Returning an enum from a function in C?

Question

If I have something like the following in a header file, how do I declare a function that returns an enum of type Foo?

enum Foo
{
   BAR,
   BAZ
};

Can I just do something like the following?

Foo testFunc()
{
    return Foo.BAR;
}

Or do I need to use typedefs or pointers or something?

Gat

Answer 1

In C++, you could use just Foo.

In C, you must use enum Foo until you provide a typedef for it.

And then, when you refer to BAR, you do not use Foo.BAR but just BAR. All enumeration constants share the same namespace (the “ordinary identifiers” namespace, used by functions, variables, etc).

Hence (for C):

enum Foo { BAR, BAZ };

enum Foo testFunc(void)
{
    return BAR;
}

Or, with a typedef:

typedef enum Foo { BAR, BAZ } Foo;

Foo testFunc(void)
{
    return BAR;
}

Liz

yet another reason why people dislike C++ – Dyann

Answer 2

I believe that the individual values in the enum are identifiers in their own right, just use:

enum Foo testFunc(){
  return BAR;
}

Bogey

In C, it needs enum Foo; in C++, just Foo would be OK. – Liz

Thanks. Or the type def that Kenny suggests, I suppose. – Bogey

Yes - or the typedef would work, but in C++ that is 'automatic' but in C it must be created manually. – Liz

Answer 3

I think some compilers may require

typedef enum tagFoo
{
  BAR,
  BAZ,
} Foo;

Courtly

C compilers would accept the function with the typedef in place; C++ compilers do not require it. – Liz

Answer 4

enum Foo
{
   BAR,
   BAZ
};

In C, the return type should have enum before it. And when you use the individual enum values, you don't qualify them in any way.

enum Foo testFunc()
{
    enum Foo temp = BAR;
    temp = BAZ;
    return temp;
}

Hyacinthe