c++ - C++中的$符号

Question

我从开源库中读取了以下代码。令我困惑的是美元符号的用法。任何人都可以澄清代码中 $ 的含义。非常感谢您的帮助!

   __forceinline MutexActive( void ) : $lock(LOCK_IS_FREE) {}
    void lock  ( void );
    __forceinline void unlock( void ) { 
      __memory_barrier();     // compiler must not schedule loads and stores around this point
      $lock = LOCK_IS_FREE; 
    }
  protected:
    enum ${ LOCK_IS_FREE = 0, LOCK_IS_TAKEN = 1 };
    Atomic $lock;

Answer 1

有一个 gcc 开关，-fdollars-in-identifiers，它明确允许在标识符中使用 $。

也许他们启用它并使用 $ 作为与普通名称极不可能发生冲突的东西。

-fdollars-in-identifiers

Accept $ in identifiers. You can also explicitly prohibit use of $ with the option -fno-dollars-in-identifiers. (GNU C allows $ by default on most target systems, but there are a few exceptions.) Traditional C allowed the character $ to form part of identifiers. However, ISO C and C++ forbid $ in identifiers.

参见 the gcc documentation .希望链接保持良好。