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Otherwise, it fails and returns an invalid stream position.</P>

<H3><A NAME="stringbuf::seekpos"><CODE>stringbuf::seekpos</CODE></A></H3>

<PRE>virtual pos_type <B>seekpos</B>(pos_type sp,
    ios_base::openmode mode =
        ios_base::in | ios_base::out);</PRE>

<P>The protected virtual member function endeavors to alter the current
positions for the controlled streams. For an object of class
<CODE>stringbuf</CODE>,
a stream position consists
purely of a stream offset. Offset zero designates the first element
of the controlled sequence. The new position is determined
by <CODE>sp</CODE>.</P>

<P>If
<CODE>mode &amp; ios_base::in</CODE> is nonzero,
the function alters the next position to read in the
<A HREF="streambu.html#input buffer">input buffer</A>.
If <CODE>mode &amp; ios_base::out</CODE> is nonzero,
the function alters the next position to write in the
<A HREF="streambu.html#output buffer">output buffer</A>.
For a stream to be affected, its buffer must exist.
For a positioning operation to succeed, the resulting
stream position must lie within the controlled sequence.
Otherwise (or if neither position is affected) the positioning
operation fails.</P>

<P>If the function succeeds in altering either or both of the stream positions,
it returns the resultant stream position.
Otherwise, it fails and returns an invalid stream position.</P>

<H3><A NAME="stringbuf::str"><CODE>stringbuf::str</CODE></A></H3>

<PRE>string <B>str</B>() const;
void <B>str</B>(const string&amp; newstr);</PRE>

<P>The first member function returns an object of class
<CODE><A HREF="string2.html#string">string</A></CODE>,
whose controlled sequence is a copy of the sequence controlled
by <CODE>*this</CODE>. The sequence copied depends on the stored
<A HREF="#stringbuf mode">stringbuf mode</A> <CODE>mode</CODE>:</P>

<UL>
<LI>If <CODE>mode &amp;
ios_base::<A HREF="ios.html#ios_base::out">out</A></CODE> is nonzero
and an <A HREF="streambu.html#output buffer">output buffer</A> exists,
the sequence is the entire output buffer
(<CODE><A HREF="streambu.html#streambuf::epptr">epptr</A>() -
<A HREF="streambu.html#streambuf::pbase">pbase</A>()</CODE>
elements beginning with <CODE>pbase()</CODE>).</LI>

<LI>Otherwise, if <CODE>mode &amp;
ios_base::<A HREF="ios.html#ios_base::in">in</A></CODE> is nonzero
and an <A HREF="streambu.html#input buffer">input buffer</A> exists,
the sequence is the entire input buffer
(<CODE><A HREF="streambu.html#streambuf::egptr">egptr</A>() -
<A HREF="streambu.html#streambuf::eback">eback</A>()</CODE>
elements beginning with <CODE>eback()</CODE>).</LI>

<LI>Otherwise, the copied sequence is empty.</LI>
</UL>

<P>The second member function deallocates any sequence currently
controlled by <CODE>*this</CODE>. It then
allocates a copy of the sequence controlled
by <CODE>newstr</CODE>. If <CODE>mode &amp; ios_base::in</CODE> is nonzero,
it sets the input buffer to begin reading
at the beginning of the sequence.
If <CODE>mode &amp; ios_base::out</CODE> is nonzero,
it sets the output buffer to begin
writing at the beginning of the sequence.</P>

<H3><A NAME="stringbuf::traits_type"><CODE>stringbuf::traits_type</CODE></A></H3>

<PRE>typedef char_traits <B>traits_type</B>;</PRE>

<P>The type is a synonym for
<CODE><A HREF="string2.html#char_traits">char_traits</A></CODE>.</P>

<H3><A NAME="stringbuf::underflow"><CODE>stringbuf::underflow</CODE></A></H3>

<PRE>virtual int_type <B>underflow</B>();</PRE>

<P>The protected virtual member function endeavors to extract the current
element <CODE>byte</CODE> from the
<A HREF="streambu.html#input buffer">input buffer</A>,
then advance the current stream position, and return the element as
<CODE>traits_type::<A HREF="string2.html#char_traits::to_int_type">to_int_type</A>(byte)</CODE>.
It can do so in only one way:
If a <A HREF="streambu.html#read position">read position</A>
is available, it takes <CODE>byte</CODE> as the element stored
in the read position and advances the next pointer for the input buffer.</P>

<P>If the function cannot succeed, it returns
<CODE>traits_type::<A HREF="string2.html#char_traits::eof">eof</A>()</CODE>. Otherwise,
it returns the current element in the input stream,
converted as described above.</P>

<H2><A NAME="istringstream"><CODE>istringstream</CODE></A></H2>

<PRE>class <B>istringstream</B> : public istream {
public:
    explicit <B><A HREF="#istringstream::istringstream">istringstream</A></B>(ios_base::openmode mode =
        ios_base::in);
    explicit <B><A HREF="#istringstream::istringstream">istringstream</A></B>(const string&amp; str,
        ios_base::openmode mode = ios_base::in);
    stringbuf *<B><A HREF="#istringstream::rdbuf">rdbuf</A></B>() const;
    string <B><A HREF="#istringstream::str">str</A></B>();
    void <B><A HREF="#istringstream::str">str</A></B>(const string&amp; newstr);
    };</PRE>

<P>The class describes an object that controls
extraction of elements and encoded objects from a
<A HREF="streambu.html#stream buffer">stream buffer</A> of class
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.
The object stores an object of class
<CODE>stringbuf</CODE>.</P>

