mirror of
https://github.com/boostorg/smart_ptr.git
synced 2025-07-30 20:57:21 +02:00
Added a default constructor to shared_count and shared_ptr for incomplete types (void).
[SVN r12815]
This commit is contained in:
Peter Dimov
@ -186,6 +186,10 @@ private:
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public:
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shared_count(): pi_(new counted_base(1, 1))
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{
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}
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template<class P, class D> shared_count(P p, D d): pi_(0)
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{
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try
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@ -221,7 +225,7 @@ public:
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pi_->add_ref();
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}
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explicit shared_count(weak_count const & r); // throws bad_weak_to_shared_cast when r.use_count() == 0
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explicit shared_count(weak_count const & r); // throws use_count_is_zero when r.use_count() == 0
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shared_count & operator= (shared_count const & r) // nothrow
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{
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@ -81,7 +81,11 @@ public:
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typedef T element_type;
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explicit shared_ptr(T * p = 0): px(p), pn(p, deleter())
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shared_ptr(): px(0), pn()
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{
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}
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explicit shared_ptr(T * p): px(p), pn(p, deleter()) // requires complete type
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{
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}
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@ -157,9 +161,14 @@ public:
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#endif
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void reset(T * p = 0)
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void reset()
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{
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BOOST_ASSERT(p == 0 || p != px);
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this_type().swap(*this);
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}
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void reset(T * p) // requires complete type
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{
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BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors
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this_type(p).swap(*this);
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}
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@ -40,6 +40,8 @@
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<h2><a name="Synopsis">Synopsis</a></h2>
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<pre>namespace boost {
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class use_count_is_zero: public std::exception;
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template<typename T> class <A href="weak_ptr.htm" >weak_ptr</A>;
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template<typename T> class shared_ptr {
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@ -47,20 +49,22 @@
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public:
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typedef T <A href="#element_type" >element_type</A>;
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explicit <A href="#constructors" >shared_ptr</A>(T * p = 0);
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<A href="#constructors" >shared_ptr</A> ();
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explicit <A href="#constructors" >shared_ptr</A> (T * p); // requires complete type
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template<typename D> <A href="#constructors" >shared_ptr</A>(T * p, D d);
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<A href="#destructor" >~shared_ptr</A>(); // never throws
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<A href="#constructors" >shared_ptr</A>(shared_ptr const & r); // never throws
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template<typename Y> <A href="#constructors" >shared_ptr</A>(shared_ptr<Y> const & r); // never throws
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<A href="#constructors" >shared_ptr</A>(<A href="weak_ptr.htm" >weak_ptr</A> const & r);
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explicit <A href="#constructors" >shared_ptr</A>(<A href="weak_ptr.htm" >weak_ptr</A> const & r);
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template<typename Y> <A href="#constructors" >shared_ptr</A>(std::auto_ptr<Y> & r);
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shared_ptr & <A href="#assignment" >operator=</A>(shared_ptr const & r); // never throws
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template<typename Y> shared_ptr & <A href="#assignment" >operator=</A>(shared_ptr<Y> const & r); // never throws
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template<typename Y> shared_ptr & <A href="#assignment" >operator=</A>(std::auto_ptr<Y> & r);
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void <A href="#reset" >reset</A>(T * p = 0);
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void <A href="#reset" >reset</A> ();
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void <A href="#reset" >reset</A> (T * p); // requires complete type
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template<typename D> void <A href="#reset" >reset</A>(T * p, D d);
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T & <A href="#indirection" >operator*</A>() const; // never throws
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@ -99,7 +103,18 @@
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<p>Provides the type of the template parameter T.</p>
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</blockquote>
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<h3><a name="constructors">constructors</a></h3>
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<pre>explicit shared_ptr(T * p = 0);</pre>
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<pre>shared_ptr();</pre>
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<blockquote>
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<p><b>Effects:</b> Constructs a <b>shared_ptr</b>.</p>
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<p><b>Postconditions:</b> <A href="#use_count">use count</A> is 1; the stored
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pointer is 0.</p>
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<p><b>Throws:</b> <b>std::bad_alloc</b>.</p>
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<p><b>Exception safety:</b> If an exception is thrown, the constructor has no
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effect.</p>
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<P><B>Notes:</B> <B>T</B> need not be a complete type. See the smart pointer <A href="smart_ptr.htm#Common requirements">
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common requirements</A>.</P>
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</blockquote>
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<pre>explicit shared_ptr(T * p);</pre>
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<blockquote>
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<p><b>Requirements:</b> The expression <code>delete p</code> must be well-formed
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and must not invoke undefined behavior.
