Boost.Log BOOST_LOG_DOXYGEN_PASS是什么？

What's is BOOST_LOG_DOXYGEN_PASS for in Boost.Log?

本文关键字：PASS 是什么 DOXYGEN LOG Log BOOST Boost      更新时间：2023-10-16

在Boost.Log库中有一些奇怪的代码，例如在boostfilellogging .cpp中，它说

#ifndef BOOST_LOG_DOXYGEN_PASS
#define BOOST_LOG_INIT_LOG_TO_FILE_INTERNAL(z, n, data)
    template< BOOST_PP_ENUM_PARAMS(n, typename T) >
    inline shared_ptr< BOOST_LOG_FILE_SINK_FRONTEND_INTERNAL< sinks::text_file_backend > > add_file_log(BOOST_PP_ENUM_BINARY_PARAMS(n, T, const& arg))
    {
        return aux::add_file_log((
            aux::wrap_file_name(arg0, typename parameter::aux::is_named_argument< T0 >::type())
            BOOST_PP_COMMA_IF(BOOST_PP_GREATER(n, 1))
            BOOST_PP_ENUM_SHIFTED_PARAMS(n, arg)
            ));
    }
BOOST_PP_REPEAT_FROM_TO(1, BOOST_LOG_MAX_PARAMETER_ARGS, BOOST_LOG_INIT_LOG_TO_FILE_INTERNAL, ~)
#undef BOOST_LOG_INIT_LOG_TO_FILE_INTERNAL
#else // BOOST_LOG_DOXYGEN_PASS
/*!
 * The function initializes the logging library to write logs to a file stream.
 *
 * param args A number of named arguments. The following parameters are supported:
 *             li c file_name The file name or its pattern. This parameter is mandatory.
 *             li c open_mode The mask that describes the open mode for the file. See <tt>std::ios_base::openmode</tt>.
 *             li c rotation_size The size of the file at which rotation should occur. See <tt>basic_text_file_backend</tt>.
 *             li c time_based_rotation The predicate for time-based file rotations. See <tt>basic_text_file_backend</tt>.
 *             li c auto_flush A boolean flag that shows whether the sink should automatically flush the file
 *                               after each written record.
 *             li c target The target directory to store rotated files in. See <tt>sinks::file::make_collector</tt>.
 *             li c max_size The maximum total size of rotated files in the target directory. See <tt>sinks::file::make_collector</tt>.
 *             li c min_free_space Minimum free space in the target directory. See <tt>sinks::file::make_collector</tt>.
 *             li c scan_method The method of scanning the target directory for log files. See <tt>sinks::file::scan_method</tt>.
 *             li c filter Specifies a filter to install into the sink. May be a string that represents a filter,
 *                           or a filter lambda expression.
 *             li c format Specifies a formatter to install into the sink. May be a string that represents a formatter,
 *                           or a formatter lambda expression (either streaming or Boost.Format-like notation).
 * return Pointer to the constructed sink.
 */
template< typename... ArgsT >
shared_ptr< BOOST_LOG_FILE_SINK_FRONTEND_INTERNAL< sinks::text_file_backend > > add_file_log(ArgsT... const& args);
#endif // BOOST_LOG_DOXYGEN_PASS

这个宏的动机是什么?我应该启用还是禁用它?

oxygen是一个解析源代码和生成文档的程序。

这样做的目的是为了让氧看到(和记录)一些与真正的编译器看到的不同的东西。

在这种情况下，氧将看到一个可变模板，所以HTML文档会这样说:

add_file_log (ArgsT…const&args);

模板参数:
  • template<typename……ArgsT>

返回类型:

shared_ptr< BOOST_LOG_FILE_SINK_FRONTEND_INTERNAL< sinks::text_file_backend > >

函数初始化日志库，将日志写入文件流。

…等等

但是Boost Log显然在不支持可变模板的编译器上工作，所以真正的编译器看不到这个。编译器看到的是一堆非可变的模板，沿着这些行(尽管它与解释BOOST_LOG_DOXYGEN_PASS无关):

template<typename Arg1T> shared_ptr</*snip*/> add_file_log(Arg1T const& arg1);
template<typename Arg1T, typename Arg2T> shared_ptr</*snip*/> add_file_log(Arg1T const& arg1, Arg2T const& arg2);
template<typename Arg1T, typename Arg2T, typename Arg3T> shared_ptr</*snip*/> add_file_log(Arg1T const& arg1, Arg2T const& arg2, Arg3T const& arg3);
// and so on

您不希望每个条目都有单独的文档条目，这会使文档变得混乱。

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