diff --git a/include/boost/detail/workaround.hpp b/include/boost/detail/workaround.hpp index cad6d432..7a5aef0d 100644 --- a/include/boost/detail/workaround.hpp +++ b/include/boost/detail/workaround.hpp @@ -23,17 +23,47 @@ // When used for workarounds on the latest known version of a // compiler, the following convention should be observed: // -// #if BOOST_WORKAROUND(BOOST_MSVC, |0x1301) +// #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. It only has -// value as a comment, since the outcome of the test is always 1 -// unless BOOST_STRICT_CONFIG is defined. +// value as a comment unless BOOST_DETECT_OUTDATED_WORKAROUNDS is +// defined, in which case a compiler warning or error will be issued +// when the compiler version exceeds the argument to BOOST_CHECKED_AT # ifndef BOOST_STRICT_CONFIG -# define BOOST_WORKAROUND(symbol, test) ((symbol) != 0 && ((symbol) test)) + +# 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 => 2 if the test passes, 1 otherwise +// 1 % ((symbol test) + 1) => 1 if the test passes, 0 otherwise +// +// 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 => 1 if symbol <= x, -1 otherwise +// (symbol test) + 1 => 2 if symbol <= x, 0 otherwise +// 1 % ((symbol test) + 1) => 1 if symbol <= x, zero divide otherwise +// + +# 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) != 0 +# endif + # else + # define BOOST_WORKAROUND(symbol, test) 0 + # endif #endif // WORKAROUND_DWA2002126_HPP