boost - Boost::log::string_literal construction issue

Question

I'm trying unsuccessfully to use the macro BOOST_LOG_NAMED_SCOPE with no hard-coding (e.g no BOOST_LOG_NAMED_SCOPE("bla"), but BOOST_LOG_NAMED_SCOPE(some_variable); this macro uses inside a boost::log::string_literal that have no C'tor for std::string or char*. The only thing it accepts is const char[] (NOT const char*) - which doesn't help me at all because I can't hard-code it - this value must be retrieved from a function.

So, I need to find a way to construct boost::log::string_literal with std::string or char*, or somehow to edit const char[]... (I tried also to create a char[] and cast it to const char[], but failed)

Answer 1

嗯。“字符串文字”说明了一切。它只适用于文字，并且那些是根据定义（在标准中，即）char const[]。

这种设计决策（使名称在编译时已知并固定）可能有几个原因。从概念上讲，它将使日志记录“可预测”（如果范围名称不同，您将如何解释日志？），并且可能与性能有关（它甚至可以用于基于范围名称静态禁用某些日志记录，但是根据编译器的不同，输出格式等其他内容可能会提高性能）。

因此，您可以不希望对事物进行硬编码，但不希望在这样做时使用需要字符串文字的宏。

现在，您可以使用extern适当类型的变量 ( extern char const some_scope_name[])，我想这至少可以让您有机会在另一个翻译单元中定义值。