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 <A HREF="basic-filebuf.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="basic-ifstream.html"><IMG SRC="images/bnext.gif" WIDTH=25 HEIGHT=21 ALT="Next file" BORDER=O></A><DIV CLASS="DOCUMENTNAME"><B>Apache C++ Standard Library Reference Guide</B></DIV>
 <H2>basic_fstream</H2>
 <P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-11.html">Input/output</A></P>

 <PRE><HR>                         <IMG SRC="images/inherits.gif"><B><I><A HREF="basic-ostream.html">basic_ostream</A></I></B><IMG SRC="images/inherits.gif">
 <B><I>basic_fstream</I></B><IMG SRC="images/inherits.gif"><B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B>                      <B><I><A HREF="basic-ios.html">basic_ios</A></I></B><IMG SRC="images/inherits.gif"><B><I><A HREF="ios-base.html">ios_base</A></I></B>
                          <IMG SRC="images/inherits.gif"><B><I><A HREF="basic-istream.html">basic_istream</A></I></B><IMG SRC="images/inherits.gif"><HR></PRE>
 <UL>
 <LI><A HREF="#sec1">Local Index</A></LI>
 <LI><A HREF="#sec2">Summary</A></LI>
 <LI><A HREF="#sec3">Synopsis</A></LI>
 <LI><A HREF="#sec4">Description</A></LI>
 <LI><A HREF="#sec5">Interface</A></LI>
 <LI><A HREF="#sec6">Member Types</A></LI>
 <LI><A HREF="#sec7">Nonmember Types</A></LI>
 <LI><A HREF="#sec8">Constructors</A></LI>
 <LI><A HREF="#sec9">Destructors</A></LI>
 <LI><A HREF="#sec10">Member Functions</A></LI>
 <LI><A HREF="#sec11">Example</A></LI>
 <LI><A HREF="#sec12">See Also</A></LI>
 <LI><A HREF="#sec13">Standards Conformance</A></LI>
 </UL>
 <A NAME="sec1"><H3>Local Index</H3></A>
 <H4>Members</H4>
 <UL><TABLE CELLPADDING=3>
 <TR><TD VALIGN=top>
 <A HREF="#idx73">basic_fstream()</A><BR>
 <A HREF="#idx66">char_type</A><BR>
 <A HREF="#idx79">close()</A><BR>
 </TD>
 <TD VALIGN=top><A HREF="#idx80">fd()</A><BR>
 <A HREF="#idx67">int_type</A><BR>
 <A HREF="#idx81">is_open()</A><BR>
 </TD>
 <TD VALIGN=top><A HREF="#idx68">off_type</A><BR>
 <A HREF="#idx82">open()</A><BR>
 <A HREF="#idx69">pos_type</A><BR>
 </TD>
 <TD VALIGN=top><A HREF="#idx86">rdbuf()</A><BR>
 <A HREF="#idx70">traits_type</A><BR>
 <A HREF="#idx78">~basic_fstream()</A><BR>
 </TD></TR>
 </TABLE></UL>
 <H4>Non-Members</H4>
 <UL><TABLE CELLPADDING=3>
 <TR><TD VALIGN=top>
 <A HREF="#idx71">fstream</A><BR>
 </TD>
 <TD VALIGN=top><A HREF="#idx72">wfstream</A><BR>
 </TD>
 <TD VALIGN=top></TD></TR>
 </TABLE></UL>

 <A NAME="sec2"><H3>Summary</H3></A>
 <P>Class that supports reading and writing of named files or devices associated with a file descriptor</P>
 <A NAME="sec3"><H3>Synopsis</H3></A>

 <PRE>#include &lt;fstream&gt;

 namespace std {
   template&lt;class charT, class traits = char_traits&lt;charT&gt; &gt;
   class basic_fstream;
 }
 </PRE>
 <A NAME="sec4"><H3>Description</H3></A>
 <P>The class template <B><I>basic_fstream</I></B> supports reading and writing to named files or other devices associated with a file descriptor. It uses a <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> object to control the associated sequences. It inherits from <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> and can therefore use all the formatted and unformatted input and output functions.</P>
 <A NAME="sec5"><H3>Interface</H3></A>

