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From: Bo Persson<bop@gmb.dk>
Newsgroups: comp.std.c++
Subject: Smart pointer comparison - why a difference?
Date: Mon, 28 May 2012 14:53:04 -0700 (PDT)
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Xref: csiph.com comp.std.c++:520

In C++11, operator<  for unique_ptr [unique.ptr.special] is defined as

std::less<CT>()(x.get(), y.get())

where CT is the common_type of the unique_ptr's internal pointer typedefs.


On the other hand, operator<  for shared_ptr [util.smartptr.shared.cmp]
is defined as

std::less<V>()(a.get(), b.get())

"where V is the composite pointer type (5.9) of T* and U*."


What exactly is the difference, and why?


Bo Persson


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