What does this mean by variable define in C [duplicate]

问题

This question already has answers here:

#define IDENTIFIER without a token (4 answers)

Using #define in C with no value (1 answer)

Closed 2 years ago.

can you guys tell me, what does this mean in C?

 #define Privileged_Data
 Privileged_Data static int dVariable

Is it specific meaningful for Compiler to address variable?

回答1:

This is just a macro Privileged_Data doing nothing. The compiler will not even see it after the preprocessor pass.

It's probably a readability or company standards decision to tag some variables like this.

回答2:

A preprocessor macro can be defined without an associated value. When that is the case, the macro is substituted with nothing after preprocessing.

So given this:

#define Privileged_Data

Then this:

Privileged_Data static int dVariable

Becomes this after preprocessing:

static int dVariable

So this particular macro has no effect on the program, and was probably put in place for documentation purposes.

来源：https://stackoverflow.com/questions/53520289/what-does-this-mean-by-variable-define-in-c