From 6ea398c446a0a4058008464b10cc9a89344f8ae9 Mon Sep 17 00:00:00 2001 From: John Maddock Date: Sat, 28 May 2005 11:51:04 +0000 Subject: [PATCH] Make it clear that POD's are not zero initialised. [SVN r29254] --- compressed_pair.htm | 115 ++++++++++++++++++-------------------------- 1 file changed, 46 insertions(+), 69 deletions(-) diff --git a/compressed_pair.htm b/compressed_pair.htm index 6aa1601..4662fc5 100644 --- a/compressed_pair.htm +++ b/compressed_pair.htm @@ -1,30 +1,19 @@ - - - - - -Header - - - - - -

Header -<boost/compressed_pair.hpp>

- -

All of the contents of <boost/compressed_pair.hpp> are -defined inside namespace boost.

- -

The class compressed pair is very similar to std::pair, but if -either of the template arguments are empty classes, then the -"empty base-class optimisation" is applied to compress -the size of the pair.

- -
template <class T1, class T2>
+   
+      Header 
+      
+      
+      
+      
+   
+   
+      
Header <boost/compressed_pair.hpp>

+      
All of the contents of <boost/compressed_pair.hpp> are defined inside 
+         namespace boost.

+      
The class compressed pair is very similar to std::pair, but if either of the 
+         template arguments are empty classes, then the "empty base-class optimisation" 
+         is applied to compress the size of the pair.

+      
template <class T1, class T2>
 class compressed_pair
 {
 public:
@@ -52,47 +41,35 @@ public:
 
 	void swap(compressed_pair& y);
 };

-
-
The two members of the pair can be accessed using the member
-functions first() and second(). Note that not all member
-functions can be instantiated for all template parameter types.
-In particular compressed_pair can be instantiated for reference
-and array types, however in these cases the range of constructors
-that can be used are limited. If types T1 and T2 are the same
-type, then there is only one version of the single-argument
-constructor, and this constructor initialises both values in the
-pair to the passed value.

-
-
Note that compressed_pair can not be instantiated if either of
-the template arguments is a union type, unless there is compiler
-support for boost::is_union, or if boost::is_union is specialised
-for the union type.

-
-
Finally, a word of caution for Visual C++ 6 users: if either
-argument is an empty type, then assigning to that member will
-produce memory corruption, unless the empty type has a "do
-nothing" assignment operator defined. This is due to a bug
-in the way VC6 generates implicit assignment operators.

-
-

-
-
Revised 08 May 2001

-
-
© Copyright boost.org 2000. Permission to copy, use, modify,
-sell and distribute this document is granted provided this
-copyright notice appears in all copies. This document is provided
-"as is" without express or implied warranty, and with
-no claim as to its suitability for any purpose.

-
-
Based on contributions by Steve Cleary, Beman Dawes, Howard
-Hinnant and John Maddock.

-
-
Maintained by John
-Maddock, the latest version of this file can be found at www.boost.org, and the boost
-discussion list at www.yahoogroups.com/list/boost.

-
-
 

-
+      
The two members of the pair can be accessed using the member functions first() 
+         and second(). Note that not all member functions can be instantiated for all 
+         template parameter types. In particular compressed_pair can be instantiated for 
+         reference and array types, however in these cases the range of constructors 
+         that can be used are limited. If types T1 and T2 are the same type, then there 
+         is only one version of the single-argument constructor, and this constructor 
+         initialises both values in the pair to the passed value.

+      
Note that if either member is a POD type, then that member is not 
+         zero-initialized by the compressed_pair default constructor: it's up to you to 
+         supply an initial value for these types if you want them to have a default 
+         value.

+      
Note that compressed_pair can not be instantiated if either of the template 
+         arguments is a union type, unless there is compiler support for 
+         boost::is_union, or if boost::is_union is specialised for the union type.

+      
Finally, a word of caution for Visual C++ 6 users: if either argument is an 
+         empty type, then assigning to that member will produce memory corruption, 
+         unless the empty type has a "do nothing" assignment operator defined. This is 
+         due to a bug in the way VC6 generates implicit assignment operators.

+      

+      
Revised 08 May 2001

+      
© Copyright boost.org 2000. Permission to copy, use, modify, sell and 
+         distribute this document is granted provided this copyright notice appears in 
+         all copies. This document is provided "as is" without express or implied 
+         warranty, and with no claim as to its suitability for any purpose.

+      
Based on contributions by Steve Cleary, Beman Dawes, Howard Hinnant and John 
+         Maddock.

+      
Maintained by John Maddock, the 
+         latest version of this file can be found at www.boost.org, 
+         and the boost discussion list at www.yahoogroups.com/list/boost.

+      
 

+