File Wrappers

Overview

Headers

Reference

• Class template basic_file_source
• Class template basic_file_sink
• Class template basic_file

Overview

The class templates basic_file_source, basic_file_sink and basic_file are wrappers for std::basic_filebuf which are CopyConstructible and Assignable. They are useful whenever one wants to access a file without managing the lifetime of a standard file stream or stream buffer. This is because when a stream or stream buffer is added to a filtering_streambuf or filtering_stream it is stored as a reference which must remain valid until that stream or stream buffer is removed from the chain.

The most common specializations are accessible via the typedefs file_source, file_sink, file, wfile_source, wfile_sink and wfile.

Headers

<boost/iostreams/device/file.hpp>

Reference

Class template basic_file_source

Description

CopyConstructible and Assignable wrapper for a std::basic_filebuf opened in read-only mode.

Synopsis

namespace boost { namespace iostreams {

template<typename Ch>
class basic_file_source {
public:
    typedef Ch                      char_type;
    typedef implementation-defined  category;
    basic_file_source( const std::string& path,
                       std::ios_base::openmode mode =
                           std::ios_base::in );
    bool is_open() const;
    ...
};

typedef basic_file_source<char>     file_source;
typedef basic_file_source<wchar_t>  wfile_source;

} } // End namespace boost::iostreams

Template parameters

basic_file_source::basic_file_source

    basic_file_source( const std::string& path,
                       std::ios_base::openmode mode );

Constructs a basic_file_source which wraps a std::basic_filebuf buf opened as follows:

    mode |= std::ios_base::in;
    mode &= ~std::ios_base::out;
    buf.open(path.c_str(), mode);

basic_file_source::is_open

    bool is_open() const;

Returns true if the underlying instance of basic_filebuf was opened successfully.

Class template basic_file_sink

Description

CopyConstructible and Assignable wrapper for a std::basic_filebuf opened in write-only mode.

Synopsis

namespace boost { namespace iostreams {

template<typename Ch>
class basic_file_sink {
public:
    typedef Ch                      char_type;
    typedef implementation-defined  category;
    basic_file_sink( const std::string& path,
                     std::ios_base::openmode mode =
                         std::ios_base::out );
    bool is_open() const;
    ...
};

typedef basic_file_sink<char>     file_sink;
typedef basic_file_sink<wchar_t>  wfile_sink;

} } // End namespace boost::iostreams

Template parameters

basic_file_sink::basic_file_sink

    basic_file_sink( const std::string& path,
                     std::ios_base::openmode mode );

Constructs a basic_file_sink which wraps a std::basic_filebuf buf opened as follows:

    mode |= std::ios_base::out;
    mode &= ~std::ios_base::in;
    buf.open(path.c_str(), mode);

basic_file_sink::is_open

    bool is_open() const;

Returns true if the underlying instance of basic_filebuf was opened successfully.

Class template basic_file

Description

CopyConstructible and Assignable wrapper for a std::basic_filebuf opened in read-write mode by default.

Synopsis

namespace boost { namespace iostreams {

template<typename Ch>
class basic_file {
public:
    typedef Ch                      char_type;
    typedef implementation-defined  category;
    basic_file( const std::string& path,
                std::ios_base::openmode mode =
                    std::ios_base::in | std::ios_base::out );
    bool is_open() const;
    ...
};

typedef basic_file<char>     file;
typedef basic_file<wchar_t>  wfile;

} } // End namespace boost::iostreams

Template parameters

basic_file_::basic_file

    basic_file( const std::string& path,
                std::ios_base::openmode mode );

Constructs a basic_file which wraps a std::basic_filebuf buf opened as follows:

    mode |= std::ios_base::in | std::ios_base::out;
    buf.open(path.c_str(), mode);

basic_file::is_open

    bool is_open() const;

Returns true if the underlying instance of basic_filebuf was opened successfully.

Revised 02 Feb 2008

© Copyright 2008 CodeRage, LLC
© Copyright 2004-2007 Jonathan Turkanis

Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)