Poly/ML January 2009

polyml@lists.polyml.org

2 participants
3 discussions

Segmentation fault when saving state
by pclayton＠taz.qinetiq.com 03 Apr '09

03 Apr '09

David, We have noticed some interesting behaviour with the state saving in Poly/ML 5.2/5.2.1--- possibly a sign that something isn't quite as intended. If poly is started and the command PolyML.SaveState.saveState "test"; is repeatedly entered, a segmentation fault eventually occurs. On my machine it always happens after 22 times. With the debug level set to 2 or 3, we get: Bad pointer 0x0d479050 found Aborted If we enter PolyML.fullGC (); just before the 22nd go, there is no segmentation fault. However, continuing to enter the original save state command results in the exception Exception- SysErr ("Out of Memory", SOME ENOMEM) raised after 8 more goes. We found this example more by chance. We have had a few other repeatable segmentation faults when saving the state but on very large examples and these are hard to reduce down. (They may be related to the above issue.) In each case, the segmentation fault could be avoided by executing PolyML.fullGC first. Generally, if we cannot create an SML script that generates an error, what is the best way to track down an issue? Thanks, Phil The information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). The information in this communication may be confidential and/or legally privileged. Nothing in this e-mail is intended to conclude a contract on behalf of QinetiQ or make QinetiQ subject to any other legally binding commitments, unless the e-mail contains an express statement to the contrary or incorporates a formal Purchase Order. For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful. Emails and other electronic communication with QinetiQ may be monitored and recorded for business purposes including security, audit and archival purposes. Any response to this email indicates consent to this. Telephone calls to QinetiQ may be monitored or recorded for quality control, security and other business purposes. QinetiQ Limited Registered in England & Wales: Company Number:3796233 Registered office: 85 Buckingham Gate, London SW1E 6PD, United Kingdom Trading address: Cody Technology Park, Cody Building, Ively Road, Farnborough, Hampshire, GU14 0LX, United Kingdom http://www.qinetiq.com/home/notices/legal.html

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Updates in CVS
by David.Matthews＠prolingua.co.uk 29 Jan '09

29 Jan '09

There have been a couple of updates to the Poly/ML CVS repository recently apart from those already mentioned on the list. They are both in the C++ run-time system. The mechanism for waiting for external events has been improved which mainly affects Windows pipes and processes. In particular Windows.execute is now much faster when reading from a pipe. I noticed some strange warning messages when building Poly/ML on Cygwin on a new machine of the form "Warning: linker path does not have real file for library -lXXX" It turned out that this was as a result of not having installed the "file" package (/usr/bin/file) rather than anything to do with Poly/ML. Installing this fixed the problem so I've added a test in the configure script which checks for the presence of /usr/bin/file when compiling on Cygwin and produces a more explanatory message if it's not there. David

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Incorrect value for IntInf.pow (~1, ~n) for n = 1, 2, 4, 6, 8 etc.
by pclayton＠taz.qinetiq.com 17 Jan '09

17 Jan '09

In my ignorance I wrote my own exponentiation function for infinite integers, only to find IntInf.pow exists in the basis. Anyway, I ran my test cases on IntInf.pow but they didn't all pass... The following tests should be true but return false: val test = IntInf.pow; test (~1, ~1000000) = 1; test (~1, ~8) = 1; test (~1, ~6) = 1; test (~1, ~4) = 1; test (~1, ~2) = 1; test (~1, ~1) = ~1; It looks like Int.quot(j, 2) on line 117 of basis/IntInf.sml should be Int.rem(j, 2) or possibly andb(j, 1) (as in the local function power). Phil The information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). The information in this communication may be confidential and/or legally privileged. Nothing in this e-mail is intended to conclude a contract on behalf of QinetiQ or make QinetiQ subject to any other legally binding commitments, unless the e-mail contains an express statement to the contrary or incorporates a formal Purchase Order. For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful. Emails and other electronic communication with QinetiQ may be monitored and recorded for business purposes including security, audit and archival purposes. Any response to this email indicates consent to this. Telephone calls to QinetiQ may be monitored or recorded for quality control, security and other business purposes. QinetiQ Limited Registered in England & Wales: Company Number:3796233 Registered office: 85 Buckingham Gate, London SW1E 6PD, United Kingdom Trading address: Cody Technology Park, Cody Building, Ively Road, Farnborough, Hampshire, GU14 0LX, United Kingdom http://www.qinetiq.com/home/notices/legal.html

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Poly/ML January 2009