问题
I have two versions of a c++ compiler installed on my computer. One of them recognizes the __COUNTER__ macro and the other does not. After doing some research to make the program compile in both I have yet to come across the Macro definition for __COUNTER__. Is this some special Macro done by the compiler or can I copy the definition for __COUNTER__ into my source code, if I can copy it what is the code I need.
回答1:
__COUNTER__ is a built-in in several common compilers. It is not possible to define manually. If you're stuck with a compiler that doesn't support it, your best option might be to run your code through a preprocessor that does support it before feeding it into the compiler.
回答2:
It's a special macro which has been introduced by Visual Studio and I think is now supported by GCC too.
It basically provides a unique counter over integral numbers which can be used to generate unique identifiers.
From GCC release notes:
A new predefined macro
__COUNTER__has been added. It expands to sequential integral values starting from 0. In conjunction with the##operator, this provides a convenient means to generate unique identifiers.
If you don't have it available to a compiler you can easily mimic the behavior with a static variable. But I'm not sure what you are compiling so I'm not sure how this counter is used in the code you have available.
来源：https://stackoverflow.com/questions/20768379/c-counter-definition