Thread: What does this statement mean?

File-scope means that the scope of the variable (where the variable can be used/seen) is the entire file - this means "global" variables in a file. Variables can have limited scope, e.g. be within a function or even a single block inside a function, eg.

Code:

int x;   // file scope

int func1(int y)   // function scope parameter. 
{
   int z;  // function scope local variable. 

   if (x == 1)
   {
       int w;   // Block scope
   }
   // w doesn't exist here. 
}

Edit: external means that the function/variable can be seen in another file, eg. you have "main.c" and "func.c", and declared x in main.c as above, then you can tell the compiler that there is an [code]extern int x;[/code} in func.c and it becomes the same variable as main.c. Functions don't need the extern keyword to make the function usable in another file, you just have to tell the compiler the prototype (what function name is and what the return type and parameters are) to use it.

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Mats