CODEWITHSUNDEEP
c
Bleamer
Bleamer

Reputation: 647

How do I implement access specifiers in C?

I was trying to implement access specifier (not sure if that is called access specifier)

The purpose is to make a function (func2) callable only at one place(inside func1).

int func1 ()
{
   // Make func2 callable only here`
#define FUNC2_CALLABLE
   func2(); 
#undef FUNC2_CALLABLE
}

#ifdef FUNC2_CALLABLE
int func2 ()
{ 
  return 1;
}
#endif // FUNC2_CALLABLE

func2 should be callable only from func1 and not from any other place in the code.

Does the above code serve the purpose ? Any alternative suggestions

< Edit 1 >

How about doing it this way 

 int func2() 
 { 
#ifdef FUNC2_CALLABLE 
 return 1; 
#endif 
 }

Will this work ? < / Edit 1>

Upvotes: 3

Views: 1516

Answers (3)

llj098
llj098

Reputation: 1412

Maybe you can use static keyword .

But the function with static is accessible for all the code in the same file. Other files cannot access it.

Upvotes: 0

wallyk
wallyk

Reputation: 57784

There is no real way to do it. The best that can be done in standard C is to make func2 static and define it close to the bottom of the source file:

static int func2 ()
{ 
  return 1;
}

int func1 ()
{
   func2(); 
}

(end of file)

Upvotes: 0

Corbin
Corbin

Reputation: 33457

That will give you a linker error of func2 not found (func2 won't be defined if you use that).

I think you might be looking for static.

static int fake(int x) { return x * 2; }

int doSomething(int x) { int tmp = fake(x); doOtherThings(); }

The fake would not exist outside of the compilation unit (file basically).

As for allowing a function to only be called from another function, that doesn't make much sense. Just inline the code if that's your end goal.

Upvotes: 1

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