使用过滤器增强日志记录

Question

我是boost-log的新手，并尝试让trivial logging with filters示例与boost-log1.1一起工作。代码如下所示：

#include <boost/log/core.hpp>
#include <boost/log/trivial.hpp>
#include <boost/log/filters.hpp>

void init()
{
    logging::core::get()->set_filter
    (
     filters::attr< logging::trivial::severity_level >("Severity") >= logging::trivial::info
     );
}

int main(int, char*[])
{
    BOOST_LOG_TRIVIAL(trace) << "A trace severity message";
}

使用clang编译此命令会导致以下错误消息：

/Users/admin/Documents/cmake tests/boost-log/main.cpp:7:5: error: use of undeclared identifier 'logging'
    logging::core::get()->set_filter
    ^
/Users/admin/Documents/cmake tests/boost-log/main.cpp:9:3: error: use of undeclared identifier 'filters'; did you mean 'boost::log_mt_posix::filters'?
         filters::attr< logging::trivial::severity_level >("Severity") >= logging::trivial::info
         ^~~~~~~
         boost::log_mt_posix::filters
/usr/local/include/boost/log/filters/has_attr.hpp:32:11: note: 'boost::log_mt_posix::filters' declared here
namespace filters {
          ^
/Users/admin/Documents/cmake tests/boost-log/main.cpp:9:18: error: use of undeclared identifier 'logging'
         filters::attr< logging::trivial::severity_level >("Severity") >= logging::trivial::info

该示例看起来是基于旧版本的boost-log，并且一些名称已更改。这个例子可以很容易的修复吗？然而，更新后的教程似乎不可用。

Answer 1

文档中的示例在includes之后似乎缺少以下行：

namespace logging = boost::log;
namespace filters = boost::log::filters;