 <UL><PRE>namespace std {

   template&lt;class charT, class traits = char_traits&lt;charT&gt; &gt;
   class basic_fstream
   : public basic_iostream&lt;charT, traits&gt; {

    public:

     typedef charT  char_type;
     typedef traits traits_type;
     typedef typename traits_type::int_type  int_type;
     typedef typename traits_type::pos_type  pos_type;
     typedef typename traits_type::off_type  off_type;

     basic_fstream();
     explicit basic_fstream(const char*,
              ios_base::openmode = ios_base::in | ios_base::out);

     // extensions:
     explicit basic_fstream(const char*,
                            ios_base::openmode,
                            long);
     explicit basic_fstream(int, char_type* = 0,
                            streamsize = /* default size */);
     explicit basic_fstream(FILE*, char_type* = 0,
                            streamsize = /* default size */);

     virtual ~basic_fstream();

     basic_filebuf&lt;char_type, traits_type&gt; *rdbuf() const;
     bool is_open() const;

     void open(const char*, ios_base::openmode = ios_base::in);

     // extensions:
     int fd() const;
     void open(const char*, ios_base::openmode, long);
     void open(int, char_type* = 0,
               streamsize = /* default size */);
     void open(FILE*, char_type* = 0,
               streamsize = /* default size */);
     void close();

   };
 }
 </PRE></UL>
 <A NAME="sec6"><H3>Member Types</H3></A>

 <A NAME="idx66"></A><PRE><B>char_type</B></PRE>
 <UL>
 <P>The type <SAMP>char_type</SAMP> is a synonym for the template parameter <SAMP>charT</SAMP>.</P>
 </UL>


 <A NAME="idx67"></A><PRE><B>int_type</B></PRE>
 <UL>
 <P>The type <SAMP>int_type</SAMP> is a synonym of type <SAMP>traits_type::in_type</SAMP>.</P>
 </UL>


 <A NAME="idx68"></A><PRE><B>off_type</B></PRE>
 <UL>
 <P>The type <SAMP>off_type</SAMP> is a synonym of type <SAMP>traits_type::off_type</SAMP>.</P>
 </UL>


 <A NAME="idx69"></A><PRE><B>pos_type</B></PRE>
 <UL>
 <P>The type <SAMP>pos_type</SAMP> is a synonym of type <SAMP>traits_type::pos_type</SAMP>.</P>
 </UL>


 <A NAME="idx70"></A><PRE><B>traits_type</B></PRE>
 <UL>
 <P>The type <SAMP>traits_type</SAMP> is a synonym for the template parameter <SAMP>traits</SAMP>.</P>
 </UL>

 <A NAME="sec7"><H3>Nonmember Types</H3></A>

 <A NAME="idx71"></A><PRE><B>fstream</B></PRE>
 <UL>
 <P>The type <SAMP>fstream</SAMP> is an instantiation of class <B><I>basic_fstream</I></B> on type <SAMP>char</SAMP>:</P>
 <P><SAMP>typedef basic_fstream&lt;char&gt; fstream;</SAMP></P>
 </UL>


 <A NAME="idx72"></A><PRE><B>wfstream</B></PRE>
 <UL>
 <P>The type <SAMP>wfstream</SAMP> is an instantiation of class <B><I>basic_fstream</I></B> on type <SAMP>wchar_t:</SAMP></P>
 <P><SAMP>typedef basic_fstream&lt;wchar_t&gt; wfstream;</SAMP></P>
 </UL>

 <A NAME="sec8"><H3>Constructors</H3></A>

 <A NAME="idx73"></A><PRE><B>basic_fstream</B>();</PRE>
 <UL>
 <P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor:</P>
 <P><SAMP>basic_filebuf&lt;char_type, traits_type&gt;(rdbuf())</SAMP></P>
 <P>After construction, a file can be attached to the <B><I>basic_fstream</I></B> object by using the <SAMP>open()</SAMP> member function.</P>
 </UL>


