C++中运算符之间的逗号

Question

今天我遇到了这段代码(在 boost/type_index/type_index_facade.hpp中,第252-259行).

/// noexcept comparison operators for type_index_facade classes.
bool operator ==, !=, <, ... (const type_index_facade& lhs, const type_index_facade& rhs) noexcept;

/// noexcept comparison operators for type_index_facade and it's TypeInfo classes.
bool operator ==, !=, <, ... (const type_index_facade& lhs, const TypeInfo& rhs) noexcept;

/// noexcept comparison operators for type_index_facade's TypeInfo and type_index_facade classes.
bool operator ==, !=, <, ... (const TypeInfo& lhs, const type_index_facade& rhs) noexcept;

有人能解释一下这是什么意思吗？我以前从未见过像"==,!=,<,......"之类的东西.

Answer 1

你会注意到这些是写在:

#if defined(BOOST_TYPE_INDEX_DOXYGEN_INVOKED)
    ...
#endif

这只是一个让doxygen在文档中使用这些"简化"声明的黑客攻击.从未编译过这段代码.