<H3><A NAME="istringstream::allocator_type"><CODE>istringstream::allocator_type</CODE></A></H3>

<PRE>typedef Alloc <B>allocator_type</B>;</PRE>

<P>The type is a synonym for the template parameter <CODE>Alloc</CODE>.</P>

<H3><A NAME="istringstream::istringstream"><CODE>istringstream::istringstream</CODE></A></H3>

<PRE>explicit <B>istringstream</B>(ios_base::openmode mode =
    ios_base::in);
explicit <B>istringstream</B>(const string&amp; str,
    ios_base::openmode mode = ios_base::in);</PRE>

<P>The first constructor initializes the base class by calling
<CODE><A HREF="istream.html#istream::istream">istream</A>(sb)</CODE>,
where <CODE>sb</CODE> is the stored object of class
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.
It also initializes <CODE>sb</CODE> by calling
<CODE><A HREF="#stringbuf::stringbuf">stringbuf</A>(mode | ios_base::in)</CODE>.</P>

<P>The second constructor initializes the base class by calling
<CODE>istream(sb)</CODE>.
It also initializes <CODE>sb</CODE> by calling
<CODE><A HREF="#stringbuf::stringbuf">stringbuf</A>(str,
mode | ios_base::in)</CODE>.</P>

<H3><A NAME="istringstream::rdbuf"><CODE>istringstream::rdbuf</CODE></A></H3>

<PRE>stringbuf *<B>rdbuf</B>() const</PRE>

<P>The member function returns the address of the stored
stream buffer, of type pointer to
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.</P>

<H3><A NAME="istringstream::str"><CODE>istringstream::str</CODE></A></H3>

<PRE>string <B>str</B>() const;
void <B>str</B>(const string&amp; newstr);</PRE>

<P>The first member function returns
<CODE><A HREF="#istringstream::rdbuf">rdbuf</A>()-&gt;
<A HREF="#stringbuf::str">str</A>()</CODE>.
The second member function calls <CODE>rdbuf()-&gt; str(newstr)</CODE>.</P>

<H2><A NAME="ostringstream"><CODE>ostringstream</CODE></A></H2>

<PRE>class <B>ostringstream</B> : public ostream {
public:
    typedef Alloc <B><A HREF="#ostringstream::allocator_type">allocator_type</A></B>;
    explicit <B><A HREF="#ostringstream::ostringstream">ostringstream</A></B>(ios_base::openmode mode =
        ios_base::out);
    explicit <B><A HREF="#ostringstream::ostringstream">ostringstream</A></B>(const string&amp; str,
        ios_base::openmode mode = ios_base::out);
    stringbuf *<B><A HREF="#ostringstream::rdbuf">rdbuf</A></B>() const;
    string <B><A HREF="#ostringstream::str">str</A></B>();
    void <B><A HREF="#ostringstream::str">str</A></B>(const string&amp; newstr);
    };</PRE>

<P>The class describes an object that controls
insertion of elements and encoded objects into a
<A HREF="streambu.html#stream buffer">stream buffer</A> of class
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.
The object stores an object of class
<CODE>stringbuf</CODE>.</P>

<H3><A NAME="ostringstream::allocator_type"><CODE>ostringstream::allocator_type</CODE></A></H3>

<PRE>typedef Alloc <B>allocator_type</B>;</PRE>

<P>The type is a synonym for the template parameter <CODE>Alloc</CODE>.</P>

<H3><A NAME="ostringstream::ostringstream"><CODE>ostringstream::ostringstream</CODE></A></H3>

<PRE>explicit <B>ostringstream</B>(ios_base::openmode mode =
    ios_base::out);
explicit <B>ostringstream</B>(const string&amp; str,
    ios_base::openmode mode = ios_base::out);</PRE>

<P>The first constructor initializes the base class by calling
<CODE><A HREF="ostream.html#ostream::ostream">ostream</A>(sb)</CODE>,
where <CODE>sb</CODE> is the stored object of class
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.
It also initializes <CODE>sb</CODE> by calling
<CODE><A HREF="#stringbuf::stringbuf">stringbuf</A>(mode | ios_base::out)</CODE>.</P>

<P>The second constructor initializes the base class by calling
<CODE>ostream(sb)</CODE>.
It also initializes <CODE>sb</CODE> by calling
<CODE><A HREF="#stringbuf::stringbuf">stringbuf</A>(str,
mode | ios_base::out)</CODE>.</P>

<H3><A NAME="ostringstream::rdbuf"><CODE>ostringstream::rdbuf</CODE></A></H3>

<PRE>stringbuf *<B>rdbuf</B>() const</PRE>

<P>The member function returns the address of the stored
stream buffer, of type pointer to
<CODE><A HREF="#stringbuf">stringbuf</A></CODE>.</P>

<H3><A NAME="ostringstream::str"><CODE>ostringstream::str</CODE></A></H3>

<PRE>string <B>str</B>() const;
void <B>str</B>(const string&amp; newstr);</PRE>

<P>The first member function returns
<CODE><A HREF="#ostringstream::rdbuf">rdbuf</A>()-&gt;
<A HREF="#stringbuf::str">str</A>()</CODE>.
The second member function calls <CODE>rdbuf()-&gt; str(newstr)</CODE>.</P>


<HR>
<P>See also the
<B><A HREF="index.html#Table of Contents">Table of Contents</A></B> and the
<B><A HREF="_index.html">Index</A></B>.</P>

<P><I>
<A HREF="crit_pjp.html">Copyright</A> &#169; 1992-2002
by P.J. Plauger. All rights reserved.</I></P>

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