 <A NAME="idx74"></A><PRE><B>basic_fstream</B>(const char* s,
               ios_base::openmode mode =
                 ios_base::in | iosw_base::out);</PRE>
 <UL>
 <P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the constructor: </P>
 <P><SAMP>basic_filebuf&lt;char_type, traits_type&gt;(rdbuf())</SAMP></P>
 <P>The constructor then calls <SAMP>open(s, mode)</SAMP> in order to attach the file, whose name is pointed to by <SAMP>s</SAMP>, to the <B><I>basic_fstream</I></B> object. </P>
 </UL>


 <A NAME="idx75"></A><PRE><B>basic_fstream</B>(const char* s, ios_base::openmode mode,
               long protection);</PRE>
 <UL>
 <P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor: </P>
 <P><SAMP>basic_filebuf&lt;char_type, traits_type&gt;(rdbuf()) </SAMP></P>
 <P>The constructor then calls: </P>
 <P><SAMP>rdbuf()-&gt;open(s, mode, protection)</SAMP></P>
 <P>in order to attach the file, whose name is pointed to by <SAMP>s</SAMP>, to the <B><I>basic_fstream</I></B> object. </P>
 <P>The third argument, <SAMP>protection</SAMP>, holds file permissions. It determines the file read/write/execute permissions under UNIX, but is more limited elsewhere. </P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- The protection argument is not part of the C++ Standard, but is included here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for  a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx76"></A><PRE><B>basic_fstream</B>(int fd, char_type *buf, streamsize n); </PRE>
 <UL>
 <P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor:</P>
 <P><SAMP>basic_filebuf&lt;char_type, traits_type&gt;(rdbuf ())</SAMP></P>
 <P>The constructor then calls: </P>
 <P><SAMP>rdbuf()-&gt;open (fd, buf, n)</SAMP> </P>
 <P>in order to attach the file descriptor <SAMP>fd</SAMP> to the <B><I>basic_fstream</I></B> object. If the function fails, it sets <SAMP>ios_base::failbit</SAMP>. </P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- This function is not part of the C++ Standard, but is included here as an extension in order to manipulate pipes, sockets, or other UNIX devices that can be accessed through file descriptors. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx77"></A><PRE><B>basic_fstream</B>(FILE *fp, char_type* buf, streamsize n); </PRE>
 <UL>
 <P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor: </P>
 <P><SAMP>basic_filebuf&lt;char_type, traits_type&gt;(rdbuf ())</SAMP> </P>
 <P>The constructor then calls:</P>
 <P><SAMP>rdbuf()-&gt;open (fp, buf, n)</SAMP> </P>
 <P>in order to attach the file pointer <SAMP>fp</SAMP> to the <B><I>basic_fstream</I></B> object. If the function fails, it sets <SAMP>ios_base::failbit</SAMP>.</P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>
 <A NAME="sec9"><H3>Destructors</H3></A>

 <A NAME="idx78"></A><PRE>virtual <B>~basic_fstream</B>();</PRE>
 <UL>
 <P>Destroys an object of class <B><I>basic_fstream</I></B>.</P>
 </UL>

 <A NAME="sec10"><H3>Member Functions</H3></A>

 <A NAME="idx79"></A><PRE>void
 <B>close</B>();</PRE>
 <UL>
 <P>Calls <SAMP>rdbuf()-&gt;close()</SAMP>. If this function fails, it calls <SAMP>setstate(failbit)</SAMP>.</P>
 </UL>


 <A NAME="idx80"></A><PRE>int
 <B>fd</B>() const;</PRE>
 <UL>
 <P>Returns the file descriptor associated with the stream.</P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx81"></A><PRE>bool
 <B>is_open</B>() const;</PRE>
 <UL>
 <P>Returns <SAMP>rdbuf()-&gt;is_open()</SAMP>.</P>
 </UL>


 <A NAME="idx82"></A><PRE>void
 <B>open</B>(const char* s,
      ios_base::openmode = ios_base::in | ios_base::out);</PRE>
 <UL>
 <P>Calls <SAMP>rdbuf()-&gt;open(s, mode)</SAMP>. If this function fails to open the file, it calls the <B><I><A HREF="basic-ios.html">basic_ios</A></I></B> member function <SAMP>setstate(failbit)</SAMP>.</P>
 </UL>


