Date: Thu, 16 May 2013 20:58:54 +0000 From: Taylor R Campbell <campb...@mumble.net>
Interrupt-safety is not quite done yet: it needs to integrate with the thread system using sqlite3_interrupt and sqlite3_progress_handler so that ^G at the REPL can usefully interrupt a long-running query, and other Scheme threads can get a chance to run during a long-running query. This will require a mechanism for calling back into Scheme and letting the Scheme stack swap around to switch threads without getting the C stack mixed up. I hoped the ffi callback mechanism might already do this, but evidently not; instead interrupts are just disabled on entry to callbacks, and the world probably comes crashing down if you try to enable them. Scheme48 has a working implementation of this. When C calls into Scheme, it passes Scheme a token and a return-to-c continuation to which Scheme must return the token. Any Scheme thread can return to the return-to-c continuation, but since the Scheme stack can swap around, the first thread to return to it might not match the token that was most recently passed to Scheme. In that case, C calls back into Scheme again saying `nope, switch threads until I get the right token'. _______________________________________________ MIT-Scheme-devel mailing list MIT-Scheme-devel@gnu.org https://lists.gnu.org/mailman/listinfo/mit-scheme-devel
