Hi! Currently I am puzzled by a bug, and so far my approaches to tackle it down failed. I guess I should use debugging tools such as gdb, but I did not find a tutorial or wiki page concerning "sage -gdb". For example: When I start "sage -gdb", how do I get the gdb prompt so that I can set break points?
I do not expect that you can guess the source of the problem from the following description; but at least you may understand why I am puzzled. I have an instance of some Cython extension class, relying on C data.Given certain input data, some method results in a "glibc detected: invalid next size" in openSUSE 11.0, Intel Core Duo, respectively in a SIGBUS on sage.math (and after the SIGBUS I don't get a prompt from the system, so, I have to shut down ssh), respectively SIGSEGV on sage.math when running sage -gdb. While debugging, I saved "self", in order to have a more easily reproducible example. But after loading the saved data, there is no crash. Now comes the strange thing: I found out that the error also disappears if inside the function I insert in the right place the line N = loads(dumps(self)) So, self should not be changed by this line, but the error vanishes. dumps alone does not suffice. The method in question gets a list "el" as parameter. I get an iterator from it, and give a custom name to the "next()" method: L = el.iter() Lnext = L.next It turns out: Inserting "N=loads(dumps(self))" helps if inserted after the line Lnext = L.next, but it does not help when inserted before the line. But how can this line interfere with my data? "el" is simply a list of python ints! There is no instance of my extension class in it. This is what I can't understand. Any pointer to a tutorial on relevant debugging techniques is greatly appreciated! Best regards, Simon --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