 <A NAME="idx83"></A><PRE>void
 <B>open</B>(const char* s,
      ios_base::openmode, long protection);</PRE>
 <UL>
 <P>Calls <SAMP>rdbuf()-&gt;open (s, mode, protection)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
 <P>The third argument, <SAMP>protection</SAMP>, holds file permissions. It determines the file read/write/execute permissions under UNIX. It is more limited under DOS, since files are always readable and do not have special execute permission.</P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- The protection argument does not appear in the C++ Standard C++, but is included here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx84"></A><PRE>void
 <B>open</B>(int fd, char_type *buf = 0,
       streamsize n = /* default size */);</PRE>
 <UL>
 <P>Calls <SAMP>rdbuf()-&gt;open (fd, buf, n)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx85"></A><PRE>void
 <B>open</B>(FILE *fp, char_type *buf = 0,
      streamsize n = /* default size */);</PRE>
 <UL>
 <P>Returns <SAMP>open(fileno (fp), buf, n)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
 <P><SAMP>fileno</SAMP> is a UNIX98 function declared in <SAMP>&lt;cstdio&gt;</SAMP>.</P>
 </UL>

 <BLOCKQUOTE><HR><B>
 NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix&nbsp;B</A> for a complete list of extensions of this implementation.
 </B><HR></BLOCKQUOTE>

 <A NAME="idx86"></A><PRE>basic_filebuf&lt;charT_type,traits_type&gt;*
 <B>rdbuf</B>() const; </PRE>
 <UL>
 <P>Returns a pointer to the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> associated with the stream.</P>
 </UL>

 <A NAME="sec11"><H3>Example</H3></A>

 <UL><PRE>//
 //  fstream.cpp
 //

 #include &lt;fstream&gt;    // for fstream
 #include &lt;iostream&gt;   // for cout, endl
 #include &lt;string&gt;     // for string


 int main ( )
 {
     // create a bi-directional fstream object
     std::fstream inout ("test_fstream.out",
                         std::ios::in | std::ios::out |
                         std::ios::trunc);

     // write out three lines to the file
     inout &lt;&lt; "Dieses ist die Geschichte eines Mannes.\n"
           &lt;&lt; "C'est l'histoire d'un homme.\n"
           &lt;&lt; "This is the story of a man." &lt;&lt; std::endl;

     std::string line;

     // seek back to the beginning of the file
     inout.seekg (0);

     // extract the first line
     std::getline (inout, line);

     // output the first line to standard output
     std::cout &lt;&lt; "\nDeutsch:\n" &lt;&lt; line &lt;&lt; std::endl;

     // obtain current position in file
     std::fstream::pos_type pos = inout.tellg ();

     // extract the second line
     std::getline (inout, line);

     // output the second line to standard output
     std::cout &lt;&lt; "Fran&ccedil;ais:\n" &lt;&lt; line &lt;&lt; std::endl;

     // extract the third line
     std::getline (inout, line);

     // output the third line to standard output
     std::cout &lt;&lt; "English:\n" &lt;&lt; line &lt;&lt; std::endl;

     // move the put sequence before the second line
     inout.seekp (pos);

     // replace the second and third lines
     inout &lt;&lt; "This is the story of a man.\n"
           &lt;&lt; "C'est l'histoire d'un homme.";

     // seek to the beginning of the file
     inout.seekg (0);

     // output the all content of the fstream object to stdout
     std::cout &lt;&lt; "\n" &lt;&lt; inout.rdbuf () &lt;&lt; std::endl;

     return 0;
 }


 Program Output:
 </PRE></UL>
 <UL><PRE>
 Deutsch:
 Dieses ist die Geschichte eines Mannes.
 Francais:
 C'est l'histoire d'un homme.
 English:
 This is the story of a man.

 Dieses ist die Geschichte eines Mannes.
 This is the story of a man.
 C'est l'histoire d'un homme.

