.04.00-x_*.deb: debian package containing the
libraries, headers and manual pages;
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).