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+<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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+<title>Portability Hints: Microsoft Visual C++ 6.0 SP4</title>
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+</head>
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+<body bgcolor="#FFFFFF" text="#000000">
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+<table border="1" bgcolor="#007F7F" cellpadding="2">
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+ <tr>
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+ <td bgcolor="#FFFFFF"><img src="../c++boost.gif" alt="c++boost.gif (8819 bytes)" width="277" height="86"></td>
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+ <td><a href="../index.htm"><font face="Arial,Helvetica" color="#FFFFFF"><big>Home</big></font></a></td>
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+ <td><a href="../libs/libraries.htm"><font face="Arial,Helvetica" color="#FFFFFF"><big>Libraries</big></font></a></td>
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+ <td><a href="../people/people.htm"><font face="Arial,Helvetica" color="#FFFFFF"><big>People</big></font></a></td>
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+ <td><a href="faq.htm"><font face="Arial,Helvetica" color="#FFFFFF"><big>FAQ</big></font></a></td>
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+ <td><a href="index.htm"><font face="Arial,Helvetica" color="#FFFFFF"><big>More</big></font></a></td>
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+ </tr>
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+</table>
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+
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+<p>
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+
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+<h1>Portability Hints: Microsoft Visual C++ 6.0 SP4</h1>
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+
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+Similar to the
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+<a href="borland_cpp.html">portability hints for Borland C++</a>,
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+this page provides hints on some language features of the Microsoft Visual C++
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+version 6.0 servicepack 4 compiler.
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+
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+Each entry in the following list describes a particular issue,
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+complete with sample source code to demonstrate the effect.
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+Most sample code herein has been verified to compile with gcc 2.95.2
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+and Comeau C++ 4.2.44.
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+
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+
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+<h2>Preprocessor symbol</h2>
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+
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+The preprocessor symbol <code>_MSC_VER</code> is defined for all
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+Microsoft C++ compilers. Its value is the internal version number of the
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+compiler interpreted as a decimal number. Since a few other compilers
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+also define this symbol, boost provides the symbol
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+<code>BOOST_MSVC</code> defined in
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+<a href="../boost/config.hpp">boost/config.hpp</a>
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+to the value of _MSC_VER if and only if the compiler is really
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+Microsoft Visual C++.
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+
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+The following table lists some known values.
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+<p>
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+
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+<table border="1">
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+<tr>
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+<th>Compiler</th>
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+<th><code>BOOST_MSVC</code> value</th>
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+</tr>
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+
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+<tr>
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+<td>Microsoft Visual C++ 6.0 SP4</td>
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+<td>1200</td>
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+</tr>
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+
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+</table>
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+
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+
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+<h2>Core Language</h2>
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+
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+<h3>[chained using] Chaining <code>using</code>-declarations</h3>
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+
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+Chaining <code>using</code>-declarations do not work.
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+<pre>
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+void f();
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+
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+namespace N {
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+ using ::f;
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+}
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+
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+void g()
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+{
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+ using N::f; // C2873: 'f': the symbol cannot be used in a using-declaration
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+}
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+</pre>
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+
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+
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+<h3>[explicit-instantiation] Explicit function template
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+instantiation</h3>
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+
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+Trying to explicitly instantiate a function template leads to the
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+wrong function being called silently.
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+
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+<pre>
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+#include <stdio.h>
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+
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+template<class T>
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+void f()
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+{
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+ printf("%d\n", sizeof(T));
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+}
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+
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+int main()
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+{
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+ f<double>(); // output: "1"
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+ f<char>(); // output: "1"
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+ return 0;
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+}
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+</pre>
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+
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+
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+<h3>[for-scoping] Scopes of definitions in for-loops</h3>
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+
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+The scope of variable definitions in <code>for</code> loops should be
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+local to the loop's body, but it is instead local to the enclosing
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+block:
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+
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+
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+<pre>
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+int main()
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+{
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+ for(int i = 0; i < 5; ++i)
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+ ;
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+ for(int i = 0; i < 5; ++i) // C2374: 'i': Redefinition; multiple initialization
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+ ;
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+ return 0;
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+}
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+</pre>
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+
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+<strong>Workaround:</strong> Enclose the offending <code>for</code>
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+loops in another pair of curly braces.
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+
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+
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+<h3>[inclass-member-init] In-class member initialization</h3>
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+
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+In-class member initialization, require to implement a
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+Standard-conforming <code>std::numeric_limits</code> template, does
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+not work.
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+
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+<pre>
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+struct A
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+{
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+ static const int i = 5; // "invalid syntax for pure virtual method"
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+};
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+</pre>
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+
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+
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+<h3>[koenig-lookup] Argument-dependent lookup</h3>
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+
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+Argument-dependent lookup, also called Koenig lookup, does not work.
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+No additional namespace induced from the argument types seem to be
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+considered.
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+
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+<pre>
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+namespace N {
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+ struct A {};
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+ void f(A);
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+}
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+
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+void g()
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+{
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+ N::A a;
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+ f(a); // 'f': undeclared identifier
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+}
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+</pre>
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+
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+
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+<h3>[template-friend] Templates as friends</h3>
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+
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+A Template cannot be declared a friend of a class.
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+
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+<pre>
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+template<class T>
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+struct A {};
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+
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+struct B
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+{
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+ template<class T>
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+ friend struct A; // "syntax error"
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+};
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+</pre>
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+
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+
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+<h3>[member-template-outofline] Out-of-line definitions of member
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+templates</h3>
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+
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+Defining member templates outside their enclosing class does not work.
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+
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+<pre>
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+template<class T>
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+struct A
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+{
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+ template<class U>
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+ void f();
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+};
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+
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+template<class T>
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+template<class U> // "syntax error"
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+void A<T>::f() // "T: undeclared identifier"
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+{
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+}
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+</pre>
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+
|
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+<strong>Workaround:</strong> Define member templates in-line within
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+their enclosing class.
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+
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+
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+<h3>[partial-spec] Partial specialization</h3>
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+
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+Partial specialization of class templates does not work.
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+
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+<pre>
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+template<class T>
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+struct A {};
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+
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+template<class T>
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+struct B {};
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+
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+template<class T>
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+struct A<B<T> > {}; // template class was already defined as a non-template
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+</pre>
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+
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+<strong>Workaround:</strong> In some situations where interface
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+does not matter, member class templates can simulate partial
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+specialization.
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+
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+
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+<h3>[template-value] Dependent emplate value parameters</h3>
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+
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+Template value parameters whose type depends on a previous template
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+parameter provoke an internal compiler error if the correct syntax
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+(with "typename") is used.
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+
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+<pre>
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+template<class T, typename T::result_type> // C1001: INTERNAL COMPILER ERROR: ms
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+c1.cpp, line 1794
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+struct B {};
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+ // (omit "typename" and it compiles)
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+
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+</pre>
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+
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+
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+<h3>[wchar_t] <code>wchar_t</code> is not built-in</h3>
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+
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+The type <code>wchar_t</code> is not a built-in type.
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+
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+<pre>
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+wchar_t x; // "missing storage class or type identifier"
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+</pre>
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+
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+
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+<p>
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+<hr>
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+
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+2001-02-01 <a href="../people/jens_maurer.htm">Jens Maurer</a>
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+</body>
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+</html>
|
Jens Maurer