CODEWITHSUNDEEP
cobjective-cinheritancestructstatic-variables
Alex Stone
Alex Stone

Reputation: 47354

What is the effect of having a static struct from C imported into Objective-C?

I'm debugging a legacy app and have encountered the following scenario

LegacySource.h
cFunctionModifyingSomeVariable()

LegacySource.c
static struct someVariable; //a custom struct


ObjectiveCImplementation.m
#import LegacySource.h
-(void)workWithLegacy {
   cFunctionModifyingSomeVariable(); // modifies variable declared in C class
}

What is the effect of having a static struct from C imported into Objective-C?

Do all of my Objective-C classes share the same single instance of the static struct, or does every instance get their own? In other words, if I make 3 instances of ObjectiveCImplementation, would they modify the same variable, or would their effects be independent from each other?

Upvotes: 0

Views: 75

Answers (1)

Ken Thomases
Ken Thomases

Reputation: 90621

The Objective-C code is not working with someVariable, at all. It's just calling a function. The static struct is not "imported" into Objective-C, whatever that might mean.

In any case, the variable someVariable is singular. There's just one such variable. No matter from where cFunctionModifyingSomeVariable() is called, it still just works with that one variable. That C function does not know about instances of an Objective-C class or, more generally, anything about its callers, so its behavior can't differ based on that.

Upvotes: 3

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