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?
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2 Answers
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.
4 Comments
Jean-François Fabre
maybe a macro to be able to insert
volatile or not.
Matthieu Brucher
Maybe in some configuration OP didn't show, perhaps.
Vect0rZ
A good example of this practice is Microsoft's SAL (Source Code Annotiation Language), where they mark the input parameters as
_In_ and the output as _Out_Jean-François Fabre
@Vect0rZ inout is cool to differentiate from out when passing a pointer to some data. for in and out you can use
const pointer or not.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.
3 Comments
GermanNerd
Q: Is this considered good practise? To me as an old-timer C guy, it seems like abuse of a language feature.
dbush
@GermanNerd I would tend to agree. There are other ways to document code.
GermanNerd
Nice to hear that. And thank you for your answer; initially this (ab)use of the #define directive had me really puzzled - like 'Is that something new in c99/c11/cxx....?'