Ubuntu Manpage: FBB::Sharedpos - Shared Memory offset controller

Provided by: libbobcat-dev_3.19.01-1ubuntu1_amd64

NAME

       FBB::Sharedpos - Shared Memory offset controller

SYNOPSIS

       #include <bobcat/sharedpos>
       Linking option: -lbobcat

DESCRIPTION

       The  class  SharedPos  is  a  support  class for Bobcat’s shared memory handling classes. It controls the
       shared memory read/write ofset and ensures that shared memory operations never exceed the shared memory’s
       maximum offset.

       The class SharedPos has several public members, but they are primarily useful for other  Shared*  classes
       offered by Bobcat. There is probably little use for a stand-alone SharedPos object.

       In  the  descriptions  of  the class’s member functions offset refers to the read/write offset within the
       available shared memory.

NAMESPACE

       FBB
       All constructors, members, operators and manipulators, mentioned in this man-page,  are  defined  in  the
       namespace FBB.

INHERITS FROM

TYPEDEFS AND ENUMS

CONSTRUCTORS

       Default,  copy  and  move  constructors  are  available. The default constructor does not yet monitor the
       offsets for a shared memory segment. The member reset is used to start monitoring offsets.

OVERLOADED OPERATORS

       o      void operator++():
              The offset is incremented. If this member is called  when  the  offset  is  equal  to  the  shared
              memory’s maximum offset an FBB::Exception is thrown.

       o      void operator+=(size_t len):
              The  offset is incremented by len. If offset + len exceeds the shared memory’s maximum offset then
              the offset is set to the maximum offset and an FBB::Exception is thrown.

       o      std::ostream &operator<<(std::ostream &out, SharedPos const &pos):
              Inserts information about the FBB::SharedPos object into out.

       The copy and move assignment operators are available.

MEMBER FUNCTIONS

o bool atMaxOffset() const:
Returns true if offset equals the maximum offset that can be used for the current shared memory
segment.
The behavior of this member is undefined until setup has been called.

o size_t blockIdx() const:
The index of the shared segment data block in which offset is located is returned.

o size_t blockOffset() const:
The index within the shared segment data block matching offset is returned.

o bool eof() const:
Returns true if offset exceeds the maximum offset of any character ever written to the shared
memory pointed at by sharedData. If eof returns true information may still be written to the
shared memory: writting is possible until the maximum shared memory segment offset has been
reached.
The behavior of this member is undefined until setup has been called.

o std::streamsize eos() const:
The offset just beyond the maximum offset for the current shared segment data block is returned.
The behavior of this member is undefined until setup has been called.

o std::streamsize maxOffset() const:
The maximum possible offset that can be used for the currently monitored shared memory segment is
returned. Zero is returned until setup has been called.

o std::streamsize offset() const:
The offset within the currently monitored shared memory segment is returned. Zero is returned
until setup has been called.

o void setup(SharedSegment *sharedData):
The SharedPos object is reset to monitor the offset of a new FBB::SharedSegment object. The
SharedSegment * must point to a SharedSegment segment (cf. sharedsegment(3bobcat)) that must exist
until the end of the FBB::SharedPos object’s lifetime or until the next reset call. Immediately
after calling reset offset has the value 0.

o std::streamsize showmanyc() const:
The number of characters that can be read from the current shared segment data block is returned.
This member interrogates the number of readable characters in the shared memory segment. This
number may change while this member is being executed. In order to receive a stable return value,
calling functions should have obtained a lock on the shared memory segment before calling this
member. See also the sharedsegment(3bobcat) man-page.
The behavior of this member is undefined until setup has been called.

o std::ios::pos_type seek(std::ios::off_type offset, std::ios::seekdir way = std::ios::beg):
The monitored offset is changed to this member’s offset argument, relative to way. Seeking beyond
eof is OK; -1 is returned when seeking beyond maxOffset or seeking before the shared segment’s
offset 0.

EXAMPLE

       See the sharedstream(3bobcat) man page.

FILES

       bobcat/sharedpos - defines the class interface

BUGS

       None Reported.

DISTRIBUTION FILES

       o      bobcat_3.19.01-x.dsc: detached signature;

       o      bobcat_3.19.01-x.tar.gz: source archive;

       o      bobcat_3.19.01-x_i386.changes: change log;

       o      libbobcat1_3.19.01-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_3.19.01-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).

libbobcat-dev_3.19.01-x.tar.gz                      2005-2013                            FBB::Sharedpos(3bobcat)