使用__LINE__为不同的变量名称创建宏 [英] Creating macro using __LINE__ for different variable names
问题描述
Possible Duplicate:
Creating C macro with ## and LINE (token concatenation with positioning macro)
我想使用 __ LINE __
宏来生成不同的变量名。我有一个范围基准类叫Benchmark(位于utils命名空间),它的构造函数接受一个字符串。这是我创建的宏定义:
I am trying to use the __LINE__
macro to generate different variable names. I have a scoped benchmark class called Benchmark(located in the utils namespace) and it's constructor takes a string. Here is the macro definition I have created:
#define BENCHMARK_SCOPE utils::Benchmark bm##__LINE__(std::string(__FUNCTION__))
不幸的是,这会导致以下错误:
Unfortunately this causes the following error:
< some_file_name>(59):error C2374:'bm__LINE__':redefinition;多个初始化
这让我得出结论: __ LINE __
。我已根据此信息创建了我的宏。你有什么想法 __ LINE __
不会扩展吗?
This leads me to the conclusion the __LINE__
macros does not get expanded. I have created my macross according to this post. Do you have ideas why __LINE__
does not get expanded?
EDIT :可能编译器信息也是相关的。我使用visual studio 2010。
EDIT: probably the compiler info is also relevent. I am using visual studio 2010.
推荐答案
您需要使用两个宏的组合:
You need to use combination of 2 macros:
#define COMBINE1(X,Y) X##Y // helper macro
#define COMBINE(X,Y) COMBINE1(X,Y)
然后使用
COMBINE(x,__LINE__);
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