 </PRE></UL>
 <A NAME="sec12"><H3>See Also</H3></A>
 <P><B><I><A HREF="char-traits.html">char_traits</A></I></B>, <B><I><A HREF="ios-base.html">ios_base</A></I></B>, <B><I><A HREF="basic-ios.html">basic_ios</A></I></B>, <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B>, <B><I><A HREF="basic-ifstream.html">basic_ifstream</A></I></B>, <B><I><A HREF="basic-ofstream.html">basic_ofstream</A></I></B></P>
 <A NAME="sec13"><H3>Standards Conformance</H3></A>
 <P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.8.1.11</I></P>

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	<H2>basic_fstream</H2>
	<P><B>Library:</B>  <A HREF="2-11.html">Input/output</A></P>

	<PRE><HR> <IMG SRC="images/inherits.gif"><B><I><A HREF="basic-ostream.html">basic_ostream</A></I></B><IMG SRC="images/inherits.gif">
	<B><I>basic_fstream</I></B><IMG SRC="images/inherits.gif"><B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> <B><I><A HREF="basic-ios.html">basic_ios</A></I></B><IMG SRC="images/inherits.gif"><B><I><A HREF="ios-base.html">ios_base</A></I></B>
	<IMG SRC="images/inherits.gif"><B><I><A HREF="basic-istream.html">basic_istream</A></I></B><IMG SRC="images/inherits.gif"><HR></PRE>
	<UL>
	<LI><A HREF="#sec1">Local Index</A></LI>
	<LI><A HREF="#sec2">Summary</A></LI>
	<LI><A HREF="#sec3">Synopsis</A></LI>
	<LI><A HREF="#sec4">Description</A></LI>
	<LI><A HREF="#sec5">Interface</A></LI>
	<LI><A HREF="#sec6">Member Types</A></LI>
	<LI><A HREF="#sec7">Nonmember Types</A></LI>
	<LI><A HREF="#sec8">Constructors</A></LI>
	<LI><A HREF="#sec9">Destructors</A></LI>
	<LI><A HREF="#sec10">Member Functions</A></LI>
	<LI><A HREF="#sec11">Example</A></LI>
	<LI><A HREF="#sec12">See Also</A></LI>
	<LI><A HREF="#sec13">Standards Conformance</A></LI>
	</UL>
	<A NAME="sec1"><H3>Local Index</H3></A>
	<H4>Members</H4>
	<UL><TABLE CELLPADDING=3>
	<TR><TD VALIGN=top>
	<A HREF="#idx73">basic_fstream()</A><BR>
	<A HREF="#idx66">char_type</A><BR>
	<A HREF="#idx79">close()</A><BR>
	</TD>
	<TD VALIGN=top><A HREF="#idx80">fd()</A><BR>
	<A HREF="#idx67">int_type</A><BR>
	<A HREF="#idx81">is_open()</A><BR>
	</TD>
	<TD VALIGN=top><A HREF="#idx68">off_type</A><BR>
	<A HREF="#idx82">open()</A><BR>
	<A HREF="#idx69">pos_type</A><BR>
	</TD>
	<TD VALIGN=top><A HREF="#idx86">rdbuf()</A><BR>
	<A HREF="#idx70">traits_type</A><BR>
	<A HREF="#idx78">~basic_fstream()</A><BR>
	</TD></TR>
	</TABLE></UL>
	<H4>Non-Members</H4>
	<UL><TABLE CELLPADDING=3>
	<TR><TD VALIGN=top>
	<A HREF="#idx71">fstream</A><BR>
	</TD>
	<TD VALIGN=top><A HREF="#idx72">wfstream</A><BR>
	</TD>
	<TD VALIGN=top></TD></TR>
	</TABLE></UL>

	<A NAME="sec2"><H3>Summary</H3></A>
	<P>Class that supports reading and writing of named files or devices associated with a file descriptor</P>
	<A NAME="sec3"><H3>Synopsis</H3></A>

	<PRE>#include <fstream>

	namespace std {
	template<class charT, class traits = char_traits<charT> >
	class basic_fstream;
	}
	</PRE>
	<A NAME="sec4"><H3>Description</H3></A>
	<P>The class template <B><I>basic_fstream</I></B> supports reading and writing to named files or other devices associated with a file descriptor. It uses a <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> object to control the associated sequences. It inherits from <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> and can therefore use all the formatted and unformatted input and output functions.</P>
	<A NAME="sec5"><H3>Interface</H3></A>

