Click here to Skip to main content
Click here to Skip to main content
Add your own
alternative version

Smart Pointers to boost your code

, 27 Sep 2004
A beginner's introduction to the smart pointers provided by the boost library.
Prize winner in Competition "MFC/C++ Aug 2004"
// Copyright David Abrahams 2002. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
#ifndef WORKAROUND_DWA2002126_HPP
# define WORKAROUND_DWA2002126_HPP

// Compiler/library version workaround macro
//
// Usage:
//
//     #if BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
//        ... // workaround code here
//     #endif
//
// When BOOST_STRICT_CONFIG is defined, expands to 0. Otherwise, the
// first argument must be undefined or expand to a numeric
// value. The above expands to:
//
//     (BOOST_MSVC) != 0 && (BOOST_MSVC) <= 1200
//
// When used for workarounds that apply to the latest known version 
// and all earlier versions of a compiler, the following convention 
// should be observed:
//
//     #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1301))
//
// The version number in this case corresponds to the last version in
// which the workaround was known to have been required. When
// BOOST_DETECT_OUTDATED_WORKAROUNDS is not the defined, the macro
// BOOST_TESTED_AT(x) expands to "!= 0", which effectively activates
// the workaround for any version of the compiler. When
// BOOST_DETECT_OUTDATED_WORKAROUNDS is defined, a compiler warning or
// error will be issued if the compiler version exceeds the argument
// to BOOST_TESTED_AT().  This can be used to locate workarounds which
// may be obsoleted by newer versions.

# ifndef BOOST_STRICT_CONFIG

#  define BOOST_WORKAROUND(symbol, test)                \
        ((symbol != 0) && (1 % (( (symbol test) ) + 1)))
//                              ^ ^           ^ ^
// The extra level of parenthesis nesting above, along with the
// BOOST_OPEN_PAREN indirection below, is required to satisfy the
// broken preprocessor in MWCW 8.3 and earlier.
//
// The basic mechanism works as follows:
//      (symbol test) + 1        =>   if (symbol test) then 2 else 1
//      1 % ((symbol test) + 1)  =>   if (symbol test) then 1 else 0
//
// The complication with % is for cooperation with BOOST_TESTED_AT().
// When "test" is BOOST_TESTED_AT(x) and
// BOOST_DETECT_OUTDATED_WORKAROUNDS is #defined,
//
//      symbol test              =>   if (symbol <= x) then 1 else -1
//      (symbol test) + 1        =>   if (symbol <= x) then 2 else 0
//      1 % ((symbol test) + 1)  =>   if (symbol <= x) then 1 else divide-by-zero
//

#  ifdef BOOST_DETECT_OUTDATED_WORKAROUNDS
#   define BOOST_OPEN_PAREN (
#   define BOOST_TESTED_AT(value)  > value) ?(-1): BOOST_OPEN_PAREN 1
#  else
#   define BOOST_TESTED_AT(value) != ((value)-(value))
#  endif

# else

#  define BOOST_WORKAROUND(symbol, test) 0

# endif 

#endif // WORKAROUND_DWA2002126_HPP

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

peterchen
Klippel
Germany Germany
Peter is tired of being called "Mr. Chen", even so certain individuals insist on it. No, he's not chinese.
 
Peter has seen lots of boxes you youngsters wouldn't even accept as calculators. He is proud of having visited the insides of a 16 Bit Machine.
 
In his spare time he ponders new ways of turning groceries into biohazards, or tries to coax South American officials to add some stamps to his passport.
 
Beyond these trivialities Peter works for Klippel[^], a small german company that wants to make mankind happier by selling them novel loudspeaker measurement equipment.
 

Where are you from?[^]



Please, if you are using one of my articles for anything, just leave me a comment. Seeing that this stuff is actually useful to someone is what keeps me posting and updating them.
Should you happen to not like it, tell me, too

| Advertise | Privacy | Mobile
Web01 | 2.8.140721.1 | Last Updated 27 Sep 2004
Article Copyright 2004 by peterchen
Everything else Copyright © CodeProject, 1999-2014
Terms of Service
Layout: fixed | fluid