CODEWITHSUNDEEP
cglobal-variables
physics
physics

Reputation: 161

Manipulation of global variable in C

I have a lot of global variables whose name is very long, e.g: 

var1.var2.var3.var4.myGlobalVar1[N]

And I must use this variables in my function. My question is what is the best way to manipulate this variable? is it necessary to do a copy into a local variable to increase the readability?

Upvotes: 3

Views: 161

Answers (2)

mch
mch

Reputation: 9814

if you only want to increase the readability, you can use

#define SHORTER_NAME var1.var2.var3.var4.myGlobalVar1[N]

if it is an array you can use

#define SHORTER_NAME var1.var2.var3.var4.myGlobalVar1

to access each value with SHORTER_NAME[index]

Upvotes: 4

Lundin
Lundin

Reputation: 215245

The best way to increase readability is indeed to create a local variable. This local variable will get optimized away in the final executable, so it won't affect the program's performance. The local variable can either be a hard copy of the struct member, or a pointer to it, depending on what's most convenient from case to case.

You can also use macros in various ways, but I don't recommend it, since they clutter down the global namespace.

If you still insist in using macros for whatever reason, then you should do like this:

#define SHORT var1.var2.var3.var4.myGlobalVar1
...
SHORT[i] = something;

You should not use function-like macros in this case. They aren't type safe, they are hard to read, hard to debug and hard to maintain. Macros in general are dangerous and bad practice.

Upvotes: 1

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