	<UL><PRE>namespace std {

	template<class charT, class traits = char_traits<charT> >
	class basic_fstream
	: public basic_iostream<charT, traits> {

	public:

	typedef charT char_type;
	typedef traits traits_type;
	typedef typename traits_type::int_type int_type;
	typedef typename traits_type::pos_type pos_type;
	typedef typename traits_type::off_type off_type;

	basic_fstream();
	explicit basic_fstream(const char*,
	ios_base::openmode = ios_base::in \| ios_base::out);

	// extensions:
	explicit basic_fstream(const char*,
	ios_base::openmode,
	long);
	explicit basic_fstream(int, char_type* = 0,
	streamsize = /* default size */);
	explicit basic_fstream(FILE, char_type = 0,
	streamsize = /* default size */);

	virtual ~basic_fstream();

	basic_filebuf<char_type, traits_type> *rdbuf() const;
	bool is_open() const;

	void open(const char*, ios_base::openmode = ios_base::in);

	// extensions:
	int fd() const;
	void open(const char*, ios_base::openmode, long);
	void open(int, char_type* = 0,
	streamsize = /* default size */);
	void open(FILE, char_type = 0,
	streamsize = /* default size */);
	void close();

	};
	}
	</PRE></UL>
	<A NAME="sec6"><H3>Member Types</H3></A>

	<A NAME="idx66"></A><PRE><B>char_type</B></PRE>
	<UL>
	<P>The type <SAMP>char_type</SAMP> is a synonym for the template parameter <SAMP>charT</SAMP>.</P>
	</UL>


	<A NAME="idx67"></A><PRE><B>int_type</B></PRE>
	<UL>
	<P>The type <SAMP>int_type</SAMP> is a synonym of type <SAMP>traits_type::in_type</SAMP>.</P>
	</UL>


	<A NAME="idx68"></A><PRE><B>off_type</B></PRE>
	<UL>
	<P>The type <SAMP>off_type</SAMP> is a synonym of type <SAMP>traits_type::off_type</SAMP>.</P>
	</UL>


	<A NAME="idx69"></A><PRE><B>pos_type</B></PRE>
	<UL>
	<P>The type <SAMP>pos_type</SAMP> is a synonym of type <SAMP>traits_type::pos_type</SAMP>.</P>
	</UL>


	<A NAME="idx70"></A><PRE><B>traits_type</B></PRE>
	<UL>
	<P>The type <SAMP>traits_type</SAMP> is a synonym for the template parameter <SAMP>traits</SAMP>.</P>
	</UL>

	<A NAME="sec7"><H3>Nonmember Types</H3></A>

	<A NAME="idx71"></A><PRE><B>fstream</B></PRE>
	<UL>
	<P>The type <SAMP>fstream</SAMP> is an instantiation of class <B><I>basic_fstream</I></B> on type <SAMP>char</SAMP>:</P>
	<P><SAMP>typedef basic_fstream<char> fstream;</SAMP></P>
	</UL>


	<A NAME="idx72"></A><PRE><B>wfstream</B></PRE>
	<UL>
	<P>The type <SAMP>wfstream</SAMP> is an instantiation of class <B><I>basic_fstream</I></B> on type <SAMP>wchar_t:</SAMP></P>
	<P><SAMP>typedef basic_fstream<wchar_t> wfstream;</SAMP></P>
	</UL>

	<A NAME="sec8"><H3>Constructors</H3></A>

	<A NAME="idx73"></A><PRE><B>basic_fstream</B>();</PRE>
	<UL>
	<P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor:</P>
	<P><SAMP>basic_filebuf<char_type, traits_type>(rdbuf())</SAMP></P>
	<P>After construction, a file can be attached to the <B><I>basic_fstream</I></B> object by using the <SAMP>open()</SAMP> member function.</P>
	</UL>


	<A NAME="idx74"></A><PRE><B>basic_fstream</B>(const char* s,
	ios_base::openmode mode =
	ios_base::in \| iosw_base::out);</PRE>
	<UL>
	<P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the constructor: </P>
	<P><SAMP>basic_filebuf<char_type, traits_type>(rdbuf())</SAMP></P>
	<P>The constructor then calls <SAMP>open(s, mode)</SAMP> in order to attach the file, whose name is pointed to by <SAMP>s</SAMP>, to the <B><I>basic_fstream</I></B> object. </P>
	</UL>


