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// 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
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