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How do I implement access specifiers in C?

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

The goal is to make the function (func2) callable in only 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 only be called from func1, not anywhere else in your code.

Does the above code match? Any alternative suggestions

<Edit 1>

How to do it this way

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

Will this work? </ Edit 1>

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3 answers


This will give you the linker error func2 not found (func2 will not be defined if you are using it).

I think you might be looking for statics.

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

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


The fake won't exist outside of the compilation unit (file mostly).

As far as being able to call a function only from another function, it doesn't make much sense. Just enter the code if that's your ultimate goal.

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



static int func2 ()
{ 
  return 1;
}

int func1 ()
{
   func2(); 
}

(end of file)
0


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Perhaps you can use a keyword static

.

But function c static

is available for all code in the same file. Other files cannot access it.

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