	<A NAME="idx75"></A><PRE><B>basic_fstream</B>(const char* s, ios_base::openmode mode,
	long protection);</PRE>
	<UL>
	<P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor: </P>
	<P><SAMP>basic_filebuf<char_type, traits_type>(rdbuf()) </SAMP></P>
	<P>The constructor then calls: </P>
	<P><SAMP>rdbuf()->open(s, mode, protection)</SAMP></P>
	<P>in order to attach the file, whose name is pointed to by <SAMP>s</SAMP>, to the <B><I>basic_fstream</I></B> object. </P>
	<P>The third argument, <SAMP>protection</SAMP>, holds file permissions. It determines the file read/write/execute permissions under UNIX, but is more limited elsewhere. </P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- The protection argument is not part of the C++ Standard, but is included here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx76"></A><PRE><B>basic_fstream</B>(int fd, char_type *buf, streamsize n); </PRE>
	<UL>
	<P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor:</P>
	<P><SAMP>basic_filebuf<char_type, traits_type>(rdbuf ())</SAMP></P>
	<P>The constructor then calls: </P>
	<P><SAMP>rdbuf()->open (fd, buf, n)</SAMP> </P>
	<P>in order to attach the file descriptor <SAMP>fd</SAMP> to the <B><I>basic_fstream</I></B> object. If the function fails, it sets <SAMP>ios_base::failbit</SAMP>. </P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- This function is not part of the C++ Standard, but is included here as an extension in order to manipulate pipes, sockets, or other UNIX devices that can be accessed through file descriptors. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx77"></A><PRE><B>basic_fstream</B>(FILE fp, char_type buf, streamsize n); </PRE>
	<UL>
	<P>Constructs an object of class <B><I>basic_fstream</I></B>, initializing the base class <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B> with the associated file buffer. This buffer is initialized by calling the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> constructor: </P>
	<P><SAMP>basic_filebuf<char_type, traits_type>(rdbuf ())</SAMP> </P>
	<P>The constructor then calls:</P>
	<P><SAMP>rdbuf()->open (fp, buf, n)</SAMP> </P>
	<P>in order to attach the file pointer <SAMP>fp</SAMP> to the <B><I>basic_fstream</I></B> object. If the function fails, it sets <SAMP>ios_base::failbit</SAMP>.</P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>
	<A NAME="sec9"><H3>Destructors</H3></A>

	<A NAME="idx78"></A><PRE>virtual <B>~basic_fstream</B>();</PRE>
	<UL>
	<P>Destroys an object of class <B><I>basic_fstream</I></B>.</P>
	</UL>

	<A NAME="sec10"><H3>Member Functions</H3></A>

	<A NAME="idx79"></A><PRE>void
	<B>close</B>();</PRE>
	<UL>
	<P>Calls <SAMP>rdbuf()->close()</SAMP>. If this function fails, it calls <SAMP>setstate(failbit)</SAMP>.</P>
	</UL>


	<A NAME="idx80"></A><PRE>int
	<B>fd</B>() const;</PRE>
	<UL>
	<P>Returns the file descriptor associated with the stream.</P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx81"></A><PRE>bool
	<B>is_open</B>() const;</PRE>
	<UL>
	<P>Returns <SAMP>rdbuf()->is_open()</SAMP>.</P>
	</UL>


	<A NAME="idx82"></A><PRE>void
	<B>open</B>(const char* s,
	ios_base::openmode = ios_base::in \| ios_base::out);</PRE>
	<UL>
	<P>Calls <SAMP>rdbuf()->open(s, mode)</SAMP>. If this function fails to open the file, it calls the <B><I><A HREF="basic-ios.html">basic_ios</A></I></B> member function <SAMP>setstate(failbit)</SAMP>.</P>
	</UL>


