Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
360 views
in Technique[技术] by (71.8m points)

c++ - Passing the caller __FILE__ __LINE__ to a function without using macro

I'm used to this:

class Db {
  _Commit(char *file, int line) {
    Log("Commit called from %s:%d", file, line);
  }
};

#define Commit() _Commit(__FILE__, __LINE__)

but the big problem is that I redefine the word Commit globally, and in a 400k lines application framework it's a problem. And I don't want to use a specific word like DbCommit: I dislike redundancies like db->DbCommit(), or to pass the values manually everywhere: db->Commit(__FILE__, __LINE__) is worst.

So, any advice?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

So, you're looking to do logging (or something) with file & line info, and you would rather not use macros, right?

At the end of the day, it simply can't be done in C++. No matter what mechanism you chose -- be that inline functions, templates, default parameters, or something else -- if you don't use a macro, you'll simply end up with the filename & linenumber of the logging function, rather than the call point.

Use macros. This is one place where they are really not replaceable.

EDIT:

Even the C++ FAQ says that macros are sometimes the lesser of two evils.

EDIT2:

As Nathon says in the comments below, in cases where you do use macros, it's best to be explicit about it. Give your macros macro-y names, like COMMIT() rather than Commit(). This will make it clear to maintainers & debuggers that there's a macro call going on, and it should help in most cases to avoid collisions. Both good things.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...