FBB::IFdBuf(3bobcat)

File Descriptor Input Stream Buffer
(libbobcat-dev_6.02.02)

2005-2022

NAME

SYNOPSIS

DESCRIPTION

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.

NAMESPACE

INHERITS FROM

ENUMERATION

• CLOSE_FD, indicating that the file descriptor used by the object must be closed;
• KEEP_FD (the default) indicating that the file descriptor used by the object must not be closed.

CONSTRUCTORS

• 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.

• IFdBuf(Mode mode):
  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.

• IFdBuf(int fd, size_t n = 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.

• IFdBuf(int fd, Mode mode, size_t n = 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.

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

MEMBER FUNCTIONS

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

• int fd() const:
  The file descriptor used by the IFdBuf object is returned. If the OFdBuf is not associated with a file descriptor -1 is returned.

• void reset(int fd, size_t n = 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.

• void reset(int fd, Mode mode, size_t n = 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 object is destroyed.

EXAMPLE

#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();
}

FILES

SEE ALSO

BUGS

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

BOBCAT PROJECT FILES

• https://fbb-git.gitlab.io/bobcat/: gitlab project page;
• bobcat_6.02.02-x.dsc: detached signature;
• bobcat_6.02.02-x.tar.gz: source archive;
• bobcat_6.02.02-x_i386.changes: change log;
• libbobcat1_6.02.02-x_*.deb: debian package containing the libraries;
• libbobcat1-dev_6.02.02-x_*.deb: debian package containing the libraries, headers and manual pages;

BOBCAT

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AUTHOR