On Mar 29, 2010, at 10:23 AM, Jesús García Sáez wrote:

> Hi,
> 
> when is it posible to define a "string" type safely? I think, the only situation is for const char * input parameter. Because otherwise we are gonna have memory leaks.
> 
> For example, for a function like:
> 
> char *foo();
> 
> if we attach it with:
> 
> attach_function :foo, :foo, [], :string
> 
> We are gonna have a nice memory leak because nobody is gonna release that string. When we call "foo" method in ruby, we get a String object, we cannot (or I don't know how) get the actual char pointer to release it (either from ruby or with another attached function where we pass the pointer and that function calls free, delete o whatever is necessary).

You use the :strptr type for this. It returns [String, MemoryPointer], so you can do:

str, ptr = foo()
ptr.free

It's really just a simple shortcut for declaring it to be of type :pointer and asking the MemoryPointer to read itself as a String. But because this is a common pattern, we have the :strptr type.

 - Evan

> 
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