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@ -136,7 +151,7 @@ template<typename Y> shared_ptr(shared_ptr<Y> const & r); // nev
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increased by one.</p>
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<p><b>Throws:</b> nothing.</p>
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</blockquote>
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<pre>shared_ptr(<A href="weak_ptr.htm" >weak_ptr</A> const & r);</pre>
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<pre>explicit shared_ptr(<A href="weak_ptr.htm" >weak_ptr</A> const & r);</pre>
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<blockquote>
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<p><b>Effects:</b> Constructs a <b>shared_ptr</b>, as if by storing a copy of the
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pointer stored in <STRONG>r</STRONG>.</p>
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@ -174,11 +189,26 @@ template<typename Y> shared_ptr & operator=(shared_ptr<Y> const
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template<typename Y> shared_ptr & operator=(std::auto_ptr<Y> & r);</pre>
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<BLOCKQUOTE>
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<P><B>Effects:</B> Equivalent to <code>shared_ptr(r).swap(*this)</code>.</P>
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<P><B>Notes:</B> The implementation is free to meet the effects (and the implied
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guarantees) via different means, without creating a temporary. In particular,
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in the example:</P>
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<pre>
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shared_ptr<int> p(new int);
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shared_ptr<void> q(p);
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p = p;
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q = p;
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</pre>
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<p>both assignments may be no-ops.</p>
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</BLOCKQUOTE>
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<h3><a name="reset">reset</a></h3>
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<pre>void reset(T * p = 0);</pre>
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<pre>void reset();</pre>
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<BLOCKQUOTE>
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<P><B>Effects:</B> Equivalent to <code>shared_ptr().swap(*this)</code>.</P>
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</BLOCKQUOTE>
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<pre>void reset(T * p);</pre>
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<BLOCKQUOTE>
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<P><B>Effects:</B> Equivalent to <code>shared_ptr(p).swap(*this)</code>.</P>
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<P><B>Notes:</B> Note the implied requirement that <b>T</b> is a complete type.</P>
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</BLOCKQUOTE>
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<pre>template<typename D> void reset(T * p, D d);</pre>
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<BLOCKQUOTE>
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@ -312,8 +342,8 @@ template<typename Y> shared_ptr & operator=(std::auto_ptr<Y> &am
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shared_ptr<T> shared_polymorphic_cast(shared_ptr<U> const & r);</pre>
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<BLOCKQUOTE>
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<p><STRONG>Requires:</STRONG> The expression <CODE><A href="../conversion/cast.htm#Polymorphic_cast">
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polymorphic_cast</A><T*>(r.get())</CODE> must be well-formed and
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its behavior defined.</p>
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polymorphic_cast</A><T*>(r.get())</CODE> must be well-formed and
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its behavior defined.</p>
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<P><B>Returns:</B> A <STRONG>shared_ptr<T></STRONG> object that stores a copy
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of <CODE><A href="../conversion/cast.htm#Polymorphic_cast">polymorphic_cast</A><T*>(r.get())</CODE>
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and shares ownership with <B>r</B>.</P>
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@ -325,8 +355,8 @@ template<typename Y> shared_ptr & operator=(std::auto_ptr<Y> &am
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shared_ptr<T> shared_polymorphic_downcast(shared_ptr<U> const & r); // never throws</pre>
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<BLOCKQUOTE>
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<p><STRONG>Requires:</STRONG> The expression <CODE><A href="../conversion/cast.htm#Polymorphic_cast">
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polymorphic_downcast</A><T*>(r.get())</CODE> must be well-formed
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and its behavior defined.</p>
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polymorphic_downcast</A><T*>(r.get())</CODE> must be well-formed
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and its behavior defined.</p>
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<P><B>Returns:</B> A <STRONG>shared_ptr<T></STRONG> object that stores a copy
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of <CODE><A href="../conversion/cast.htm#Polymorphic_cast">polymorphic_downcast</A><T*>(r.get())</CODE>
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and shares ownership with <B>r</B>.</P>
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