Hi,

I just wan't to know the differences between 'alias' and 'typedef' as both do the same thing.

Thanks

Heinz wrote:
> Hi,
> 
> I just wan't to know the differences between 'alias' and 'typedef' as both do
> the same thing.
> 
> Thanks

Aliases provide another name for an existing type. Typedefs declare a new type which happens to be identical to an existing type. This can matter in function overloading, for instance:

alias int IntAlias;
typedef int IntTypedef;

void foo(int i) { }      // #1
void foo(IntAlias i) { } // #2 ERROR: Ambiguous with #1
void foo(IntTypedef i) { } // #3 Okay

void main() {
    int i = 1;
    IntAlias j = 2;
    IntTypedef k = 3;

    foo(i); // ERROR: Call #1 or #2?
    foo(j); // ERROR: Call #1 or #2?
    foo(k); // Okay, call #3
}

-- 
Kirk McDonald
Pyd: Wrapping Python with D
http://pyd.dsource.org

Heinz wrote:
> Hi,
> 
> I just wan't to know the differences between 'alias' and 'typedef' as both do
> the same thing.

I think the spec is pretty clear:
http://www.digitalmars.com/d/declaration.html#typedef

Have you read that yet?

--bb

Bill Baxter wrote:
> Heinz wrote:
>> Hi,
>>
>> I just wan't to know the differences between 'alias' and 'typedef' as both do
>> the same thing.
> 
> I think the spec is pretty clear:
> http://www.digitalmars.com/d/declaration.html#typedef
> 
> Have you read that yet?

And read the next few sections too.
For example, nobody has yet mentioned that alias is useful for more than just types.