On 19-Sep-07, at 7:41 AM, Michael South wrote:

I have a question about the C interface. It appears necessary to decrement the reference count of ___STILL objects before returning them:

Yes.

___SCMOBJ foo() { ___SCMOBJ result; ___EXT(___CHARSTRING_to_SCMOBJ) ("hello", &result, 0); ___release_scmobj (result); return result; }

Note that it would be much less hassle to write:

(c-declare #<<EOS char *foo() { return "hello"; } EOS )

(define foo (c-lambda () char-string "foo"))

Why is there not a race condition between decrementing the reference count (___release_scmobj) and returning the result? What if another thread wakes up the GC in the meantime?

Threading is implemented in Scheme (using continuations). Operating system threads are not currently implemented. The context switching is thus only possible outside of C functions like foo. Consequently there is no race condition.

Marc