Re: [Chicken-users] FFI and allocation/garbage collection

[John Cowan]

Alex scripsit:

> I was wondering how the FFI wraps C functions which return strings. When
> the C strings are converted into Scheme strings, is the data copied (so
> that the Scheme string is an ordinary GC-able Scheme object), or does
> the Scheme string share the C string's data, so that automatic GC is not
> possible?

There are three cases, depending on what type a foreign-lambda or
foreign-lambda* returns:

        c-string: The string contents are copied by Chicken.

        c-string*: The string contents are copied by Chicken
                and then freed (this is useful when the C side
                mallocs a string).

        c-pointer: Chicken gets a pointer object rather than
                a string object (the lolevel unit has tools
                for manipulating these) and the C side is
                responsible for keeping the string allocated.

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