FBB::IFdBuf - Input stream buffer initialized by a file descriptor

       Frank B. Brokken (f.b.brokken@rug.nl).

libbobcat-dev_6.07.01                               2005-2025                               FBB::IFdBuf(3bobcat)

       Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.

       o      https://fbb-git.gitlab.io/bobcat/: gitlab project page;

       Debian Bobcat project files:

       o      libbobcat6: debian package containing the shared library, changelog and copyright note;

       o      libbobcat-dev:  debian package containing the static library, headers, manual pages, and developer
              info;

       The  member  xsgetn(char*dest,std::streamsizen) sets istream::good() to false when fewer bytes than n
       were read using istream::read(). Also see xsgetn’s description.

       Note that by default the provided file descriptors remain open. The complementary  class  ofdbuf(3bobcat)
       by default closes the file descriptor.

       o      IFdBuf():
              This constructor initializes the streambuf, without associating  it  to  a  file  descriptor,  and
              without  using buffering. The member reset can be used subsequently to associate the object with a
              file descriptor and optionally a buffer size. When the object is destroyed  or  if  the  mode-less
              overloaded version of the reset member is called, the file descriptor is not closed.

       o      IFdBuf(Modemode):
              This  constructor  initializes  the  streambuf,  without  associating it to a file descriptor, and
              without using buffering. The member reset can be used subsequently to associate the object with  a
              file  descriptor  and  optionally  a buffer size. When the object is destroyed or if the mode-less
              overloaded version of the member reset is called, the Mode argument determines  whether  the  file
              descriptor will be closed or will remain open.

       o      IFdBuf(intfd,size_tn=1):
              This  constructor initializes the streambuf, associating it to file descriptor fd, and an optional
              unget buffer size (by default having size 1).  When the object is destroyed or  if  the  mode-less
              overloaded version of the member reset is called, the file descriptor is not closed.

       o      IFdBuf(intfd,Modemode,size_tn=1):
              This  constructor initializes the streambuf, associating it to file descriptor fd, and an optional
              unget buffer size (by default having size 1).   When the object is destroyed or if  the  mode-less
              overloaded  version  of  the reset member is called, the Mode argument determines whether the file
              descriptor will be closed or will remain open.

       o      IFdBufSconstructors:
              Use IFdBufS constructors corresponding to  IFdBuf  constructors  to  construct  the  corresponding
              IFdBufS objects.

       Copy and move constructors (and assignment operators) are not available.

       This is free software, distributed under the terms of the GNU General Public License (GPL).

FBB::IFdBuf  objects  may be used as a std::streambuf of std::istream objects to allow extractions from a
       file descriptor.

       FBB::IFdBufS objects operate like FBB::IFdBuf objects but use  FBB::Selector  objects  to  check  whether
       information  on  the  object’s  file  descriptor  is  available  before reading information from the file
       descriptor.

       File descriptors are not defined within the context of C++, but they can be  used  on  operating  systems
       that support the concept. Realize that using file descriptors introduces operating system dependencies.

       The public enumeration Mode defined in the class FBB::IFdStreamBuf has the following values:

       o      CLOSE_FD, indicating that the file descriptor used by the object must be closed;

       o      KEEP_FD (the default) indicating that the file descriptor used by the object must not be closed.

       #include <unistd.h>

       #include <istream>
       #include <iostream>

       #include <bobcat/ifdbuf>

       using namespace std;
       using namespace FBB;

       int main(int argc, char **argv)
       {
                                  // define a streambuf of 20 or argv[1] characters
           IFdBuf buf{ STDIN_FILENO, argc == 1 ? 20 : stoul(argv[1]) };

           istream in{ &buf };

           cout << in.rdbuf();
       }

bobcat/ifdbuf - defines the FBB::IFdBuf class interface
       bobcat/ifdbufs - defines the FBB::IFdBufS class interface

std::streambuf

       All members of std::streambuf are available, as FBB::IFdBuf(S) inherits from this class.

       o      voidclose():
              The  file  descriptor used by the IFdBuf(S) is closed, irrespective of the Mode that was specified
              when the IFdBuf(S) object was constructed. Following close the IFdBuf(S) object can no  longer  be
              used until one of its reset members has been called.

       o      intfd()const:
              The  file  descriptor  used  by the IFdBuf(S) object is returned.  If the OFdBuf is not associated
              with a file descriptor -1 is returned.

       o      voidreset(intfd,size_tn=1):
              The streambuf is (re)initialized, using file descriptor fd, and an optional unget buffer size  (by
              default  having  size  1). When called repeatedly, the Mode specification used whem the object was
              constructed determines whether the file descriptor will be closed or will remain open.

       o      voidreset(intfd,Modemode,size_tn=1):
              The streambuf is (re)initialized, using file descriptor fd, a file  descriptor  closing  parameter
              and  an  optional unget buffer size (by default having size 1). Depending on the Mode argument the
              object’s currently used file descriptor will be closed or will  remain  open  when  the  IFdBuf(S)
              object is destroyed.

       FBB::IFdBuf - Input stream buffer initialized by a file descriptor

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

bobcat(7), ifdstream(3bobcat), ofdbuf(3bobcat), std::streambuf

#include<bobcat/ifdbuf> (when using FBB::IFdBuf#include<bobcat/ifdbufs> (when using FBB::IFdBufS

       Linking option: -lbobcat