Static Variable Declaration (C)

Question

Are the following two `static` variable declarations equivalent? 1. ``` static int var1; static int var2; static int var3; ``` 2. ``` static int var1, var2, var3; ``` More specifically, in case 2, will all variables be `static`, or just `var1`?

Accepted Answer

Yes the declarations in case `1` and `2` are identical. We can see this by going to the draft C99 standard section `6.7.5` Declarators which says (emphasis mine going forward):

Each declarator declares one identifier, and asserts that when an operand of the same form as the declarator appears in an expression, it designates a function or object with the scope, storage duration, and type indicated by the declaration specifiers.

We can see the grammar from section `6.7` Declarations is as follows:

```
declaration:
   declaration-specifiers init-declarator-listopt ;
```

the declaration-specifiers include storage duration:

```
declaration-specifiers:
   storage-class-specifier declaration-specifiersopt
```

so the storage duration specifier applies to all the declarators in the init-declarator-list which has the following grammar:

```
init-declarator-list:
   init-declarator
   init-declarator-list , init-declarator
init-declarator:
   declarator
   declarator = initializer
```

You may wonder about pointers, they are handled handled differently and we can see this from the grammar in `6.7.5` for declarators:

```
declarator:
    pointeropt direct-declarator
[...]
pointer:
    * type-qualifier-listopt
    * type-qualifier-listopt pointer
```

Static Variable Declaration (C)

Solution

Problem