On 22 Oct 2005 22:02:46 +0200, Dieter Maurer <[EMAIL PROTECTED]> wrote: >"Tamas Nepusz" <[EMAIL PROTECTED]> writes on 20 Oct 2005 15:39:54 -0700: >> The library I'm working on >> is designed for performing calculations on large-scale graphs (~10000 >> nodes and edges). I want to create a Python interface for that library, >> so what I want to accomplish is that I could just type "from igraph >> import *" in a Python command line and then access all of the >> functionalities of the igraph library. Now it works, except the fact >> that if, for example, I start computing the diameter of a random graph >> of ~100000 nodes and ~200000 edges, I can't cancel it, because the >> KeyboardInterrupt is not propagated to the Python toplevel (or it isn't >> even generated until the igraph library routine returns). > >Python installs a "SIGINT" handler that just notes that >such a signal was received. The note is handled during >bytecode execution. This way, Python handles the (dangerous) >asynchronous signal synchronously (which is much safer). >But, it also means that a signal during execution of your C extension >is only handled when it finished. > >What you can do in your wrapper code: > > Temporarily install a new handler for "SIGINT" that > uses "longjmp" to quit the C extension execution when > the signal occurs. > > Note that "longjmp" is dangerous. Great care is necessary. > > It is likely that SIGINT occurrences will lead to big > resource leaks (because your C extension will have no > way to release resources when it gets quit with "longjmp"). >
Note that swapcontext() is probably preferable to longjmp() in almost all circumstances. In cases where it isn't, siglongjmp() definitely is. Jp -- http://mail.python.org/mailman/listinfo/python-list
