Question

I want to realize logging in my project.
I have macro, smth like

__LOG_TRACE(lg, expr,...) LOG_TRACE_STREAM(lg) << expr;

So I want to realize interface for this macro – another macro, but I want to support 2 types:

LOG_TRACE(msg);
LOG_TRACE(my_logger, msg);

I have some global logger, and first macro will write msg using global logger.
Second macro will take my_logger and write msg using it.

I can make it with LOG_TRACE(msg, my_logger); – but it’s not good, it’s harder to read in code. Order of arguments in __LOG_TRACE is not necessary.

Upd:
I don’t mean overloading macros.
Look – for example I can do this

#define LOG_TRACE(...) __LOG_TRACE(__VA_ARGS__, current_active)

Now I can write

LOG_TRACE(msg);
LOG_TRACE(msg, logger);

But I want not msg,logger and logger,msg

Answer 1

Macro overloading is not allowed in C or C++. But there are workarounds. Here’s an article that will help you “overload” your macro: http://cplusplus.co.il/2010/08/31/overloading-macros/