	<A NAME="idx83"></A><PRE>void
	<B>open</B>(const char* s,
	ios_base::openmode, long protection);</PRE>
	<UL>
	<P>Calls <SAMP>rdbuf()->open (s, mode, protection)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
	<P>The third argument, <SAMP>protection</SAMP>, holds file permissions. It determines the file read/write/execute permissions under UNIX. It is more limited under DOS, since files are always readable and do not have special execute permission.</P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- The protection argument does not appear in the C++ Standard C++, but is included here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx84"></A><PRE>void
	<B>open</B>(int fd, char_type *buf = 0,
	streamsize n = /* default size */);</PRE>
	<UL>
	<P>Calls <SAMP>rdbuf()->open (fd, buf, n)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx85"></A><PRE>void
	<B>open</B>(FILE fp, char_type buf = 0,
	streamsize n = /* default size */);</PRE>
	<UL>
	<P>Returns <SAMP>open(fileno (fp), buf, n)</SAMP>. If this function fails to open the file, it calls <SAMP>setstate(failbit)</SAMP>. </P>
	<P><SAMP>fileno</SAMP> is a UNIX98 function declared in <SAMP><cstdio></SAMP>.</P>
	</UL>

	<BLOCKQUOTE><HR><B>
	NOTE -- This function is not part of the C++ Standard, but is provided here as a convenience extension. See <A HREF="B.html">Appendix B</A> for a complete list of extensions of this implementation.
	</B><HR></BLOCKQUOTE>

	<A NAME="idx86"></A><PRE>basic_filebuf<charT_type,traits_type>*
	<B>rdbuf</B>() const; </PRE>
	<UL>
	<P>Returns a pointer to the <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B> associated with the stream.</P>
	</UL>

	<A NAME="sec11"><H3>Example</H3></A>

	<UL><PRE>//
	// fstream.cpp
	//

	#include <fstream> // for fstream
	#include <iostream> // for cout, endl
	#include <string> // for string


	int main ( )
	{
	// create a bi-directional fstream object
	std::fstream inout ("test_fstream.out",
	std::ios::in \| std::ios::out \|
	std::ios::trunc);

	// write out three lines to the file
	inout << "Dieses ist die Geschichte eines Mannes.\n"
	<< "C'est l'histoire d'un homme.\n"
	<< "This is the story of a man." << std::endl;

	std::string line;

	// seek back to the beginning of the file
	inout.seekg (0);

	// extract the first line
	std::getline (inout, line);

	// output the first line to standard output
	std::cout << "\nDeutsch:\n" << line << std::endl;

	// obtain current position in file
	std::fstream::pos_type pos = inout.tellg ();

	// extract the second line
	std::getline (inout, line);

	// output the second line to standard output
	std::cout << "Français:\n" << line << std::endl;

	// extract the third line
	std::getline (inout, line);

	// output the third line to standard output
	std::cout << "English:\n" << line << std::endl;

	// move the put sequence before the second line
	inout.seekp (pos);

	// replace the second and third lines
	inout << "This is the story of a man.\n"
	<< "C'est l'histoire d'un homme.";

	// seek to the beginning of the file
	inout.seekg (0);

	// output the all content of the fstream object to stdout
	std::cout << "\n" << inout.rdbuf () << std::endl;

	return 0;
	}


	Program Output:
	</PRE></UL>
	<UL><PRE>
	Deutsch:
	Dieses ist die Geschichte eines Mannes.
	Francais:
	C'est l'histoire d'un homme.
	English:
	This is the story of a man.

	Dieses ist die Geschichte eines Mannes.
	This is the story of a man.
	C'est l'histoire d'un homme.

	</PRE></UL>
	<A NAME="sec12"><H3>See Also</H3></A>
	<P><B><I><A HREF="char-traits.html">char_traits</A></I></B>, <B><I><A HREF="ios-base.html">ios_base</A></I></B>, <B><I><A HREF="basic-ios.html">basic_ios</A></I></B>, <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B>, <B><I><A HREF="basic-ifstream.html">basic_ifstream</A></I></B>, <B><I><A HREF="basic-ofstream.html">basic_ofstream</A></I></B></P>
	<A NAME="sec13"><H3>Standards Conformance</H3></A>
	<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.8.1.11</I></P>

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